A review of recent clinical trials of the nutritional supplement Chlorella pyrenoidosa in the treatment of fibromyalgia, hypertension, and ulcerative colitis

CONTEXT

It has been suggested that the consumption of natural "whole foods" rich in macronutrients has many healthful benefits for those who otherwise ingest a normal, nonvegetarian diet. One example is dietary supplements derived from Chlorella pyrenoidosa, a unicellular fresh water green alga rich in proteins, vitamins, and minerals.

OBJECTIVE

To find evidence of the potential of chlorella dietary supplements to relieve signs and symptoms, improve quality of life, and normalize body functions in people with chronic illnesses, specifically fibromyalgia, hypertension, and ulcerative colitis.

DESIGN

Double-blind, placebo-controlled, randomized clinical trials.

SETTING

Virginia Commonwealth University's Medical College of Virginia.

PATIENTS

Fifty-five subjects with fibromyalgia, 33 with hypertension, and 9 with ulcerative colitis.

INTERVENTION

Subjects consumed 10 g of pure chlorella in tablet form and 100 mL of a liquid containing an extract of chlorella each day for 2 or 3 months.

MAIN OUTCOME MEASURES

For fibromyalgia patients, assessments of pain and overall quality of life. For hypertensive patients, measurements of sitting diastolic blood pressure and serum lipid levels. For patients with ulcerative colitis, determination of state of disease using the Disease Activity Index.

RESULTS

Daily dietary supplementation with chlorella may reduce high blood pressure, lower serum cholesterol levels, accelerate wound healing, and enhance immune functions.

CONCLUSIONS

The potential of chlorella to relieve symptoms, improve quality of life, and normalize body functions in patients with fibromyalgia, hypertension, or ulcerative colitis suggests that larger, more comprehensive clinical trials of chlorella are warranted.

IL-6 secretion by a rat T9 glioma clone induces a neutrophil-dependent antitumor response with resultant cellular, antiglioma immunity

Previously, we reported that IL-6 transduction attenuates tumor formation of a rat T9 glioma clone (termed T9.F). This study focuses on the mechanisms of the antitumor response elicited by IL-6 and the generation of glioma immunity. Ten days post s.c. inoculation of T9. F- or IL-6-secreting T9.F cells (T9.F/IL6/hi), tumor nodules were removed and their leukocytic infiltrate was analyzed by FACS with Ab markers for T cells, B cells, granulocytes, and monocytes. T9. F/IL6/hi tumors showed a marked increase in granulocytes as compared with parental T9.F tumors, and histological examination revealed that the granulocytes were neutrophils. Animals made neutropenic failed to reject T9.F/IL6/hi tumors. FACS analysis of 17-day T9. F/IL6/hi regressing tumors and T9.F progressing tumors did not reveal any significant differences in the leukocytic infiltrates. Tumor-specific effector cells were detected in the spleens harvested from animals bearing 17-day, regressing, T9.F/IL6/hi tumors. In vitro, these effector cells lysed T9.F cells, proliferated in response to T9.F stimulator cells, and produced Th1 cytokines (IL-2 and IFN-gamma) but not the Th2 cytokine, IL-4, when cocultured with T9.F stimulator cells. Rats that had rejected s.c. T9.F/IL6/hi tumors displayed a delayed-type hypersensitivity response when injected with viable T9.F cells in the contralateral flank. Passive transfer of spleen cells from these animals transferred glioma immunity to naive recipients and depletion of CD3(+) T cells, before transfer, completely abolished immunity, whereas depletion of CD8(+) T cells had moderate inhibitory effects on the transfer of immunity.

Interleukin-6 transduction of a rat T9 glioma clone results in attenuated tumorigenicity and induces glioma immunity in Fischer F344 rats

We transduced a highly tumorigenic T9 clone (T9.F), isolated from the rat T9 glioblastoma cell line, with a retroviral expression vector containing the human IL-6 cDNA and investigated the effects of IL-6 secretion on glioma formation in the syngeneic Fischer rat. Two subclones producing high and low levels (35 and 3.5 ng/10(6) cells/48 h) of IL-6 were identified and were termed T9.F/IL6/hi and T9.F/IL6/lo, respectively. Subcutaneous (SC) injection of 1 x 10(6) parental T9.F cells resulted in 100% tumor formation and progression. When 1 x 10(6) IL-6 secreting T9.F cells were injected SC, a small palpable tumor formed which sometimes regressed. In this regard, no tumors were detected after 30 days in 76% (13/17) of animals injected with T9.F/IL6/hi cells, whereas only 10% (1/10) of the rats injected with T9.F/IL6/lo cells completely rejected their tumors within this time frame. The addition of an IL-6 neutralizing antibody to the T9.F/IL6/hi SC inoculum followed by an intratumoral injection of the IL-6 neutralizing antibody, seven days later, abrogated the anti-tumor effects. Animals that rejected the IL-6 secreting tumors were 100% protected from subsequent intracranial (IC) challenges with the parental T9.F glioma as well as the original T9 glioblastoma; partially protected from an IC challenge with the unrelated, syngeneic RT-2 glioma; but were not protected from an IC challenge with the syngeneic MadB106 adenocarcinoma. When 1 x 10(4) cells were injected in the brain of naive animals, survival time was significantly increased for those rats implanted with T9.F/IL6/hi cells, but not T9.F/IL6/lo cells, as compared to animals implanted with T9.F parental cells (p = 0.003). This study demonstrates that IL-6 secretion attenuates SC and IC glioma growth and SC rejection of IL-6 secreting T9.F cells induces long-term glioma immunity which is effective in the brain.

Nutritional supplementation with Chlorella pyrenoidosa for patients with fibromyalgia syndrome: a pilot study

Fibromyalgia syndrome is a common, chronic musculoskeletal disorder of unknown aetiology. While available therapy is often disappointing, most patients can be helped with a combination of medication, exercise and maintenance of a regular sleep schedule. The objective of the present study was to determine if adding nutritional supplements derived from the unicellular green alga, Chlorella pyrenoidosa, produced any improvements in the clinical and functional status in patients with moderately severe symptoms of fibromyalgia syndrome. Eligible patients had 2+ palpable tenderness at 11 or more of 18 defined tender points and had a tender point index (TPI) of at least 22. Each day for 2 months, participants consumed two commercially available Chlorella-based products, 10 g of 'Sun Chlorella' tablets and 100 mL of liquid 'Wakasa Gold'. Any amelioration of symptoms was validated and quantified using semi-objective and subjective outcome measures systematically administered at clinic visits on days 0, 30 and 60 of the diet therapy. Eighteen of the 20 patients enrolled completed the 2 month trial. The average TPI for the group which at onset was 32, decreased to a mean of 25 after 2 months. This decrease was statistically significant (p = 0.01), representing a 22% decrease in pain intensity. Blood samples taken on each occasion indicated no significant alterations in serum chemistries, formed elements, and circulating lymphocyte subsets. Compilations of the results of patient interviews and self-assessment questionnaires revealed that seven patients felt that the dietary supplement had improved their fibromyalgia symptoms, while six thought they had experienced no change, and five believed the symptoms had worsened over the time of the trial. The results of this pilot study suggest that dietary Chlorella supplementation may help relieve the symptoms of fibromyalgia in some patients and that a larger, more comprehensive double-blind, placebo-controlled clinical trial in these patients is warranted.

A double-blind, placebo-controlled study of the safety, tolerability and pharmacokinetics of CP-101,606 in patients with a mild or moderate traumatic brain injury

CP-101,606 is a postsynaptic antagonist of the glutamate-mediated NR2B subunit of the N-methyl-D-aspartate (NMDA) receptor. When administered intravenously (i.v.) at the time of injury, CP-101,606 is neuroprotective in animal models of traumatic brain injury (TBI) and ischemia. Minimal adverse effects have been observed in normal human volunteers given i.v. doses of up to 3 mg/kg/hr for 72 hours. The objective of the present clinical trial was to assess the safety, pharmacokinetics, and tolerability of CP-101,606 infused for various times in patients who had suffered either an acute moderate or mild TBI (Glasgow Coma Score 9-14) or hemorrhagic stroke. Patients began receiving treatment within 12 hours of brain injury. A total of 53 subjects (45 with TBI and 8 with stroke) were randomized in a double-blind fashion to receive CP-101,606 or placebo (4 drug: 1 placebo). Drug/placebo was administered by i.v. infusion (0.75 mg/kg/hr) for 2 hours and then stopped (n = 25) or continued for 22 hours (n = 4) or 70 hours (n = 24) at a rate of 0.37 mg/kg/hr. Mean plasma drug concentrations were well above the predicted therapeutic concentration of 200 ng/ml within two hours of initiating treatment and were sustained as long as drug was infused. All the patients tolerated their drug/placebo treatment, and there were no clinically significant cardiovascular or hematological abnormalities in either group. A Neurobehavioral Rating Scale, used to detect personality changes and behavioral disturbances, indicated that all subjects showed an improvement from their postinjury, predosing baseline but did not significantly differ from each other with respect to type of head injury and/or treatment with drug or placebo. Modified Kurtzke Scoring also showed a similar pattern of improvement irrespective of type of head injury or drug/placebo treatment. This study suggests that CP-101,606, infused for up to 72 hours has no psychotropic effects and is well-tolerated in patients who have sustained a mild or moderate TBI or hemorrhagic stroke.

An open-label study of CP-101,606 in subjects with a severe traumatic head injury or spontaneous intracerebral hemorrhage

CP-101,606 is a postsynaptic antagonist of N-methyl-D-aspartate (NMDA) receptors bearing the NR2B subunit. When administered intravenously (i.v.), it decreases the effects of traumatic brain injury (TBI) and focal ischemia in animal models. Therapeutic plasma concentrations (200 ng/ml) in animals, have been well tolerated in healthy human volunteers. The purpose of the present dose escalation study was to assess the safety, tolerability, and pharmacokinetics of CP-101,606 in subjects who had suffered either an acute severe TBI (Glasgow Coma Scale 3-8) or spontaneous intracerebral hemorrhage. Thirty patients, 20 with a TBI and 10 with a stroke, were enrolled in the trial and began receiving an i.v. infusion of CP-101,606 for 2 hours, 24 hours, or 72 hours within 12 hours of brain injury. For the first two hours, the drug was given a rate of 0.75 mg/kg/hr and then stopped (n = 17) or continued for 22 (n = 2) or 70 hours (n = 11) at 0.37 mg/kg/hr. Plasma and cerebrospinal fluid (CSF) were collected at serial times during and after treatment. There were no consistent changes in blood pressure or pulse nor any clinically significant hematological or electrocardiogram (ECG) abnormalities attributable to CP-101,606. No adverse events or behavioral changes were considered to be related to the drug. Plasma concentrations of CP-101,606 over 200 ng/ml were rapidly achieved in the blood and CSF within two hours and were sustained there as long as the drug was infused. CSF concentrations were slightly higher than that in plasma by the end of infusion suggesting good penetration of CP-101,606 into the CSF. Outcome in the severe TBI patients, as measured by the Glasgow Outcome Score at six months, suggested that a two-hour infusion yielded a range of scores similar to contemporary patients with a severe TBI treated at our hospital while the outcomes of the patients treated with either a 24- or 72-hour infusion were better on average. Thus, these results indicate that CP-101,606 infused for up to 72 hours is well tolerated, penetrates the CSF and brain, and may improve outcome in the brain-injured patient.

Molecular detection of tumor-associated antigens shared by human cutaneous melanomas and gliomas

Both melanocytes and glial cells are derived embryologically from the neural ectoderm. Their malignant transformed counterparts, melanoma and glioma cells, respectively, may share common antigens. Numerous tumor-associated antigens have been identified in melanomas but only a few a gliomas. Using an established reverse transcriptase polymerase chain reaction plus Southern blot assay, we compared the mRNA expression of melanoma-associated antigens (MAAs) of melanomas to brain tumors primarily derived from glial cells. The MAAs studied included tyrosinase (Tyr), tyrosinase-related protein-1 and -2 (TRP-1 and TRP-2), gp100, human melanoma antigen-encoding genes 1 and 3 (MAGE-1 and MAGE-3), and melanotransferrin (p97). Glioblastoma multiforme (n = 21), anaplastic astrocytoma (n = 3), ependymoma (n = 2), meningioma (n = 3), oligodendroglioma (n = 1), and melanoma (n = 12) tumor specimens were assayed for MAA mRNA expression. Glioblastoma multiforme, astrocytoma, and melanoma cell lines were also assayed. We observed that individual MAA mRNAs were expressed in these brain tumors and cell lines at varying frequencies. The melanogenesis-pathway-related MAAs Tyr, TRP-1, TRP-2, and gp100 mRNAs were also expressed at different levels in normal brain tissues but at a much lower frequency than in glioblastoma multiforme and melanoma. MAGE-1 and MAGE-3 mRNA were expressed in different types of tumor specimens and cell lines but never in normal brain tissue. Tumor antigen p97 was expressed in all types of tumors and also in normal brain tissues. These studies demonstrate that melanomas and primary brain tumors express common MAAs and could be exploited in patients with malignant glioma by active specific immunotherapy against these common MAAs.

Adoptive immunotherapy of malignant glioma using tumor-sensitized T lymphocytes

Malignant glioma remains one disease for which there is no curative therapy. Clearly there is a need to explore new and innovative approaches for their treatment. In this report, we review our preclinical trial of a new adoptive immunotherapy protocol using cytotoxic T lymphocytes (CTL) which had been sensitized to glioma in vivo and then activated and their number expanded ex vivo using compounds which enhance signal transduction. These glioma-sensitized lymphocytes, when introduced systemically into rats with either an intracerebral or intradermal glioma, eradicated or slowed the progression of their tumor. These results indicate for the first time that a reproducible and sustained eradication of a malignant glioma could be achieved by the adoptive transfer of tumor-sensitized, ex vivo expanded CTL. A Phase I clinical trial is now underway to test the safety and potential efficacy of this immunotherapy in patients with recurrent malignant glioma.

Ex vivo expansion of tumor-draining lymph node cells using compounds which activate intracellular signal transduction. I. Characterization and in vivo anti-tumor activity of glioma-sensitized lymphocytes

It has been shown that adoptive immunotherapy can be curative for established malignant tumors. The key to this treatment lies in obtaining sufficient numbers of lymphocytes which are sensitized to recognize tumor antigens and carry out immunological reactions to destroy tumor cells. Reported here are the results of experiments to: 1) sensitize lymphocytes to the antigens of rat glioma cells and expand them ex vivo for use in adoptive immunotherapy, 2) characterize the cells of the expanded population, and 3) evaluate antitumor activity in a cohort of rats with well-established intracranial gliomas. Viable RT-2 glioma cells were injected into the hind foot pads of syngeneic Fischer 344 rats. After 10 days, the tumor draining lymph nodes (DLN) were harvested from the injected limbs and mechanically dissociated. The cells of the DLN were then suspended in culture medium supplemented with low dose interleukin-2 (IL-2) and incubated for 18 hours with Bryostatin-1 and ionomycin (Bryo/Io) to stimulate expansion. The cells were next washed to remove the Bryo/Io and resuspended in culture medium and IL-2. Population expansions of 40- to 100-fold were seen after 8 days. Flow cytometric analysis showed these cells to be a nearly pure population of T lymphocytes of the CD3+CD8+ phenotype. Intravenous injection of the ex vivo expanded DLN cells did not significantly improve survival of rats with a seven-day intracerebral RT-2 glioma, although, compared to untreated controls, the tumors of the treated animals were smaller, showed no necrosis, and appeared to be less infiltrative. Furthermore, the treated animals had a pronounced lymphocytic infiltration of their tumors with greater associated degrees of hemorrhagic change and peritumoral edema. When the ex vivo expanded DLN cells were intravenously injected into three-day intracerebral RT-2 glioma models, tumors were almost always eliminated and the animals survived their tumor challenge. We conclude that successful expansion of glioma-sensitized DLN lymphocytes is possible and that adoptive immunotherapy using these cells is capable of effectively limiting the progression of large gliomas, while totally eradicating small ones.

Ex vivo expansion of tumor-draining lymph node cells using compounds which activate intracellular signal transduction. II. Cytokine production and in vivo efficacy of glioma-sensitized lymphocytes

We have investigated the anti-tumor activity of ex vivo activated and expanded T cells which had been sensitized in vivo to one of two different syngeneic rat glioma cell lines; D74 or RT-2. Rats were sensitized by inoculation of irradiated tumor cells into each hind foot pad. After 10 days, the tumor-draining lymph node (DLN) from each popliteal region was excised and prepared as a single cell suspension. Tumor-DLN lymphocytes were next activated overnight in RPMI-1640 medium containing 10% fetal bovine serum (FBS), Bryostatin-1 (5 nM), ionomycin (1 microM), and 20 U human recombinant interleukin-2 (IL-2) per ml. Culture for seven days in RPMI-1640 supplemented with FBS and IL-2 resulted in approximately 100-fold expansion of the lymphocyte population. Both D74- and RT-2-sensitized T cells constitutively secreted tumor necrosis factor-alpha, and both lymphocyte populations produced comparable amounts of the cytokine when co-cultured with either glioma cell line. Neither D74- and RT-2-sensitized effectors constitutively secreted gamma-interferon (gamma-IFN), but both populations produced gamma-IFN when exposed to either glioma cell line in vitro. D74-sensitized T cells released significantly more gamma-IFN than the RT-2 DLN lymphocytes. In vitro Chromium-release assays indicated that RT-2-sensitized T cells were more cytotoxic for RT-2 targets than for the D74 line and that D74-sensitized effectors were also more cytotoxic for RT-2 targets. To assess in vivo therapeutic efficacy, rats who had been inoculated intradermally with RT-2 cells three days earlier received an intravenous injection of RT-2- or D74-sensitized DLN cells (10(6) cells/gram body weight) expanded after activation with Bryostatin-1 and ionomycin or an equal number of lymphokine-activated killer (LAK) cells. Tumor diameters were measured daily and revealed that injection of glioma-sensitized lymphocytes led to the elimination of tumor while treatment with LAK cells had no therapeutic benefit. These results indicate, that at least for these two glioma lines, gamma-IFN release, rather than in vitro cytotoxicity, was a better predictor for in vivo immunotherapeutic efficacy of the glioma-sensitized, expanded T cells.

Effects of an intratumoral injection of human recombinant tumor necrosis factor-alpha on cerebrovascular permeability and leukocytic infiltration in a rat glioma model

The pro-inflammatory and blood-brain barrier (BBB) effects of intratumoral (IT) injection of human recombinant tumor necrosis factor-alpha (rTNF-alpha) were studied in the Fischer rat RT-2 glioma model. Animals received a single stereotaxic injection of either 6 x 10(4) U rTNF-alpha or excipient (vehicle) into the center of an intracerebrally implanted glioma. In order to demonstrate any effects rTNF-alpha might have on the BBB, studies were conducted using endogenous IgG (150 kD) as a tracer. Forty-eight hours following injection of excipient, a margin of peritumoral IgG extravasation was observed while rats treated with 6 x 10(4) U rTNF-alpha showed a dense and extensive IgG extravasation involving both hemispheres. Histological examination revealed that an IT rTNF-alpha injection induced leukocytic adherence, neutrophilic cuffing and infiltration throughout the lesion from 12 to 72 h after injection. These histological observations were supported by quantification of cerebral myeloperoxidase (MPO) levels which indicated a significant increase in neutrophils over the excipient recipients at 4 and 12 h. These MPO levels contrasted with our earlier studies in normal rats which revealed no significant difference in tissue MPO levels following injection of excipient or rTNF-alpha. In addition, when MPO levels in tumor models and normal rats receiving TNF were compared, a significantly greater presence of neutrophils was seen in tumor models at 12 h post-TNF injection. We believe that the increased inflammatory response seen in a progressing glioma compared to normal brain may be the result of decreased resistance to leukocytic infiltration due to increased vascular surface area, the lack of infiltration-resistant perivascular basement membrane, and/or increased extracellular space.

The effects of acute exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin on glioma-specific cytotoxic T-cell activity in Fischer 344 rats

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is one of the most potent environmental immunomodulating agents identified so far. Historically, mice have been used to model mammalian immunobiology and most of the data gathered on the immunotoxicity of TCDD has been obtained from studies with mice. However, rats have been used more extensively in toxicological research to establish human risk assessment criteria. A need exists, therefore, to develop a database using the rat model in immunotoxicology so that complete animal toxicity studies can be conducted. We have treated female Fischer 344 rats with a single i.p. dose of 0.3, 3.0, or 30.0 micrograms/kg TCDD or corn oil vehicle and examined cytotoxic T-cell (CTL) activities 24 days following treatment. Syngeneic in vivo tumor-specific CTLs were generated that model cell-mediated immune reactions against neoplastically transformed self antigens. RT2, a virally-induced Fischer 344 rat glioma, and D74, a ethylnitrosurea-induced Fischer 344 rat glioma were used as targets. This immunological parameter was compared to body, thymic, and liver weights as well as liver ethoxyresorufin deethylase (EROD) activity on day 24 post-TCDD treatment. The results indicate that Fischer 344 rats are very sensitive to TCDD as indicated by severe thymic atrophy and EROD induction at all three doses. In contrast, CTL activity was only marginally affected by these same doses of TCDD with only a modest suppression noted at the highest dose. These results indicate that the CTL response in rats may not be useful in characterizing the effects of this xenobiotic on immunocompetence in the rat.

Blood-brain barrier changes following intracerebral injection of human recombinant tumor necrosis factor-alpha in the rat

Human recombinant tumor necrosis factor-alpha (rTNF-alpha) was administered to normal Fischer 344 rats by stereotaxic intracerebral (IC) injection. Animals receiving a single injection of either 6 x 10(4) U rTNF-alpha or an equivalent volume of excipient (vehicle) in their right parietal lobe. In order to demonstrate any effects rTNF-alpha might have on the blood-brain barrier (BBB), two studies were conducted, one employing exogenous horseradish peroxidase (HRP,44 kD) as a tracer of BBB permeability and the other using endogenous IgG (150 kD). Rats given rTNF-alpha showed transitory BBB permeability to HRP by 24 hours post-injection; this BBB compromise was determined to be no longer than 60 hours. In the other study, IgG was seen to cross the BBB by 48 hours post-rTNF-alpha injection. Alternatively, rats injected IC with excipient showed only limited BBB opening as a result of injection-induced trauma. We conclude that human rTNF-alpha, injected IC into normal rats triggers a temporary breakdown in BBB integrity which begins sometimes between 12 and 24 hours post-injection, is large enough to permit macromolecules of at least 150 kD to pass, and resolves by 72 hours post-injection.

Primary brain tumors differ in their expression of octamer deoxyribonucleic acid-binding transcription factors from long-term cultured glioma cell lines

Nervous system-specific transcription factors that bind to the octameric deoxyribonucleic acid sequence motif ATGCAAAT (or ATTTGCAT) are known as N-Oct proteins. Neurons and glia contain the ubiquitous Oct-1 protein and four polypeptide complexes termed N-Oct-2, N-Oct-3, N-Oct-4, and N-Oct-5. Previously, we showed that N-Oct proteins are differentially expressed by human neuroblastoma and glioblastoma cell lines in vitro. We have now extended this work to freshly isolated human primary and metastatic brain tumors. Contrary to brain tumor cell lines, of the five astrocytomas and three glioblastomas analyzed, all but two tumors displayed the complete N-Oct protein profile, irrespective of histopathological tumor grade. Two astrocytomas were negative for N-Oct-4. Ten of 13 ependymomas exhibited N-Oct-2, N-Oct-3, and N-Oct-4 but lacked the N-Oct-5 complex. In contrast, brain metastases of two patients with extracerebral carcinomas contained only Oct-1, and cerebral metastases from two cases of B cell lymphomas showed Oct-1 and Oct-2 complexes, the characteristic Oct protein pattern of B lymphocytes. Thus, metastatic carcinoma and lymphoma expressed a non-nervous system phenotype of Oct proteins.

Histopathological effects of intracerebral injections of human recombinant tumor necrosis factor-alpha in the rat

Human recombinant tumor necrosis factor-alpha (rTNF-alpha) was administered to normal Fischer 344 rats by stereotaxic intracerebral (IC) injection. Animals received a single injection of either 6 x 10(4) U rTNF-alpha or excipient in their right parietal lobe. Others received three consecutive daily injections of either 6 x 10(4) U rTNF-alpha or excipient to examine effects of higher accumulative doses. Histological examination of the brain revealed that both single and multiple IC injections of rTNF-alpha triggered an immigration of circulating leukocytes into the site of TNF-alpha injection. After one injection, this cell population was composed mainly of macrophages and neutrophils. Maximal leukocytic influx occurred by 48 h and was composed mostly of neutrophils which were limited to the injection site and perivascular space. Quantitation of the inflammatory reaction by measurement of tissue myeloperoxidase levels supported these histological observations. One day after multiple rTNF-alpha injections, leukocytic adhesion to endothelium, vascular cuffing and leukocytic infiltration into the neuropil was observed at levels comparable to those seen 3 days following a single rTNF-alpha injection. We conclude that while one or more IC injection(s) of 6 x 10(4) U rTNF-alpha was well tolerated in normal rats, at this dose the cytokine triggers a pronounced leukocytic infiltration at the site of injection. These results support a role for TNF-alpha as a mediator in inflammatory responses within the central nervous system.

Cerebrovascular effects and tumor kinetics after a single intratumoral injection of human recombinant interleukin-2 alone or in combination with intravenous chemotherapy in a rat model of glioma

It is well documented that drug delivery into experimental and human brain tumors is limited by the variably intact blood-brain barrier (BBB) at the growing edge. The aim of the present investigation was to examine the histopathological changes that occur after a single intralesional injection of human recombinant interleukin-2 (rIL-2) into a growing glioma and determine whether the injection improved delivery of cytotoxic drug into the neuropil surrounding the site of lymphokine injection. Because an intracerebral injection of rIL-2 causes a temporary breakdown in the BBB, we hoped to enhance drug penetration into peritumoral areas of brain with an intact BBB by using the novel biomodulating effect of rIL-2 on the cerebral endothelial cells. The results demonstrated that an intralesional injection of 7.2 x 10(4) National Units rIL-2 on Day 7 after tumor inoculation did not accentuate the already increased cerebrovascular permeability produced by the glioma nor did rIL-2 trigger additional or aggravate neurological deficits in glioma-bearing rats. Before the administration of chemotherapy in vivo, the RT-2 glioma cells were tested for in vitro sensitivity by colorimetric assay. At 24 hours after exposure to either methotrexate (MTX), vincristine (VIN), or doxorubicin (DOX), no significant inhibition of metabolic activity was observed. In contrast, a timed pulsed of any drug for 5 minutes caused significant dose-dependent inhibition of RT-2 glioma cells at 48 hours to 5 days after drug administration. Animal models receiving an intralesional injection of rIL-2 followed 3 days later by an intravenous dose of 30 mg/kg MTX, 0.23 mg/kg VIN, or 10 mg/kg DOX demonstrated that only MTX combined with intralesional rIL-2 significantly inhibited intracranial proliferation of RT-2 glioma cells. Use of intralesional rIL-2 and intravenous chemotherapy, however, did not significantly increase survival in this animal model of glioma. These results show that the combination of cytotoxic drugs with intralesional rIL-2 can be safely applied in the management of glioma and may form a rational basis for additional pharmacological investigations of a wider assortment of chemotherapies in combination with rIL-2 for intracranial malignancies.

Systemic treatment with murine recombinant interleukin-1 beta inhibits the growth and progression of malignant glioma in the rat

We investigated the effects of daily subcutaneous (SC) injections of 100, 200, or 400 micrograms/kg murine recombinant interleukin-1 beta (rIL-1 beta) or its excipient on normal Fischer 344 rats and ones harboring a malignant RT-2 glioma. The tumor model has a predictable course with animals dying on days 14-17 following an intracerebral inoculation of 10(4) RT-2 glioma cells. Treatments with rIL-1 beta or excipient began on day seven post-tumor inoculation and continued for 7 days. We observed no significant effect on core body temperatures although there was a significant (p less than 0.05) decrease in body weight in all rIL-1 beta treated animals. When tumor-bearing animals became moribund, they received an intraperitoneal injection of bromodeoxyuridine (BUdr) and were sacrificed two hours later. Blood samples were obtained prior to their sacrifice by transcardiac perfusion with a buffered aldehyde solution. Recombinant IL-1 beta affected blood differentials; causing neutrophilia, lymphopenia, and slight thrombocythemia. The BUdr labeling index of glioma cells did not significantly differ between treatment groups, although tumors differed histologically at the time of necropsy. Tumors of rIL-1 beta treated animals had more extensive necrosis and a greater degree of leukocyte infiltration. Survival studies were conducted in which rats were given continuous daily SC injections of rIL-1 beta until day of death. Overall survival between the two groups differed significantly in studies using 100 micrograms/kg/d (p less than 0.05); rIL-1 beta treated rats had a mean survival time of 22 (+/- 3.0) days while excipient controls had a mean survival time of 17 (+/- 0.5) days. Similarly, at a dose of 200 micrograms rIL-1 beta/kg/d, mean survival was significantly (p less than 0.05) increased as compared to excipient controls (18.75 +/- 1.5 vs. 15.25 +/- 1.7 days, respectively). Daily injections of 400 micrograms/kg did not significantly increase the survival of glioma bearing animals, possibly as a consequence of rIL-1 beta toxicity at this dose.

Corticosteroids inhibit the delivery of short-term activational pulses of phorbol ester and calcium ionophore to human peripheral T cells

Although there is evidence that corticosteroids inhibit receptor-ligand-induced phospholipid hydrolysis, the immunosuppressive effects of these agents downstream of protein kinase C (PK-C) activation and cytosolic Ca2+ mobilization is unclear. Previous studies indicated that T cell proliferative activation could be achieved with simultaneous short-term (e.g., 15-120 min) exposure to agents activating PK-C and elevating cytosolic Ca2+. In the studies reported here, similar procedures were utilized for determining whether corticosteroids alter T cell activation signals downstream of second messenger events. Dexamethasone interfered with T cell activation induced by short-term exposure to phorbol 12,13-dibutyrate (PDBu) and the calcium ionophore, ionomycin. The inhibitory effect was evident with as little as 15 min of exposure to dexamethasone and T cell activating agents, making mechanisms involving de novo protein synthesis unlikely. Dexamethasone's effects in this system were blocked by the steroid receptor antagonist RU-486, indicating that the inhibition was mediated through the glucocorticoid receptor. The inclusion of recombinant interleukin-2 (IL-2) only partially overcame the dexamethasone inhibitory effect. Long-term (i.e., 48 hr) direct stimulation of PK-C with either PDBu or the non-tumor-promoting PK-C activator, bryostatin 1, also substantially overcame dexamethasone's effects, resulting in a recovery of IL-2 production and significant restoration of the T-cell proliferative response. These observations suggest that treatment with a PK-C-activating agent such as bryostatin 1 could reduce glucocorticosteroid-induced immunosuppression.

In vitro analysis of the proliferative potential of T cells from patients with brain tumor: glioma-associated immunosuppression unrelated to intrinsic cellular defect

Patients harboring a malignant brain tumor have been described as being highly immunosuppressed, as evidenced by reduced numbers of T cells and the decreased ability of their lymphocytes to produce interleukin-2 (IL-2). In order to determine whether an intrinsic abnormality exists in the T lymphocytes of glioma patients and to evaluate what role corticosteroids may play in glioma-associated immunosuppression, in vitro T cell proliferative function in the presence of recombinant IL-2 (rIL-2) was examined in age-matched groups of normal control subjects, steroid-free patients with glial tumors, steroid-dependent patients with glial tumors, and steroid-dependent patients with nonglial cerebral tumors. The results demonstrated that, when enriched T cell populations of all brain-tumor patients were stimulated with rIL-2 and phytohemagglutinin (PHA), there were no statistically significant differences between any groups. In contrast, when T cell populations were stimulated with mitogenic combinations of phorbol ester, calcium ionophore, and rIL-2, those from steroid-dependent patients with glial tumors had a significantly lower response than those from normal control subjects, suggesting that a population of T cells capable of responding to phorbol ester/ionomycin and not PHA stimulation is inhibited by corticosteroid therapy in glioma patients. In addition, T cells of four brain-tumor patient/age-matched control subject pairs were stimulated with either phorbol ester/ionomycin or PHA for 24 hours; three of the four patients expressed low-affinity IL-2 receptor levels as high or higher than their respective control subjects, suggesting that IL-2 receptor expression in these patients may be quantitatively normal once the T cell number is corrected. Taken together, these results show that the decreased PHA responsiveness that has been previously reported in lymphocytes of glioma patients is not due to a cellular abnormality within the potentially responsive cells, but rather reflects the reduced proportion of T cells within their peripheral blood which, as a consequence, reduces the level of IL-2 production attained upon activation.

Treatment of recurrent malignant glioma by repeated intracerebral injections of human recombinant interleukin-2 alone or in combination with systemic interferon-alpha. Results of a phase I clinical trial

Nine patients with a recurrent malignant glioma were treated with repeated intracavitary or intracerebroventricular injections of human recombinant interleukin-2 (rIL-2) alone or in combination with systemic interferon-alpha (IFN-alpha). Five patients received only rIL-2 and four were treated with rIL-2 plus subcutaneous injections of IFN-alpha. Therapy was administered on a Monday, Wednesday, Friday schedule for up to 10 weeks, beginning with a dose of 10,000 IU rIL-2/injection. Doses were escalated every two weeks until some toxicity was apparent. The maximum amount of rIL-2 any one patient in this group received was 580,000 IU. Patients on combination immunotherapy were held at an rIL-2 dosage of 10,000 IU while IFN-alpha, which began at 3 million IU, was escalated every other week up to 18 million IU/dose. They were then held at that IFN-alpha dosage and rIL-2 was increased to 50,000 IU. The total amount of rIL-2 and IFN-alpha any one in this group received was 510,000 IU and 417 million IU, respectively. Repeated injections of 10,000 IU rIL-2 were well-tolerated by all nine patients and no change in their functional status was seen. At doses at 50,000 IU rIL-2, increased edema around the tumor cavity was observed by MRI/CT scand in 3/5 patients and clinical side-effects in the form of somnolence and headache along with some morbidity specifically associated with tumor location were also seen. Patients receiving rIL-2+ IFN-alpha showed progressive fatigue, muscle weakness, and occasionally nausea. Two of these patients showed increased peritumoral edema on MRI/CT scan.(ABSTRACT TRUNCATED AT 250 WORDS)

Appearance of cytokine-associated central nervous system myelin damage coincides temporally with serum tumor necrosis factor induction after recombinant interleukin-2 infusion in rats

Endogenous tumor necrosis factor (TNF) activity, assessed by L-929 fibroblast bioassay, was determined in serum samples from rats infused intravenously with recombinant interleukin-2 (rIL-2) or rIL-2 vehicle. Parallel studies of cerebral ultrastructure were conducted in additional rats, comparably infused. Rats received rIL-2 or vehicle either one time only or 3 times daily for 3 days. TNF activity was assessed at 2, 4, and 8 h after the single or final infusion. Rats employed for ultrastructural studies were sacrificed at 4 h after the single or final infusion. Every rIL-2-infused rat exhibited unusual abnormalities of axonal ultrastructure, identical to those previously described after in vitro TNF application to living spinal cord slices. Serum samples drawn during and after the development of axonal changes revealed significantly elevated circulating TNF activity. Controls exhibited neither TNF activity nor altered axons. These studies demonstrate that, following rIL-2 infusion in rats, endogenous TNF circulates at elevated levels during the development of rIL-2-related central nervous system abnormalities similar to those produced in vitro by recombinant TNF. Whether rIL-2-induced circulating TNF is causally-related to the observed myelin damage remains to be determined but merits further investigation, particularly since blood-brain barrier function has been shown to be compromised following rIL-2 infusion.

A comparison of serum-free media for the support of in vitro mitogen-induced blastogenic expansion of cytolytic lymphocytes

The high cost and potential dangers of including human AB serum in incubation media used to expand lymphocyte populations in vitro for adoptive immunotherapy have stimulated efforts to develop defined media which can support both the expansion and induction of lymphocytes with tumor cytolytic activity in the absence of serum. Lymphocyte proliferation following exposure to either PHA or the combination of phorbol 12,13-dibutyrate (PDBu) and the calcium ionophore, ionomycin, was evaluated. Although the media tested, X-Vivo 10, HB-104, AIM V, and HL-1, supported the generation of comparable levels of LAK activity after 3-5 days incubation with 10(3) U human recombinant interleukin-2 (rIL-2)/ml, there were striking differences in the ability of each medium to support mitogenically stimulated lymphocytes in the absence of serum, with cells in AIM V and X-Vivo 10 showing the highest levels of DNA synthesis. In long-term cultures (17 days) of blood MNC stimulated by PDBu and ionomycin, X-Vivo 10 and HB-104 yielded the greatest numbers of cells. The addition of 2% AB serum greatly enhanced the ability of each medium to support cell proliferation to equivalent maximum levels. The results indicate that while all four serum-free media were suitable for lymphocyte culture and support the development of LAK activity, they differ in their capacity to support expansion of lymphocyte populations in response to polyclonal mitogenic activation. This latter characteristic should be considered before choosing a particular serum-free formulation as its constituents may affect mechanistic interpretations regarding signal transduction events.

Acute effects of human recombinant tumor necrosis factor-alpha on the cerebral vasculature of the rat in both normal brain and in an experimental glioma model

The effects of intravenous (IV) infusion of human recombinant tumor necrosis factor-alpha (rTNF-alpha, Cetus) on normal brain and malignant glioma in rats were examined. Twelve Fischer 344 rats were given either a single injection of 10(6) U rTNF-alpha or injections of 5 x 10(5) U rTNF-alpha for three days. One day post-rTNF-alpha injection(s), rats were injected IV with horseradish peroxidase (HRP) to determine blood-brain barrier (BBB) breakdown and, one hour later, were perfused with an aldehyde fixative and processed for histologic examination. Treatment of normal rats with rTNF-alpha by either dosage or schedule caused no remarkable histopathologic changes in the brain and no alteration in BBB integrity. Human glioma models were produced by intracerebal inoculation of 10(4) syngeneic RT-2 glioma cells into the right parietal lobe of 30 rats. Animals received single IV injections of 10(6) U human rTNF-alpha or its excipient (TNF-E) as above on day 3, 7, or 10 post-tumor inoculation or multiple injections of 5 x 10(5) U rTNF-alpha beginning on day 7, 10, or 12 post-tumor inoculation. With a single IV injection of either rTNF-alpha or its excipient, 3-day models showed a similar pattern of HRP extravasation limited to the extracellular space of the tumor inoculation site. In 7-day models treated with a single IV injection of rTNF-alpha or TNF-E, HRP extravasated throughout the tumor, but did not exceed peritumoral margins. In 10-day models treated with a single injection of TNF-E, HRP was found only in the tumor and immediate peritumoral regions while rTNF-alpha-treated rats showed more extensive areas of BBB breakdown with HRP evident throughout the entire right hemisphere and extending via the corpus callosum into the contralateral hemisphere. Pericapillary halos were also evident around the small blood vessels within the edematous areas of the corpus callosum. Within tumors, hemorrhagic necrosis and adherence of neutrophils to vessels was observed only in animals treated with rTNF-alpha at 10 days post-tumor inoculation. Multiple IV injections of rTNF-alpha in 7 and 10-day models triggered widespread hemorrhagic necrosis, neutrophil adherence and infiltration in the tumor. There was also extravasation and diffusion of HRP from the site of glioma into the contralateral hemisphere. Twelve-day models treated with multiple rTNF-alpha injections, in addition, showed irregular luminal surfaces and gaps between adjacent endothelial cells of tumor vasculature.(ABSTRACT TRUNCATED AT 400 WORDS)

Cerebral vasomotor responses after recombinant interleukin 2 infusion

The effects of systemic human recombinant interleukin 2 (rIL-2) infusion upon both the vasoconstrictor effect of hypocapnia and the endothelium-dependent vasodilator effect of acetylcholine (Ach) were examined in anesthetized rats equipped with cranial windows. Prior to the functional studies, each of six animals received an i.v. infusion of rIL-2 (6 x 10(5) IU/kg) every 8 h for 3 days. At the same time, six control animals received infusions of equivalent volumes of sterile water. Eight h after the final infusion, each animal was anesthetized and equipped with a cranial window for the observation of pial arterioles overlying the left frontoparietal cortex. Pial arteriolar diameters were measured before and after the topical application of Ach which in normal cerebral arterioles elicits the release of endothelium-dependent relaxing factor, causing vasodilation. When arteriolar diameters returned to base line, they were measured again both before and during hyperventilation-induced hypocapnia. Following functional assessments, these same pial vessels were processed for study by transmission electron microscopy to determine if any observed functional changes correlated with morphological abnormality. Results of the statistical analyses suggested that normal Ach-induced endothelium-dependent vasodilation was absent in the rIL-2-infused group. Additionally, these animals exhibited reduced reactivity to the vasoconstrictive effects of arterial hypocapnia. The control group exhibited normal responsiveness to both Ach and hyperventilation. Ultrastructural studies revealed occasional morphological alterations of both vascular smooth muscle and endothelial cells in some vessels of rIL-2-infused animals but not in controls. These data suggest that repeated systemic rIL-2 infusion results in altered vasomotor responsiveness within the cerebral microcirculation. The data also suggest that the observed vasomotor changes are not always accompanied by overt morphological alterations of either endothelial or smooth muscle cells.

Immunotherapy for malignant glioma using human recombinant interleukin-2 and activated autologous lymphocytes. A review of pre-clinical and clinical investigations

Over the past few years, we and a number of other groups have conducted laboratory experiments and clinical trials of human recombinant interleukin-2 (rIL-2) alone or in combination with autologous 'activated' lymphocytes expressing in vitro tumoricidal activity in order to define toxicity and indicate its potential efficacy in patients with high-grade glioma. Because high rIL-2 concentrations can be attained with considerably less toxicity than with a systemic approach, all of the clinical trials, to date, have chosen a direct route; injecting lymphokine and cells into tumor tissue, the cystic cavity remaining after tumor excision, and/or neural parenchyma surrounding the site of tumor excision. While the rIL-2 therapies, as they have been applied in animal glioma models and patients, are safe, cerebral edema around the site of treatment has been a consistent finding. We have also seen, however, that steroid medications used by patients to control their cerebral edema may depress the anti-tumor activity of rIL-2 by depressing the capacity of lymphocytes to develop normal LAK activity. Although none of the immunotherapies involving rIL-2 have produced cures, the fact that sustained clinical responses have been reported, suggests that such therapies may slow a recurrence of tumor at the site of treatment. Efforts to improve outcome from rIL-2--based immunotherapies for malignant glioma are continuing with manipulation of rIL-2 dosing and scheduling and also with combinations of rIL-2 and other recombinant cytokines.

Low-abundance 32-kilodalton nuclear protein specifically enriched in the central nervous system

Recently, a low-abundance nuclear protein, p32/6.3, has been identified in brain tissue (Egle and Shelton: Journal of Biological Chemistry 261:2294-2298, 1986). Using a Western blot procedure, we describe its distribution in the nervous system, determine its relative enrichment in brain versus liver, kidney, and certain other tissues, and describe an isolation procedure from brain. Selective enrichment occurs in basal ganglia, diencephalon, hippocampus, cerebellum, brainstem, spinal cord, and cerebral cortex but not in retina, dorsal root ganglia, and sympathetic ganglia. Thus, enrichment is limited to areas of the central nervous system. p32/6.3 appears to be preferentially enriched in neurons, because in bulk-isolated fractions from rat grey matter it is more abundant in neuron-enriched fractions than in astrocyte-enriched fractions. p32/6.3 is approximately 20-fold more concentrated in an insoluble nuclear protein or matrix fraction from forebrain than from kidney, liver, adrenal gland, or retina. This degree of enrichment is an ancient trait, detectable in the chicken as well as mammals.

In vitro lymphocyte proliferation induced by radio-frequency electromagnetic radiation under isothermal conditions

Whole human blood was exposed or sham-exposed in vitro for 2 h to 27 or 2,450 MHz radio-frequency electromagnetic (RF) radiation under isothermal conditions (i.e., 37 +/- 0.2 degrees C). Immediately after exposure, mononuclear cells were separated from blood by Ficoll density-gradient centrifugation and cultured for 3 days at 37 degrees C with or without mitogenic stimulation by phytohemagglutinin (PHA). Lymphocyte proliferation was assayed at the end of the culture period by 6 h of pulse labeling with 3H-thymidine (3H-TdR). Exposure to radiation at either frequency at specific absorption rates (SARs) below 50 W/kg resulted in a dose-dependent, statistically significant increase of 3H-TdR uptake in PHA-activated or unstimulated lymphocytes. Exposure at 50 W/kg or higher suppressed 3H-TdR uptake relative to that of sham-exposed cells. There were no detectable effects of RF radiation on lymphocyte morphology or viability. Notwithstanding the characteristic temperature dependence of lymphocyte activation in vitro, the isothermal exposure conditions of this study warrant the conclusion that the biphasic, dose-dependent effects of the radiation on lymphocyte proliferation were not dependent on heating.

Glioma proliferation modulated in vitro by isothermal radiofrequency radiation exposure

Isothermal (37 +/- 0.2 degrees C) exposure of glioma cells (LN71) for 2 h to 27 or 2450 MHz continuous-wave radiofrequency (RF) radiation in vitro modulated the rates of DNA and RNA synthesis 1, 3, and 5 days after exposure. The alterations indicate effects on cell proliferation and were not caused by RF-induced cell heating. The dose response for either frequency of the radiation was biphasic. Exposure to specific absorption rates (SARs) of 50 W/kg or less stimulated incorporation rates of tritiated thymidine (3H-TdR) and tritiated uridine (3H-UdR), whereas higher SARs suppressed DNA and RNA synthesis. Statistically significant time-dependent alterations were detected for up to 5 days postexposure, suggesting a kinetic cellular response to RF radiation and the possibility of cumulative effects on cell proliferation. General mechanisms of effects are discussed.

Sterile abscesses in glioma patients treated by intraparenchymal injection of lymphokine-activated killer cells and recombinant interleukin-2: case reports

Earlier, we conducted Phase I clinical trials to determine any acute toxicity of adoptive immunotherapy with intralesional injections of autologous lymphocytes expressing lymphokine-activated killer (LAK) activity and recombinant interleukin-2 (rIL-2) in patients with malignant glioma. Within six weeks of craniotomy and intralesional injection of autologous LAK cells plus rIL-2, 3 of 29 patients demonstrated a decline in clinical status and evidence on computed tomographic and magnetic resonance imaging scans of edema and mass of unknown character at the site of previous surgery and immunotherapy. Craniotomy was performed to remove the tissue and reduce intracranial pressure. Microscopic examination of the excised material indicated no new tumor growth within the resected mass, but rather that the tissue had the histological characteristics of a chronic sterile abscess including necrosis, fibrosis, and influx of inflammatory cells. Factors that may have contributed to this reaction in the 3 patients were age, Karnofsky score, the extent of tumor excision, and immune status. All 3 had also been treated with greater than average numbers of rIL-2 activated lymphocytes that demonstrated significant in vitro LAK activity. The results suggest that in patients whose clinical status is good and who are not immunosuppressed by corticosteroids, the dose-limiting toxicity of intraparenchymal immunotherapy with LAK cells plus rIL-2 for glioma may be related to the total, absolute number of activated cells injected, and this toxicity develops over time and is manifested by development of a sterile abscess.

Histopathological and blood-brain barrier changes in rats induced by an intracerebral injection of human recombinant interleukin 2

Adoptive immunotherapy utilizing human recombinant interleukin 2 (rIL-2) in conjunction with lymphokine-activated killer cells has shown some efficacy in the treatment of various types of cancers, particularly renal carcinoma and melanoma. Intravenous administration of rIL-2, with or without lymphokine-activated killer cells, produces a variety of serious side effects and approximately one-third of the patients experience a decrease in neurological status. Our previous investigations in animals have indicated that a single intravenous injection of rIL-2 can compromise the integrity of the blood-brain barrier (BBB). The present study examined the histopathological effect and BBB changes in rats which occur after a single intracerebral injection of rIL-2, its excipient, or saline into the parietal lobe. Animals were killed at various intervals up to 8 days (1 hour after intravenous injection of horseradish peroxidase), and the brain tissue was sectioned and processed for light microscopy. All animals showed increased cerebrovascular permeability for horseradish peroxidase due to traumatic BBB disruption at 4, 12, and 24 hours after injection. Extravasation of horseradish peroxidase persisted at 3 and 8 days only in animals injected with rIL-2. Injections of rIL-2 led to an increased leukocytic infiltration into the injection site, perivascular cuffing, and localized edema by 24 hours, which continued to increase over the 8-day study period. These results suggest that a single injection of human rIL-2 into the brain of rats induces an influx of leukocytes into the brain and may contribute to the cellular events that perpetuate a trauma-induced compromise in the integrity of the BBB.

Nonspecific cytotoxicity of recombinant interleukin-2 activated lymphocytes

The administration of interleukin-2 (IL-2) and lymphokine activated killer (LAK) cells to patients with advanced metastatic cancer has yielded encouraging results. The purported ability of LAK cells to be discriminatively tumoricidal, thus sparing normal host tissue, represents a major advance over conventional chemotherapy. However, IL-2 adoptive immunotherapy results in dose-limiting toxicity characterized by weight gain, dyspnea, ascites, and peripheral-pulmonary edema suggestive of a vascular leak syndrome. It is unclear whether the observed toxicity is directly related to IL-2 and/or LAK cells. The authors examined the cytolytic nature of human LAK cells against human endothelial, epithelial, and fibroblast cell lines. Bovine endothelial cells also were studied. Using a 51Cr release assay, the cytolytic potential, time course, and effect of reactive oxygen intermediate inhibitors were studied. LAK cells were uniformly toxic against all cell lines, in contrast to high dose rIL-2 and excipient. Significant cytolysis was observed within 30 minutes and increased over the first 2 hours of LAK cells coming in contact with target cells. Reactive oxygen intermediate inhibitors did not reduce cytolytic activity. The authors thus found human LAK cells to be rapidly cytolytic against a variety of human and bovine cell lines. This cytolysis was independent of reactive oxygen intermediates.

Interleukin-2 modulates the expression of lymphocyte function-associated antigen-one (LFA-1) and p150,95 during the generation of lymphokine-activated killer (LAK) cells

Lymphocyte function-associated antigen-one (LFA-1), Mac1 and p150,95 represent a family of heterodimeric cell surface molecules with a common beta subunit and distinct alpha subunits. LFA-1 is known to be functionally important in cell-cell interactions between immune cells. In the present study, a mouse monoclonal antibody (mAb), RH1-38, which recognizes an epitope on the beta-chain of LFA-1 was used to study the function and expression of LFA-1 on lymphokine-activated killer (LAK) cells. This mAb has been shown previously to block, in the absence of complement, cytolytic activity mediated by natural killer (NK) cells, cytotoxic T lymphocytes (CTL), and a monocyte-like cell (phorbol diester-stimulated HL-60 cells). LAK cells were generated by culturing in vitro human peripheral blood lymphocytes (PBL) in the presence of human recombinant interleukin-2 (rIL-2), and cytotoxic activity was measured by a 51Cr-release assay using the human NK-resistant Daudi cell line. Addition of RH1-38 ascites supernatant, purified RH1-38 mAb, or F(ab')2 fragment of RH1-38 markedly reduced (>80) LAK cytolytic activity, whereas NS-1 (parent hybridoma) ascites supernatant, normal mouse IgG, and monoclonal anti-HLA had no effect on LAK-mediated killing. Equivalent inhibition of NK and CTL activity by purified RH1-38 required 10-100-fold more antibody. Appreciable inhibition occurred if the mAb was added up to 2 hr after LAK cells were mixed with targets. Indirect immunofluorescence flow cytometry and immunoprecipitation studies revealed that LFA-1 and p150,95 expression were dramatically enhanced in PBL populations cultured with rIL-2 compared with PBL cultured without rIL-2; Daudi cells expressed no detectable LFA-1 family heterodimers. Time-course experiments demonstrated that during culture of PBL in the presence of rIL-2, development of enhanced expression of LFA-1 and p150,95 correlated closely with LAK cytolytic activity. These studies (i) demonstrate that LFA-1 and/or p150,95 are functionally important effector cell surface molecules expressed by LAK cells and that some homology to NK and CTL mechanisms of cell-mediated lysis may exist; and (ii) suggest that enhanced LFA-1 and/or p150,95 expression are important for development of the fully differentiated LAK effector cell in the presence of rIL-2.

Cardiorespiratory and cellular changes with interleukin 2 infusion in sheep

Recombinant interleukin 2 (rIL-2) administration, a new form of therapy for patients with far-advanced cancer, is associated with a "third space" syndrome, i.e., pulmonary edema, respiratory distress, and hypoxemia, which limits the dose and duration of treatment. To extend our knowledge regarding this toxicity, we established a sheep chronic lung lymph fistula model and measured hemodynamics, arterial blood gases, caudal mediastinal (lung) lymph flow (QL), and blood and lung lymph cellular changes before, during, and after (recovery) a 3-day continuous rIL-2 infusion (9 x 10(5) U/kg). Moderate systemic hypotension, mild pulmonary hypertension, and an increase in alveolar-arterial PO2 gradient was present on day 3 of rIL-2 infusion. QL increased from a base line of 1.9 +/- 0.2 to a maximum of 4.3 +/- 1.1 ml/15 min on day 3 of rIL-2 infusion. At no time was there a change in lymph-to-plasma protein ratio. The leukocyte count increased significantly to 16.1 +/- 4.5 x 10(3) cells/mm3 at recovery day 1. The percentage of blood lymphocytes decreased significantly by day 1 of rIL-2 infusion, returned to base-line levels on day 3, and significantly increased on day 2 of recovery. Lung lymph lymphocytes decreased significantly on days 1 and 2 of rIL-2 infusion. There was a shift in their size; i.e., their area increased from 32 +/- 7 to 57 +/- 19 micron 2 (P less than 0.05) by day 2 of rIL-2 infusion. By day 1 of recovery, lung lymph lymphocyte counts increased significantly.(ABSTRACT TRUNCATED AT 250 WORDS)

Corticosteroids inhibit the generation of lymphokine-activated killer activity in vitro

In phase-I clinical trials of adoptive immunotherapy using lymphokine-activated killer (LAK) cells plus recombinant interleukin-2 (rIL-2) (Cetus) for the treatment of malignant glioma, we observed that blood mononuclear cells (MNC) from patients dependent on dexamethasone for management of cerebral edema produced substantially less LAK activity as compared to MNC of normal blood donors or glioma patients not receiving steroid therapy. Therefore, we examined the in vitro effects, brought about by therapeutically attainable concentrations of various corticosteroids, on the proliferative response, production of gamma interferon (IFN-gamma), and induction of LAK activity from blood MNC of normal donors. Incubation in media containing rIL-2 (1000 U/ml) with either dexamethasone, hydrocortisone, methylprednisolone, or prednisolone profoundly affected all of these parameters. First, while 0.01 micrograms/ml of either dexamethasone or hydrocortisone caused a slight enhancement of the mitogenic response of lymphocytes to phytohemagglutinin, a dose-dependent decline occurred as concentrations increased to 10 micrograms/ml. The addition of prednisolone and methylprednisolone elicited a dose-dependent inhibition of lymphocyte proliferation over the entire concentration range tested. At 0.1 microgram/ml or higher, dexamethasone, hydrocortisone, methylprednisolone and prednisolone significantly (P less than 0.02) inhibited the production of IFN-gamma: respectively 18.9%, 4.4%, 2.2%, and 12.3% of the IFN-gamma produced by MNC in the absence of steroids. All four corticosteroids inhibited the induction of LAK activity. Compared to MNC that had been incubated with 1000 U/ml rIL-2 alone, MNC cultured with rIL-2 and 10 micrograms/ml either dexamethasone or prednisolone demonstrated significantly lower cytotoxicity (P less than 0.05) for the natural-killer-cell-resistant cell line, Daudi. Culturing MNC with hydrocortisone had a more dramatic result, causing a significant decline (P less than 0.01) in lytic activity at both 1.0 micrograms/ml and 10 micrograms/ml, while incubation with methylprednisolone produced a significant drop (P less than 0.02) in LAK-mediated cytotoxicity at 0.1 micrograms/ml as well as 1.0 micrograms/ml and 10 micrograms/ml. When cytotoxicity was expressed as lytic units per million effectors, a dose-response decline in lytic activity was once again apparent, with hydrocortisone, methylprednisolone and prednisolone showing significant inhibition (P less than 0.05) at both 1.0 micrograms/ml and 10 micrograms/ml and dexamethasone at 10 micrograms/ml (P less than 0.01). These results indicate that corticosteroids commonly used in the management of cere

Intralesional infusion of lymphokine-activated killer (LAK) cells and recombinant interleukin-2 (rIL-2) for the treatment of patients with malignant brain tumor

Twenty patients with supratentorial, intracerebral lesions defined by computed tomographic scan or magnetic resonance imaging were treated by surgery and adoptive immunotherapy with lymphokine-activated killer (LAK) cells and recombinant Interleukin-2 (rIL-2, Cetus). Seventeen patients had glioblastoma, two had high-grade oligodendroglioma, and one patient had two metastatic sarcoma lesions. LAK cells were produced from blood mononuclear cells (MNC) obtained by 2 to 3 leukapheresis procedures and cultured (2.5 x 10(6) MNC/ml) 3 to 5 days with 1000 units rIL-2/ml. Although LAK cells could be produced from MNC of all patients, those taking steroids or with a low Karnofsky functional status generated, on average, suboptimal LAK cell activity. Age, sex, and serum anticonvulsant levels do not seem to influence a patient's ability to produce LAK cells in vitro. For therapy, cultured MNC (1-15 x 10(9] containing LAK cells were suspended in saline containing 10(6) units rIL-2 and injected into tissue surrounding the tumor cavity during craniotomy. For 3 days after their operations, patients received 10(6) units rIL-2 into the tumor cavity through an Ommaya reservoir. The treatment protocol was tolerated well by all patients, although they all experienced some degree of headache, fever, or lethargy that cleared within a few days of the last rIL-2 injection. When computed tomographic (CT) scans were obtained soon after treatment, areas of low density suggested a greater-than-normal extent of edema around the operative site. At the present time, CT scans indicate that the tumors of seven patients have recurred with an average disease-free interval of 25 +/- 6 weeks.(ABSTRACT TRUNCATED AT 250 WORDS)

Adoptive immunotherapy for recurrent glioblastoma multiforme using lymphokine activated killer cells and recombinant interleukin-2

Thirteen patients with recurrent glioblastoma were treated with adoptively transferred autologous lymphokine activated killer (LAK) cells and recombinant interleukin-2 (rIL-2). Patients' blood mononuclear cells (MNC) obtained by leukapheresis were cultured at 2.5 million MNC per ml for 3 to 5 days in media containing 1000 U rIL-2/ml. After incubation, the nonadherent MNC from all cultures (0.5-5 X 10(9] were combined and concentrated for infusion in 5 to 10 ml saline containing 10(6) U rIL-2. Nine patients received one injection of LAK cells and rIL-2 into the brain tissue immediately surrounding the tumor cavity during craniotomy for subtotal tumor removal (Group 1). On each of the 3 days after surgery, patients received boosters of 10(6) U rIL-2 delivered into the tumor cavity through a skin flap or via an Ommaya reservoir. Approximately 1 to 2 weeks after this series of injections, these patients were treated with a second cycle of LAK cells and rIL-2 injected into the tumor cavity using the reservoir. Four patients received both adoptive immunotherapy cycles by intracavitary injection (Group 2). In this relatively small patient pool, neither age, sex, Karnofsky score, treatment history, nor anticonvulsant and steroid dosage appeared to influence a patient's ability to make LAK cells. The therapy, itself, was well-tolerated by all patients although they all displayed symptoms of aseptic meningitis and increased intracranial pressure, i.e., headache, fever, malaise on the days of LAK cell and/or rIL-2 infusion. The therapy did not appear to have a significant impact on patient survival (mean, 30 weeks) especially for those patients with a high postsurgical tumor burden. As the therapy is safe, the authors believe its efficacy can best be tested in patients with a newly diagnosed or recurrent glioblastoma which lies in an area where a near-total resection is possible.

A comparison of the cardiopulmonary effects of continuous versus bolus infusion of recombinant interleukin-2 in sheep

The systemic administration of recombinant interleukin-2 (rIL-2) is used for the treatment of patients with far advanced cancer. However, treatment may be limited by a so-called "third space" syndrome. Whether these side effects are due to the total dose used or the method of administration is unclear. To define whether the continuous (Group 2) or bolus (Group 3) i.v. infusion of 9 x 10(5) units/kg rIL-2 over 72 h is associated with similar toxicities, we established a chronic sheep model and monitored changes in systemic and pulmonary vascular pressures, cardiac function, and gas exchange. At 72 h lung lymph flow, lymph/plasma protein ratios, lung histology, and extravascular lung water/dry lung weight were obtained. In both groups the infusion of rIL-2 resulted in an increase in high protein lung lymph flow, an increase in cardiac output, and a decrease in systemic vascular resistance. Large lymphoid cells were found by histology to be infiltrating the lung interstitium. In Group 2, in addition, there were mild pulmonary hypertension [pulmonary artery pressures increased from 14 +/- 5 to 22 +/- 6 mmHg (P less than 0.05)], systemic hypotension [81 +/- 7 compared to a baseline of 95 +/- 9 mmHg (P less than 0.01)], and worsening gas exchange. We conclude that a 72-h continuous or bolus infusion of equivalent doses of rIL-2 are associated with cardiopulmonary toxicity; however, pulmonary hypertension, systemic hypotension, and gas exchange are worse in animals receiving the continuous infusion.

Cardiopulmonary effects of recombinant interleukin-2 infusion in sheep

The systemic administration of recombinant interleukin-2 (rIL-2) with or without lymphokine-activated killer (LAK) cells, a new treatment for patients with advanced cancer, is associated with a presumed "third-space" syndrome. To further define the extent and time course of this toxicity, we established a chronic sheep model and monitored changes in systemic and central vascular pressures, cardiac function, and gas exchange during a 72-h continuous intravenous infusion of rIL-2 at a total dose of 5 (group 3) or 9 x 10(5) U/kg (group 4). At 72 h, caudal mediastinal lymph flow, histology, and extravascular lung water-to-dry lung weight ratio (EVLW/DLW) were obtained. During the rIL-2 infusion there was a dose-dependent significant decrease in systemic blood pressure and arterial Po2 and an increase in core temperature. In group 4, pulmonary arterial pressure increased from a base line of 13 +/- 5 to 21 +/- 6 mmHg (P less than 0.05). Lung lymph flow was significantly increased in groups 3 and 4 compared with animals receiving 0.9% NaCl or excipient infusions (groups 1 and 2). EVLW/DLW values were elevated in groups 3 and 4 (P less than 0.01). In animals receiving rIL-2, histological evaluation revealed a dose-dependent infiltration of lung tissue by lymphoblastoid cells that stained esterase negative. We conclude that rIL-2 infusion in doses comparable to those given to humans results in alterations in systemic and central hemodynamics, gas exchange, high-protein lung lymph flow, and infiltration of lymphoblastoid cells into the lung parenchyma.

Alteration of human lymphokine-activated killer cell activity by manipulation of protein kinase C and cytosolic Ca2+

We have examined the effects of protein kinase C (PK-C) stimulation and cytosolic Ca2+ elevation on the in vitro induction of non-histocompatibility-restricted tumoricidal activity from human peripheral blood lymphocytes. The tumor cytolytic activity, as well as the number of cells recovered from interleukin 2 (IL-2)-stimulated cultures, was enhanced by the addition of the PK-C stimulator, phorbol dibutyrate (PDBu), but not non-PK-C-activating phorbol ester analogues while the Ca2+ ionophore, ionomycin, did not significantly alter development of IL-2-induced tumor cytolytic activity nor enhance cell yield. Neither PDBu nor ionomycin, alone or in combination, induced tumoricidal activity. The addition of both PDBu and ionomycin to recombinant interleukin 2 (rIL-2)-exposed cultures produced a strong mitogenic response and high cell yield, although Daudi cell killing measured at Day 5 was completely abolished. This abrogation of lymphokine-activated killer cell activity was seen as early as 24 h following exposure to PDBu and ionomycin, reaching 50% following 2 days of exposure. When lymphocytes mitogenically expanded by primary exposure to PDBu and ionomycin and then washed free of these agents were further cultured with rIL-2 alone, proliferation continued, and substantial cytolytic activity for Daudi cells was induced. The development of this postexpansion cytotoxic activity was not dependent on the addition of exogenous rIL-2 during the primary cultures. Fractionation of cells into large granular lymphocytes and small T-lymphocytes indicated that only the large granular lymphocytes proliferate in response to rIL-2 alone. Both large granular lymphocytes and small T-lymphocytes proliferate in response to the addition of PDBu and ionomycin, and both populations of cells developed tumor cytolytic activity following removal of PDBu and ionomycin and subsequent culture in rIL-2. These data suggest that PK-C and Ca2+ signals play key roles in the regulation and/or proliferation of tumor cytotoxic lymphocytes or their precursors and that manipulation of those signals can be utilized to produce substantially more tumoricidal activity from lymphocyte populations than can be achieved with rIL-2 alone.

Blood-brain barrier dysfunction in cats following recombinant interleukin-2 infusion

The effects of systemic human recombinant interleukin-2 (rIL-2) infusion upon blood-brain barrier status and cerebral vascular ultrastructure were examined in cats. Each of eight animals received a single bolus i.v. infusion of rIL-2 (100,000 units/kg). Six control animals were infused with rIL-2 excipient only. Following a 1-h postinfusion survival time, the brain tissue of five rIL-2 infused and three excipient infused animals was processed and examined by light microscopy and electron microscopy for evidence of altered cerebrovascular permeability to systemically circulating horseradish peroxidase. The brain tissue of three additional rIL-2 infused animals and three excipient infused animals, sacrificed 4 h postinfusion, was examined at the light microscopic and electron microscopic levels for the presence of extravasated endogenous IgG. All animals infused with rIL-2 and four of six excipient infused animals showed increased cerebrovascular permeability to the probe used. Altered blood-brain barrier permeability, when present, was recognized in multiple loci throughout the brain, being most prominent within white matter regions. Horseradish peroxidase and IgG were observed within perivascular basal laminae and within the interstices of the brain parenchyma. Numerous endothelial lesions were observed as was flooding of endothelial cytoplasm by horseradish peroxidase or IgG. Every animal studied, regardless of permeability status, showed, within the perivascular brain parenchyma, numerous disrupted neuronal and glial processes as well as expanded intercellular spaces. This study suggests that a single systemic infusion of rIL-2 profoundly alters blood-brain barrier integrity and cerebrovascular morphological integrity. The data also suggest that some of the observed cerebrovascular effects of systemic rIL-2 infusion are due to components of the vehicle for rIL-2.

Increase of rat pulmonary microvascular permeability to albumin by recombinant interleukin-2

Immunotherapy with the lymphokine interleukin-2 (IL-2), with or without lymphokine activated killer (LAK) cells, offers a new approach to the treatment of solid tumors. Unfortunately, most patients receiving IL-2 and LAK cells develop a "third space syndrome" from a presumed generalized increase of vascular permeability. We have investigated the role of IL-2 on lung fluid balance, by measuring changes in lung water and albumin intake. Rats were injected with IL-2 500,000 U i.p. three times a day for 1 to 4 days. At the completion of the injections, lungs were isolated and perfused, and total lung water (TLW) and 125I-albumin uptake were measured. After 1 day of injections, TLW increased from 4.90 +/- 0.14 to 5.57 +/- 0.34 ml/g dry lung and albumin uptake nearly doubled from 0.47 +/- 0.08 to 0.91 +/- 0.28 cm3/s/g dry lung X 10(-3). Longer injection periods increased both TLW and albumin uptake further. After 2 days, TLW and albumin uptake were also significantly increased by 160,000 U i.p. three times a day, but not by 40,000 or 10,000 U. To eliminate possible contributions to increased permeability by (a) LAK cells generated in vivo, or (b) circulating leukocytes, we isolated lungs from normal rats and perfused them for 5 min with a cell-free perfusate containing IL-2 (2, 10, or 5 X 10(-3) U/ml) excipient or 0.9% NaCl placebo. TLW was similar in all groups, but albumin uptake was significantly increased by 10,000 and 50,000 U/ml (0.94 +/- 0.15 and 0.82 +/- 0.16 cm3/s/g dry lung X 10(-3), respectively), but not by 2,000 U/ml. We conclude that lung microvascular albumin permeability is increased following administration of IL-2 in vivo and in vitro. We suggest that LAK cells are not required for the initiation of increased permeability and that IL-2 may have some direct effect on the pulmonary microvasculature.

Leukoregulin inhibits the growth of human glioblastoma in vitro

Growth of cultured human glioblastoma cells was profoundly inhibited by concentrated lymphokines prepared from mitogen-activated blood mononuclear cells of normal donors. Cloning efficiency of glioma cells and their absolute number were decreased as well. Partially purified leukoregulin, free of lymphotoxin, tumor necrosis factor and gamma-interferon, similarly suppressed DNA synthesis and clonogenicity. The decrease in absolute numbers of tumor target cells indicated that leukoregulin was directly cytolytic as well as cytostatic for human glioblastoma cells. Our data indicate that leukoregulin is at least one of the factors produced by activated lymphocytes which inhibits the proliferation of human glioblastoma in vitro.

Mitogen-activated lymphocytes of normals and glioma patients produce factors with anti-glioblastoma activity in vitro

Human glioblastoma cell lines showed profound suppression of both DNA and RNA synthesis when exposed to supernatants (SNs) of mitogen-activated blood mononuclear cells. Cloning efficiency of these glioma cells also decreased 10- to 500-fold. In monolayer cultures, growth inhibition was evident within 12 h of adding SN and peaked at 24 h. A decrease in absolute cell number was evident by 72 h. The inhibitory effect of SNs, however, was not permanent as more cells entered S-phase when SN-treated cultures were refed with fresh medium (without SN). The factor(s) responsible for this inhibitory activity was a product of lymphocytes and was produced in comparable amounts by cells of normal blood donors and patients with glioma. The compromised immunological status of glioblastoma patients did not influence their capacity to produce cytostatic lymphokines.

Hairy cell leukemia: kinetics and intercellular relationships of cells in leukemic colonies grown in a semisolid medium

We examined cellular relationships and cytokinetics of hairy cells in colonies formed in an in vitro cloning system. Cells in small colonies and at the periphery of larger ones were separated by wide, irregular intercellular spaces. Cells in the core of large colonies were elaborately intertwined by their cytoplasmic processes and so densely packed that their intercellularity was greatly reduced. Cell labeling with 3H-thymidine revealed indices ranging from less than 1% to 35%. The combination of autoradiography with a stain for tartrate-resistant acid phosphatase showed that the enzyme was not expressed by cells in S-phase. The cellular relationships of hairy cells in colonies grown in this system closely mimic those of their in vivo counterparts in the spleen and bone marrow.

Hairy cell leukemia. Ultrastructural and cytochemical evaluation of leukemic colonies grown in a semi-solid medium

We examined the fine structure and enzymatic activity of cells composing colonies grown from blood and/or spleen of eight patients with hairy cell leukemia. Mononuclear cells (MNC) were plated over an agar layer in a medium containing methylcellulose and leukocyte-conditioned medium. After 7-10 days incubation colonies were harvested for cytologic study. Colony cells possessed a euchromatic nucleus with an occasional nucleolus. Their cytoplasm contained a prominent Golgi region, numerous mitochondria and small vesicles, many short strands of rough endoplasmic reticulum (RER) and an infrequent phagosome. Well-developed ribosome-lamella complexes and what may have been their intermediate forms appeared in colony cells from three patients. Strong activity for tartrate-resistant acid phosphatase, localized in the RER, nuclear envelope and some Golgi vesicles, was evident in 50-95% of all colony cells. Our results indicate that a high proportion of MNC forming colonies in this culture system maintain the characteristic morphology and cytochemical activity of hairy cells.

Effects of 13-cis retinoic acid and Ara-C on differentiation and proliferation of non-promyelocytic acute myelogenous leukemia

An alternative to a cell-kill strategy for eradication of acute myelogenous leukemia, is to restore normal differentiation. Vitamin A derivatives demonstrate differentiation-inducing activity both in vitro and in vivo on promyelocytic leukemic cells. We tested the ability of 13-cis retinoic acid to reduce proliferation and induce differentiation in 10 samples from patients with acute non-promyelocytic leukemia. DNA synthesis and leukemia colony formation were affected to varying degrees by a prolonged exposure to the vitamin A compound. Morphologically and cytochemically no differentiation was determined either after 48 h in suspension cultures or 7 additional days in semi-solid cultures. Alkaline leukocyte phosphatase, a biochemical marker of differentiation, was significantly increased in five samples. DNA synthesis in these samples was significantly reduced as compared to samples failing to express alkaline leukocyte phosphatase following 13-cis retinoic acid treatment. DNA synthesis of these same 5 samples was also strongly inhibited by Ara-C. Expression of alkaline leukocyte phosphatase following 13-cis retinoic acid exposure may be a useful indicator for cells amenable to 13-cis retinoic acid or Ara-C treatment.

Cellular aggregates in bone marrow cultures of patients with acute myeloid leukemia

We describe the incidence and morphology of cellular aggregates which may develop in 8 day bone marrow (BM) cultures of patients with acute myeloid leukemia (AML). Aggregates formed in at least one BM culture from 50% (20/39) of the AML group. They developed irrespective of the patient's status (i.e. stages M1-M4), FAB type, and presence of colony stimulating factor (CSF). All aggregates were composed of macrophages, plasma cells, and cells of the myelocyte series surrounding a core of adipocytes and collagen fibrils. The percentage of blasts and promyelocytes in the plated BM aspirate governed the final composition of the aggregate. Patients in Stages M3 or M4 with FAB types M1 or M2 formed aggregates with a high proportion of myelocytic cells; aggregates of all other AML patients were composed predominantly of macrophages and plasmacytes. Aggregates appeared to form as a result of attraction of cells in the medium toward the stroma cell core. Furthermore, the development of aggregates in the absence of exogenous CSF, suggested that stromal cells excreted a factor with CSF-like activity. The results indicate that cellular aggregates in AML-BM cultures reflect the important role of BM stroma in creating microenvironments which enhance the development of hemopoietic stem cells.

Ultrastructural histopathology of experimental Haemophilus influenzae type B meningitis in the infant rat. II. Phagocytosis and lysis of microorganisms by leptomeningeal leukocytes

We examined the events associated with phagocytosis, lysis and digestion of Haemophilus influenzae type b (Hib) by subarachnoid leukocytes in infant rats with experimental Hib meningitis. In early stages of infection, large numbers of bacteria were attached to the surfaces of neutrophils and macrophages invaded the subarachnoid space and actively ingested Hib. The bacteria, coccobacillary in shape with an approximate length of 1.0 micrometers and 0.3 micrometer in width, were interiorized after fusion of leukocyte microplicae which had arisen around them. Ingested Hib were sequestered within large, membrane-bound vacuoles containing five or more microbes. Following the fusion of primary lysosomes with the membrane of the phagocytic vacuole, bacteria were lysed and degraded. In later stages of infection, macrophages possessed large numbers of inclusions containing extensively digested Hib and myelin figures. Histochemical analysis of subarachnoid leukocytes revealed that macrophages actively synthesized acid phosphatase and that this enzyme aided in the digestion of phagocytosed bacteria. Peroxidase was also demonstrated within phagocytic vacuoles of neutrophils. Our results suggest that subarachnoid macrophages and neutrophils actively lyse and digest ingested Hib through the direct action of their hydrolytic enzymes.

Ultrastructural histopathology of experimental Haemophilus influenzae type B. Meningitis in the infant rat. I. Leukocytes of the spinal leptomeninges

We examined the origin, nature and role of cellular defense mechanisms in experimental Haemophilus influenzae type b (Hib) meningitis in the infant rat using ultrastructural techniques. An extensive inflammatory exudate composed of granulocytes, lymphocytes and macrophages was observed on the leptomeninges of all animals with meningitis. At 1-3 days following Hib-inoculation, neutrophils were the major leukocytic element within the exudate while at 7-9 days the leukocyte population was dominated by macrophages. Irrespective of day of inoculation, leukocytes were observed undergoing diapedesis through the thin-walled blood vessels of the subarachnoid space and pial connective tissue, a phenomenon which suggested that the cellular elements composing the inflammatory exudate originated directly from the systemic circulation. Only neutrophils and macrophages demonstrated phagocytosis of free bacteria in the cerebrospinal fluid. The presence of plasma cells suggests that antibody to Hib may be synthesized locally within the subarachnoid space. Furthermore, cell-to-cell contacts among leukocytes may also contribute to the initiation and maintenance of the humoral immune response to Hib.

The median eminence in normal, ovariectomized, and ovariectomized-estradiol-treated hamsters: an ultrastructural study

In an effort to define more clearly the effect various plasma concentrations of estrogen have on the morphology and function of tanycytes, the present investigation examined the median eminence (ME) of normally cycling, ovariectomized, and ovariectomized-estradiol-treated hamsters. In normally-cycling animals, when endogenous estrogen was at its highest level (day 4 or proestrus), numerous microappendages arose from the luminal surfaces of tanycytes located in the ventrolateral region of the ME. Large blebs (1.0-5.0-micrometers diameter), miniblebs (1.0-micrometer diameter), and microvilli dominated the surfaces of these cells. Large blebs appeared to have been formed by the coalescence of several miniblebs and were composed of cytoplasmic ground substance devoid of organelles. The peduncular shape of many of these blebs suggested their involvement in an apocrinelike secretion by the tanycyte. When endogenous estrogen levels were low (day 1 of the estrous cycle), the tanycytes of normally cycling hamsters possessed slightly fewer microappendages. Following ovariectomy, large blebs were nearly absent from the luminal surfaces of tanycytes, and the number of miniblebs and microvilli were also greatly reduced. Subcutaneous injections of 17-beta estradiol benzoate restored the large blebs to the tanycyte surface. The number and variety of tanycytic microappendages in these animals resembled those in normally cycling hamsters on day 4 of the estrous cycle. The present study demonstrates that tanycytes of the hamster ME are sensitive to estrogen and vary in their morphology in relation to the animal's reproductive status. These changes in tanycyte morphology can be correlated directly to functions of absorption (microvilli) and secretion (blebs). The sensitivity of tanycytes to estrogen suggests that these cells may also play a role in the hypophyseal-ovarian feedback mechanism.