Interleukin-2 enhances the depressed natural killer and cytomegalovirus-specific cytotoxic activities of lymphocytes from patients with the acquired immune deficiency syndrome

Defective interleukin 2 production and responsiveness in human pulmonary tuberculosis

Patients with newly diagnosed, pulmonary tuberculosis had a tuberculin-specific defect in IL-2 production. Mean PPD-induced IL-2 activity was 81.2% lower in patients as compared with healthy tuberculin reactors. PPD-induced expression of T cell IL-2 receptors was 5.9 times less in peripheral blood mononuclear cells of patients with tuberculosis as compared with healthy tuberculin reactors. Furthermore, purified IL-2 failed to correct PPD-induced blastogenesis in patients. Suppression by adherent cells was operative in one group of patients; adherent cell depletion increased their T cell production of IL-2 7.2-fold. A second group of patients with low IL-2 production did not have suppressor adherent cells and were clinically distinct, with more extensive disease on chest x ray. The basis for low IL-2 production in such individuals is unknown. Disordered regulation of IL-2 metabolism may be a key feature in the depressed cellular immune response of tuberculosis.

High frequency of immune dysfunctions in asbestos workers and in patients with malignant mesothelioma

We have examined the primary immune responses, the numbers of total T (T11+) cells, T-helper (T4+) cells, T-suppressor (T8+) cells, and natural killer (NK) (Leu7+) cells, in 118 healthy control subjects and compared the data to those obtained from 20 patients with clinically diagnosed malignant mesothelioma and 375 long-term asbestos workers without neoplasia. The absolute numbers of total T (T11+) and T-helper (T4+) cells were normal in asbestos workers without neoplasia but were significantly reduced in patients with mesothelioma. T-suppressor (T8+) cells, on the other hand, remained unchanged in the patients but were significantly elevated among the asbestos workers. This resulted in a marked reduction in T-helper (Th) to T-suppressor (Ts) ratios in mesothelioma patients and in asbestos workers. Seventy percent of the mesothelioma patients (14 of 20) had significantly depressed NK-cell activity which could be augmented but not normalized by coincubation in patients' peripheral blood lymphocytes (PBL) with interferon (IFN). Among the asbestos workers three distinctive subgroups could be identified: heightened (H-NK), normal (N-NK), and low (L-NK) NK activity. The NK activity of the L-NK group could be stimulated but not normalized by coincubation with IFN, a finding closely resembling that in malignant mesothelioma patients. Phenotyping of the circulating NK cells revealed a unique Leu7+ subset in increased numbers with a brightly fluorescent property in stable mesothelioma patients with relatively stable or slowly progressive disease and in more than 30% of the asbestos workers.(ABSTRACT TRUNCATED AT 250 WORDS)

Induction of T-cell proliferation and enhancement of NK activity by supernatants from Con A-stimulated human peripheral blood mononuclear cells: a new lymphokine

Supernatants from human peripheral blood mononuclear cells activated by Con A contain a factor(s) that stimulates blastogenic activity of normal human peripheral blood mononuclear cells. This Con A supernatant (CAS) contains stimulatory activity for E-rosette positive lymphocytes (T cells) and requires adherent cells for stimulation of T-cell proliferation. CAS does not contain detectable amounts of IL-2 as determined by its inability to support CTLL cell growth. Nor does it contain IL-1 or interferon. Examination of functional activity of lymphocytes stimulated for 3 days by CAS revealed that NK activity is augmented. This supernate does not appear to have any direct effect on B-cell function, although it induces suppression of polyclonal PWM stimulation of immunoglobulins. Thus, CAS appears to contain a new cytokine with immunomodulating potential.

Defective postbinding lysis underlies the impaired natural killer activity in factor VIII-treated, human T lymphotropic virus type III seropositive hemophiliacs

We investigated the diminished natural killer (NK) activity in human T lymphotropic virus type III (HTLV-III) seropositive hemophiliacs. Despite normal percentages of NK cells, lymphocytes from five hemophiliacs showed impaired NK activity against K-562 tumor cells in 4-h chromium release microcytotoxicity assays. For example, at an effector-to-target cell ratio of 10:1, cells from patients caused 21.7 +/- 2.5% lysis of tumor targets compared with 47.9 +/- 5.1% lysis by cells from controls (mean +/- SEM, P less than 0.005). Cells from patients were as cytotoxic in 18 h as were cells from controls in 4 h. Binding to tumor targets was not impaired since 11.0 +/- 1.5% of cells from patients and 11.1 +/- 1.3% of cells from controls bound to K-562 cells. Patients' binding cells, however, showed defective killing of attached tumor cells at all time points tested from 0 to 18 h. At 4 h, for example, patients' cells had lysed 10.9 +/- 2.1% of attached tumor cells compared with 26.3 +/- 3.3% lysis by controls' cells (P less than 0.005). The percentage of lymphocytes which were active NK cells (i.e., cells that bound and lysed a tumor cell) was always lower for patients than for controls (1.17 +/- 0.25% vs. 2.82 +/- 0.33%, P less than 0.005). Two methods for estimating recycling of effector cells against multiple target cells demonstrated that active NK cells from patients could recycle as well as those from controls (approximately 3-4 times in 4 h). Mixing experiments showed no evidence for cellular suppression of NK activity. The lytic function of NK cells from HTLV-III seropositive hemophiliacs is thus heterogeneous. This is characterized by a defect in post-binding lysis, with relative sparing of binding capability and recycling capacity.

Interleukin 1 activity in the acquired immunodeficiency syndrome

Interleukin 1 (IL-1) is a monocyte-derived mediator that participates in the regulation of various T-lymphocyte activities, among them IL-2 production. Since IL-2 deficiency is a central feature in the immunological profile of the acquired immunodeficiency syndrome (AIDS), the production of IL-1 from peripheral blood monocytes from male homosexuals with AIDS was investigated at the same time as the IL-1 responsiveness of monocyte-depleted mononuclear cells (MDC) from the same patients. The IL-1 was produced by lipopolysaccharide-stimulated monocytes and assayed by the capacity of monocyte supernatants to amplify the proliferation of phytohaemagglutinin-stimulated allogeneic MDC from healthy donors as well as murine thymocytes. The IL-1 responsiveness was measured by measuring the enhancing effect of an IL-1 standard on the proliferative response of patients' MDC. The IL-1 production was not reduced compared to the IL-1 production in a control group, but the IL-1 responsiveness of the patients' MDC was depressed. The results indicate that depressed IL-1 production is not one of the immunological disturbances in AIDS, but that the T-lymphocyte accessory properties of IL-1 are affected.

Defective T-cell differentiation in acquired immune deficiency syndrome (AIDS)

A decline in T-cell lymphocyte number is the central characteristic of acquired immune deficiency syndrome (AIDS). The reason for the loss of these cells is not well understood. We investigated the hypothesis that defects in T-cell differentiation contributed to T-cell loss using an in vitro colony assay that measures T-cell precursor (CFU-T) frequency. The results indicate a substantial generalized decrease in CFU-T in people with AIDS (P less than 0.01), most of whom have Kaposi's sarcoma, and an occasionally severe decrease in CFU-T in people with ARC. Some of the cells from low colony formers suppressed colony formation by control cells. In addition, plasma from people with AIDS was less supportive of colony growth than control plasma. Decreased Ia expression on adherent mononuclear cells did not correlate with colony formation. A defect in T-cell repopulation can help explain the loss of T cells associated with AIDS.

Effects of systemic in vivo interleukin-2 (IL-2) reconstitution in patients with acquired immune deficiency syndrome (AIDS) and AIDS-related complex (ARC) on phenotypes and functions of peripheral blood mononuclear cells (PBMC)

In the context of a clinical phase I/II therapy study with recombinant interleukin-2 (rIL-2), we monitored immunological alterations in four patients with acquired immune deficiency syndrome (AIDS) and three patients with AIDS-related complex (ARC). By determining the surface phenotypes and in vitro functions of peripheral blood mononuclear cells (PBMC) before, during, and after treatment with rIL-2, we observed transient changes in all important leukocyte subpopulations, a minor restoration of immune reactivity in vitro, and an improvement in skin reactivity in vivo. In particular, we found a transient increase in C3b receptor-mediated monocyte activation in ARC patients; no influence of therapy on the otherwise intact LPS-induced interleukin-1 production in vitro; in some patients a transient corrective influence on the high pretherapeutic immunoglobulin secretion of B cells and their nonresponsiveness to pokeweed mitogen; low T-cell responses to soluble antigens and alloantigens, which were partially restored during rIL-2 treatment in ARC patients and in one AIDS patient; defective NK activity in PBMC of two AIDS patients, which was found to be restored when measured at the end of rIL-2 therapy; and a rather constant phenotypic pattern of PBMC in each patient during therapy except for the decreasing proportion of OKT9-positive lymphocytes in AIDS patients, the increasing proportion of Leu8-Leu3a+ lymphocytes in all patients, and in particular, the transient significant decrease in the Leu7+/OKT3+ ratio, which pretherapeutically was very high in AIDS patients (0.78 +/- 0.21) and high in ARC patients (0.48 +/- 0.06) as compared to healthy controls (0.18 +/- 0.08).

Lack of natural killer cell activity in hairy cell leukemia patients and partial restoration with interleukin-2

Natural Killer (NK) cell activity was studied in ten hairy cell leukemia (HCL) patients by means of a 4-hour cytotoxicity assay using mononuclear cells isolated from either the spleen or peripheral blood. Identical assays were performed on individuals who were either normal or had nonmalignant hematologic disorders. HCL patients had a significant decrease in NK cell activity at all effector-to-target ratios compared with the control group. Effects of interleukin-2 (IL-2) on NK activity were studied in four patients. After a 3-day in vitro incubation with IL-2, there was a marked increase in NK activity of mononuclear cells obtained from each of these patients. On the basis of the results it can be hypothesized that susceptibility to infections, which are commonly encountered in HCL patients, may be due in part to a low level of NK activity. Based on the apparent augmentation of NK activity in vitro, it might be of interest to initiate a clinical trial with IL-2 in patients with HCL.

Defective gamma-interferon production in peripheral blood leukocytes of patients with acute tuberculosis

Production of interferon (IFN)-gamma by peripheral blood leukocytes (PBL) was examined in cultures of unseparated fresh whole blood exposed to phytohemagglutinin (PHA), concanavalin A (Con A), or pokeweed mitogen (PWM). The yield of IFN-gamma was measured by a newly developed immunoradiometric assay. Nine of 14 patients with acute pulmonary tuberculosis (TB) showed a depressed IFN-gamma response to Con A and/or PWM. Only four of these TB patients also showed a depressed IFN-gamma response to PHA. Stimulation of the patients' PBL cultures with PHA in the presence of exogenous interleukin 2 (IL 2) produced normal IFN-gamma yields in all but the most severely depressed patients. PBL cultures of TB patients with defective IFN-gamma production in response to mitogenic lectins also produced less IFN-gamma after stimulation with tuberculin PPD. Although some patients showed a moderate degree of lymphopenia, their OKT4/T8 lymphocyte ratios were mostly normal or close to normal, with the notable exception of one TB patient who has been diagnosed to have the acquired immune deficiency syndrome (AIDS).

Inhibition of interleukin 2 production and expression of the interleukin 2 receptor by plasma from acquired immune deficiency syndrome patients

Plasmas from acquired immune deficiency syndrome (AIDS) and AIDS-related complex (ARC) patients were screened for their ability to inhibit mitogen-induced proliferation of normal human lymphocytes. Plasmas from 67% of the individuals examined contained significant suppressive activity. Additional studies on the mechanism of action of the plasma inhibitor demonstrated that it functions as a nonlymphotoxic inhibitor of interleukin 2 production by stimulated human lymphocytes, and that this activity is accompanied by suppression of expression of the cell surface receptor for interleukin 2. A more detailed understanding of the action of this activity may aid in the design of therapy to minimize the contribution of this agent to the immune anergy observed in these patients.

Decreased natural and antibody-dependent cellular cytotoxic activities in intravenous drug abusers

Peripheral blood lymphocytes from 14 adult male patients admitted to the hospital with complications of intravenous drug abuse (IDA) were examined for natural killer (NK) and antibody-dependent cellular cytotoxic (ADCC) activities, lectin-dependent cellular cytotoxicity, and interferon (IFN)- and interleukin 2 (IL-2)-induced NK activity. Serum was also assayed for circulating interferon levels and soluble factor(s) capable of suppressing the cytotoxic potential of allogeneic lymphocytes from healthy donors. IDA patients demonstrated significantly decreased levels of NK and ADCC activities compared to age- and sex-matched healthy controls. The lectin, phytohemagglutinin, could significantly enhance the cytotoxicity of IDA lymphocytes; however, activity was not completely restored to normal levels. IDA sera demonstrated a significant inhibitory effect on the NK and ADCC activities of normal allogeneic lymphocytes, and these sera contained negligible levels of circulating IFN. Although the NK activity of IDA lymphocytes could not be restored completely to normal levels by either IFN-alpha or IL-2, the percentage enhancement of cytotoxicity was remarkably higher in IDA patients with significantly reduced NK activity than that observed using PBL from patients with near normal NK activity. The ability of IFN or IL-2 to enhance the decreased cytotoxicity of PBL from drug abusers suggests a novel therapeutic approach to the management of the complications of IDA.

Cloning and expression of human interleukin 2 in Streptomyces lividans using the Escherichia coli consensus promoter

Streptomyces lividans was transformed with a plasmid containing the structural gene that specifies human interleukin 2. The expression of interleukin 2 in this plasmid is controlled by both the consensus promoter and a consensus ribosome binding site characteristic of Escherichia coli. We have detected production of active human interleukin 2 in liquid cultures of the transformed Streptomyces by both, biological assay and immuno-blotting analysis.

Head and neck presentations of acquired immunodeficiency syndrome

Since December 1980, over 3000 cases of acquired immunodeficiency syndrome (AIDS) have been reported. The charts of 102 patients admitted to the New York University Medical Center with a diagnosis of AIDS were reviewed with particular emphasis on presenting signs, symptoms, and laboratory values. Symptoms tended to be nonspecific and most often resembled those of an upper respiratory infection. Over 71% of the patients presented with at least two of the following four signs: diffuse adenopathy, oral and facial lesions consistent with Kaposi's sarcoma, white oral lesions, and anergy. Laboratory findings included leukopenia, increased erythrocyte sedimentation rate, thrombocytopenia, and anemia. The in-hospital mortality rate was 26%. The current status of our knowledge concerning AIDS is reviewed and discussed. The frequency and types of presenting signs and symptoms in the head and neck are reported to alert the otolaryngologic community to this entity.

Diminished interleukin 2 production and receptor generation characterize the acquired immunodeficiency syndrome

The Acquired Immunodeficiency Syndrome (AIDS) is a disease found primarily in homosexual men, consisting of opportunistic infections and tumors, and is due to an acquired T-cell defect. In the present report, we studied various T-cell functions which might serve to distinguish homosexuals with a symptom complex including lymphadenopathy from those with AIDS. T lymphocytes from the lymphadenopathy and AIDS patients had markedly depressed proliferative responses in the autologous (auto) and allogeneic (allo) mixed lymphocyte reaction (MLR) compared to healthy homosexuals or heterosexual controls (P less than 0.001). Since proliferation in the MLR depends upon interleukin 2 (IL-2), a T-cell growth factor, we studied the production of and response to IL-2 in various groups of homosexuals and heterosexual controls. IL-2 production was markedly depressed in the lymphadenopathy and AIDS patients, 1.0 and 0.1 U/ml, respectively, compared to the healthy homosexual or heterosexual controls, both 5.0 U/ml (P less than 0.05 and P less than 0.01, respectively). Although the auto MLR of the lymphadenopathy patients rose to control values with the addition of exogenous IL-2, the auto MLR of the AIDS patients did not (P less than 0.01). This lack of responsiveness to IL-2 in the AIDS group was due to their inability to generate IL-2 receptors as shown by the absence of IL-2 absorption by activated cells and the absence of the Tac antigen (IL-2 receptor) on these same cells. The T4+ and T8+ T-cell subsets from the AIDS patients each demonstrated depressed IL-2 production and responsiveness following activation with autologous cells or mitogen, as well as the absence of Tac antigen. The diminished T-cell proliferation in the auto MLR in the lymphadenopathy group is associated with one defect, low IL-2 production, while the depressed proliferation in the AIDS group is associated with two defects, low IL-2 production and a lack of IL-2 receptor generation. These studies demonstrate that IL-2 receptor generation helps distinguish homosexuals with lymphadenopathy from those with AIDS, and that in addition to T-cell defects in the OKT4+ T-cell subset there are significant abnormalities in the OKT8+ T-cell subset in AIDS patients.

Suppressor T-cell activity in MRL/Mp-lpr/lpr mice: differential effects on primary and memory antibody responses of MRL/Mp-lpr/lpr and MRL/Mp-+/+ spleen cells to thymus dependent and thymus independent antigens in vitro

We have previously shown that suppressor-T-cell (TS) activity in the spleens of autoimmune MRL/Mp-lpr/lpr (MRL/l) mice is increased after 2 months of age. The TS suppress the in vitro primary IgM response to the thymus-dependent (TD) antigen sheep erythrocytes (SRBC) of B and T cells from young congenic MRL/Mp-+/+ (MRL/n) mice which lack the lymphoproliferation (lpr) gene. The TS are nylon wool nonadherent, Thy 1.2 positive, and radiation sensitive. The studies presented here were done to further characterize the TS and to attempt to determine the mechanism of action of these cells. We found that increased TS activity was also present in the proliferating lymph nodes of old MRL/l mice but not in lymph nodes of young MRL/l or MRL/n mice. The splenic TS equally suppressed the primary IgM SRBC response of both young MRL/l and MRL/n B and T cells, indicating that MRL/l SRBC-specific B and T cells are not resistant to suppression. The IgM response of MRL/n B and T cells to the T-independent (TI) antigen trinitrophenyl conjugated to Brucella abortus (TNP-BA) was not suppressed by the TS, although the IgM response to TNP was suppressed when TNP was coupled to the TD carrier SRBC. The results of kinetics studies of TS expression showed that when the TS were added on Day 0 of culture the SRBC response was suppressed as early as Day 2 of culture; however, when the TS were added on Days 1, 2, or 3 of culture, the suppression was reduced. The TS suppressed the in vitro memory IgG response of spleen cells from MRL/n mice which had been primed with SRBC; the memory IgG responses of spleen cells from MRL/l mice were variably suppressed. Taken together, these results suggest that the TS suppress TH function in early events of antibody production and that some activated B or T cells may be resistant to the effects of the TS. Increased TS activity was not present in the spleens of aged New Zealand Black X NZ White (NZB/W) F1 mice. Possible reasons for the presence of increased TS activity in MRL/l mice and its relation to autoimmune disease is discussed.

Production of and in vitro response to interleukin 2 in the acquired immunodeficiency syndrome

To test the hypothesis that deficient interleukin 2 (IL-2) secretion may underlie the impaired capacity of T cells from patients with Acquired Immunodeficiency Syndrome (AIDS) and the AIDS-related complex (ARC) to generate the macrophage-activating lymphokine, gamma interferon (IFN-gamma), we used five specific microbial antigens to examine IL-2 production. Mononuclear cells from only one of 32 (3%) AIDS patients secreted normal levels of IL-2, and 21 (66%) failed to produce any detectable IL-2. For 36 ARC patients, IL-2 generation was normal in nine (25%) and absent in 11 (31%). Given these results, recombinant (r) IL-2 was tested for its capacity to stimulate or enhance IFN-gamma production. rIL-2 (10 U/ml) alone stimulated cells from controls, ARC, and AIDS patients to secrete 93 +/- 25, 99 +/- 33, and 7 +/- 3 U/ml of IFN-gamma, respectively. rIL 2 (10 U/ml) plus antigen induced no change in mean IFN-gamma levels for controls, a 4.4-fold increase for 17 AIDS patients (16 +/- 16 vs. 71 +/- 21 U/ml), and a 7.2-fold increase (18 +/- 5 vs. 130 +/- 27 U/ml) for 19 ARC patients with abnormal IFN-gamma generation to antigen alone. Individual responses indicated that six of the 17 (35%) AIDS patients with opportunistic infections and 12 of the 19 (63%) with ARC were apparent responders to 10-100 U/ml of rIL-2. These results (a) document profound impairment in antigen-induced IL-2 secretion by AIDS and ARC T cells, (b) indicate that, in vitro, mononuclear cells from certain patients can respond to rIL-2 with enhanced IFN-gamma production, and thus (c) suggest that in selected patients rIL-2 might have a potentially beneficial therapeutic (AIDS) or prophylactic (ARC) effect against opportunistic infections.

Cytotoxic capabilities of lymphocytes from patients with the acquired immunodeficiency syndrome

Lymphocytes from 16 AIDS patients were tested in the cell-mediated lympholysis assay (CML). The ability to produce alloreactive cytotoxic lymphocytes in vitro was found to be substantially reduced when compared with concomitantly investigated normal controls. Addition of interleukin 2 (IL-2) to the inducer cultures increased the cytotoxic activity, but not to normal levels. The CML response did not correlate with the relative or absolute number of Leu 3+ cells or the proliferation in effector suspensions. The ability to produce cytotoxic cells in CML, and the degree of potentiation by IL-2, was positively correlated with the absolute number of Leu 2+ cells in peripheral blood of the patients, which was below normal in 56% of the patients. It is suggested that the low CML in AIDS patients is primarily caused by defective T-cell help. In addition patients with decreased absolute numbers of Leu 2+ cells may have a reduced number of CTL precursors. The natural killer (NK) activity of AIDS lymphocytes was reduced, but could be improved by incubation with IL-2 in vitro. The mononuclear cells from the patients showed a decreased ability to respond and to stimulate in the mixed lymphocyte culture. In one of the AIDS patients, the CML was found to induce autoreactivity in vitro.

Functional comparison of recombinant interleukin 2 (IL-2) with IL-2-containing preparations derived from cultured cells

Due to its purity and potential availability in large amounts, human recombinant interleukin 2 (IL-2) expressed in Escherichia coli is an important source of IL-2 for experimentation and possible therapy. To date, very few comparisons between the activity of recombinant IL-2 and conventional cell-derived preparations of IL-2 have been made. This is particularly important since the use of recombinant IL-2 may have some specific limitations. For example, recombinant IL-2 is not post-translationally modified as are cell-derived preparations. Lack of modifications such as glycosylation of threonine 3 may alter efficacy or stability. Comparative studies are necessary to demonstrate the efficacy, species specificity, and stability of recombinant IL-2. By comparing IL-2 activity of recombinant IL-2 to that of cell-derived IL-2, we have demonstrated that each of the preparations are equally active in several murine and human IL-2 proliferation assays and that IL-2 is the active moiety in these assays. In contrast to previous reports, we also show that recombinant IL-2 is sufficient to establish and maintain long-term cell lines. Additionally, by using "synthetic" recombinant IL-2 of defined protein sequence, we have demonstrated that this amino acid-defined structure is indeed responsible for the functions attributed to IL-2.

Prospective study of cytotoxic T lymphocyte responses to influenza and antibodies to human T lymphotropic virus-III in homosexual men. Selective loss of an influenza-specific, human leukocyte antigen-restricted cytotoxic T lymphocyte response in human T lymphotropic virus-III positive individuals with symptoms of acquired immunodeficiency syndrome and in a patient with acquired immunodeficiency syndrome

Peripheral blood leukocytes (PBL) from 18 homosexual men who did not have acquired immunodeficiency syndrome (AIDS) and from 9 heterosexual men were repetitively tested for their ability to generate HLA self-restricted cytotoxic T lymphocyte responses to influenza virus (flu-self) over a 2-yr period. The sera of the same donors were tested for antibodies to human T lymphotropic virus-III (HTLV-III). Six of the homosexual and none of the heterosexual donors consistently generated weak cytotoxic T lymphocyte responses to flu-self. Seven of the homosexual and none of the heterosexual donors were seropositive for antibodies to HTLV-III. No obvious correlation was detected between weak flu-self cytotoxic T lymphocyte responses and antibodies to HTLV-III. However, one homosexual donor generated no detectable cytotoxic T lymphocyte activity to flu-self, although he was a strong responder to HLA-alloantigens. This donor had an OKT4:OKT8 ratio of 0.4 and was seropositive for HTLV-III antigens; HTLV-III virus was identified in his PBL; and he developed AIDS during the course of this study. A second donor with lymphadenopathy and who was seropositive for HTLV-III antigens exhibited marginal cytotoxic T lymphocyte activity to flu-self which he subsequently lost. PBL from two patients, one with Kaposi's sarcoma and one with generalized lymphadenopathy, were also tested for cytotoxic T lymphocyte responses to flu-self and to alloantigens. Both donors failed to generate cytotoxic T lymphocyte to flu-self, but generated strong cytotoxic T lymphocyte responses to alloantigens. The selective loss of an HLA-restricted cytotoxic T lymphocyte response without loss of HLA alloantigenic cytotoxic T lymphocyte activity may be an important functional immunologic characteristic in the development of AIDS.

Effects of cyclosporine in experimental cryptococcal meningitis

We studied the effects of cyclosporine on experimental cryptococcal meningitis. Like cortisone, cyclosporine depressed the highly effective defense mechanisms of normal rabbits against inoculated Cryptococcus neoformans, causing them to develop progressive, fatal cryptococcal meningitis. Unlike cortisone, which causes a striking reduction in leukocytes in cerebrospinal fluid, cyclosporine depressed mononuclear cell function rather than numbers. Interleukin 2, a primary target for the immunodepressive action of cyclosporine, appears to be of central importance in central nervous system defenses against cryptococci. The findings suggest that humans receiving cyclosporine are likely to suffer increased incidence of cryptococcal infection.

[Growth factors. A new dimension in understanding oncogenesis]

The current understanding in biology and function of 4 growth factors is reviewed. PDGF suggests functions for proto-oncogens in normal cells, which may interact in tightly linked hierachies to induce malignant growth. PDGF-requirement of normal fibroblast cell-lines is lost when the cells are infected with tumor viruses. TGF is able to stimulate growth of normally anchorage dependent cells in an anchorage independent manner in soft agar. This ability is thought to be the best in-vitro correlate of neoplastic transformation. The peptide hormones bombesin/gastrin releasing factor and EGF can act as autocrine growth factors in various lung cancer cell-lines and stimulate clonal tumor cell growth in-vitro. The potential clinical application of these types of growth factors may enable the in-vitro growth from any lung cancer patient and allow individual drug testing. TCGF produced by T-cells to activate T-cells, is central to immune stimulation and immune response. Models for potential indirect anticancer effects either by in-vivo administration or by in-vivo incubation plus passive transfer of T-cells are presented to be initiated in future clinical trials.

Cytotoxic activity of peripheral blood lymphocytes grown with interleukin 2 against autologous cultured tumor cells in patients with renal cell carcinoma: preliminary report

To examine the use of interleukin 2 as a therapeutic agent for human renal cell carcinoma the peripheral blood lymphocytes derived from patients with renal cell carcinoma were grown in interleukin 2 and tested in a 4-hour 51chromium release cytotoxicity assay against autologous cultured tumor cells. Peripheral blood lymphocytes, which were cultured separately in medium alone, mitomycin C-treated tumor cells, 20 per cent interleukin 2 and tumor cells plus interleukin 2, were used as effector cells. In all patients neither peripheral blood lymphocytes in medium alone nor in mitomycin C-treated tumor cells could lyse their own tumor cells. However, in 5 of 7 patients peripheral blood lymphocytes grown in interleukin 2 regardless of the presence of mitomycin C-treated tumor cells were capable of causing 5.7, 9.4, 12.7, 36.1 and 52.5 per cent lysis at effector/target cell ratios of 25, 50, 50, 50 and 25, respectively. However, more significant cytotoxicity was not obtained by peripheral blood lymphocytes cultured with tumor cells and interleukin 2. These results suggest that interleukin 2 might become a useful agent for patients with renal cell carcinoma.

Immunological and virological investigation in patients with lymphoadenopathy syndrome and in a population at risk for acquired immunodeficiency syndrome (AIDS), with particular focus on the detection of antibodies to human T-lymphotropic retroviruses (HTLV III)

Thirteen patients affected with unexplained lymphoadenopathy, fever, weight loss, and diarrhea (lymphoadenopathy syndrome; LAS) were evaluated for the possible appearance of acquired immunodeficiency syndrome (AIDS) and for immunological and virological characterization. The patients belonged to categories of individuals at risk for AIDS and were homosexual and/or drug abusers or hemophiliacs. Lymph node biopsy showed the histological picture of a follicular hyperplasia. The study of cell-mediated immunity (CMI), humoral immune response, and natural killer (NK) activity demonstrated a significant decrease in T cells with the helper/inducer phenotype (OKT4+ cells) and a relatively increased number of lymphocytes with the suppressor/cytotoxic phenotype (OKT8+ cells). NK activity was significantly lower than in normal controls. The in vitro response to polyclonal activators (phytohemagglutinin; PHA) and the cutaneous responsiveness to recall skin tests were impaired, whereas immunoglobulin production was increased, mainly in the IgG fraction. Virological studies showed high serum antibody titers to cytomegalovirus (CMV) but a lack of specific CMI as assayed by the leukocyte migration inhibition test (LMIT). CMV was also isolated from the urine specimen of one patient. The antibody pattern to Epstein-Barr virus (EBV) showed the uncommon contemporary presence of both Epstein-Barr nuclear antigen (EBNA) and early antigen (EA) antibodies. Antibodies to human T-lymphotropic retroviruses (HTLV III) were positive in 10 patients and the virus was isolated in 3 of them. In some patients the presence of serum antibodies to HTLV III was not associated with an impairment of the immune function. A group of individuals at risk for AIDS without LAS was also evaluated for the presence of HTLV III antibodies; the percentage of positive sera was 11.4.(ABSTRACT TRUNCATED AT 250 WORDS)

Sera from patients with the acquired immunodeficiency syndrome inhibit production of interleukin-2 by normal lymphocytes

We studied the effects of sera from patients with the acquired immunodeficiency syndrome (AIDS) on interleukin-2 (IL-2) production to help elucidate the mechanism of immunodeficiency. Compared with sera from healthy controls, sera from AIDS patients suppressed phytohemagglutinin (PHA)-induced IL-2 production by normal blood mononuclear cells. Sera from homosexual contacts of AIDS patients and from adults with acute cytomegalovirus infection generally lacked this suppressive activity. The effect of the AIDS sera could not be attributed to absence of a stimulatory or nutritive factor, to inactivation of IL-2, to inhibition of the IL-2 assay, nor to increased turnover of IL-2. The suppressive effect of the sera was not mediated by radiosensitive or T8 antigen-bearing suppressor cells or by increased prostaglandin production or decreased interleukin-1 production. The sera acted directly on the groups of cells that produce IL-2, T cells and large granular lymphocytes; suppression occurred at an early, probably pretranslational, stage. When cells were incubated with AIDS sera and then washed, the suppressive effect persisted. The sera did not cause direct or complement-mediated cytotoxic effects on normal mononuclear cells nor did they suppress PHA-induced interferon production, nor proliferation of T lymphoblasts or lymphocyte lines. The suppressive effect was not mediated by interferon, cortisol, immunoglobulin G or M, or immune complexes. The activity was stable at pH 3, pH 10, and 60 degrees C; inactivated at 100 degrees C; and not ether extractable. Because IL-2 plays a central role in the development of many immune responses, the serum factor(s) that inhibits IL-2 production could contribute significantly to the immunodeficiency of AIDS.

Immunologically oriented concept of the genesis of acquired immunodeficiency syndrome

An immunologically oriented concept of the genesis of acquired immunodeficiency syndrome is presented in which the central event is the lack of cytotoxic T8 cells. An interlocking system wherein the T4 (helper) cells do not synthesize interleukin-2 to generate the cytotoxic cells due to the lack of functional thymosin as well as the lack of interleukin-1 from the macrophages is postulated. The transmissible agent which sets the cascade of immunologic imbalance into play replicates only in the thymic epithelium and subverts thymosin synthesis. The T8 cells in the syndrome are exclusively H2 positive and functionally suppressor. The macrophage which phagocytizes the effete thymic epithelium hematogenously spreads the transmissible agent to others. Kaposi's sarcoma is considered to be an integral component of the immunologic disarray in that angiogenesis is proposed to require two essential events - endothelial cell proliferation and movement of those cells. Under normal circumstances although the activated macrophage elaborates a monokine that has endothelial cell proliferative inducing capacity the cells are held in situ by a lymphokine that prevents movement. The lymphokine is considered to be IL-2. Eight predictions of the model which are experimentally testable are presented.

Impaired natural killer cell activity in Bloom's syndrome could be restored by human recombinant IL-2 in vitro

Natural killer (NK) activity against K562 tumor cells was evaluated in peripheral blood nonadherent mononuclear cells (PBMNC) obtained from four patients with Bloom's syndrome. NK activity of PBMNC from all patients was found to be depressed to less than half of age-matched control values. However, all patients showed the normal percentages of large granular lymphocytes and of cells expressing the NK-cell-associated determinants (OKM1, Leu-7, and Leu-11). Although recombinant interferon-beta or -gamma augmented NK activity of patients' PBMNC in a manner similar to their effects on NK activity of normal individuals, impaired NK activity of PBMNC from Bloom's patients could be restored to normal ranges only by recombinant interleukin 2 (IL-2). These results suggested that IL-2 and interferons might participate in boosting NK activity of Bloom's syndrome in different ways.

Partial restoration of impaired interleukin-2 production and Tac antigen (putative interleukin-2 receptor) expression in patients with acquired immune deficiency syndrome by isoprinosine treatment in vitro

The in vitro effects of isoprinosine (ISO) on interleukin-2 (IL-2) production, the expression of Tac antigen (IL-2 receptor) on lymphocytes, and the ability of Leu 3(+) cells to absorb interleukin-1 (IL-1) were investigated in 10 patients with acquired immune deficiency syndrome (AIDS). In 9 of the 10 patients, production of IL-2 from mononuclear cells and Leu 3(+) cells was depressed; expression of Tac antigen on mononuclear cells and Leu 2(+) cells was found to be depressed in 9 of 10 patients. The ability of the Leu 3(+) lymphocytes to absorb IL-1 was depressed in all (four of four) patients studied. After ISO treatment, IL-2 production, Tac antigen expression and IL-1 absorption were restored to normal or near normal levels in most of the patients. These results suggest that ISO has an immunostimulating capacity in AIDS patients and that the potential of ISO in immune response restoration in AIDS patients deserves critical consideration.

Comparison of the biological properties of purified natural and recombinant human interleukin-2

We compared the biological properties of the purified recombinant human IL-2 derived from E. coli with those of purified natural IL-2. Both had almost the same specific in vitro activities on a weight basis to support long-term proliferation of IL-2 dependent human peripheral blood lymphocytes, a mouse killer T cell line, and a mouse natural killer cell line; induce killer cells in normal mouse spleen cells; and induce antibody forming cells in nude mouse spleen cells. No differences in these biological activities were found between two forms of natural IL-2 that were separable by reverse phase high performance liquid chromatography.

Immunoregulatory circuits in the acquired immune deficiency syndrome and related complex. Production of and response to interleukins 1 and 2, NK function and its enhancement by interleukin-2 and kinetics of the autologous mixed lymphocyte reaction

The production of the T cell lymphokine interleukin-2 (IL-2) was found to impaired in all of seven male patients with AIDS or homosexuals with persistent generalized lymphadenopathy (AIDS related complex, AIDS-RC) whom we studied. Conversely the T cell response to IL-2 was found unimpaired as was the production of the monocyte factor interleukin-1 (IL-1). The response of T cells to IL-1 was found markedly decreased in two of the four patients with AIDS and in two of the three patients with AIDS-RC. Five of six patients had flat curves in autologous mixed lymphocyte cultures with no significant proliferative response throughout 7 days. The exception was a Haitian heterosexual patient with AIDS. Natural killer cell function was decreased in three of four patients with AIDS and two of three patients with AIDS-RC but it augmented normally in the presence of IL-2 in four, including the two who had it normal basally. Responses to pokeweed mitogen were within normal limits in all seven patients despite decreased responses to concanavalin A and phytohaemagglutinin. These findings help pinpoint the defect in AIDS to the T4+ cell, and perhaps even to one of its subpopulations, and suggest a role for IL-2 in the treatment of AIDS.

Interleukin-2 restores the depressed allogeneic cell-mediated lympholysis and natural killer cell activity in patients with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is characterized by a variety of profound T-cell abnormalities among which are decreased cytotoxic capacity measured by allogeneic cell-mediated lympholysis (CML), natural killer cell (NK) activity, and decreased lymphokine production. In a group of 13 patients with active SLE, allogeneic CML, tested by a 4-hr 51Cr-release assay, was 18.2 +/- 2.7% while in the group of normal individuals CML was 41.2 +/- 2.7%. If optimal doses of affinity-purified interleukin-2 (IL-2) were present during the mixed lymphocyte culture, the CML of SLE patients was increased to normal levels (40.4 +/- 4.0%). In contrast, interferon-alpha (IFN-alpha) increased (but not significantly) the levels of CML. Mixed lymphocyte reaction, tested by tritiated thymidine incorporation, was also decreased in the group of patients (14,820 +/- 815 cpm vs 28,972 +/- 5880 cpm in normals) and it was increased to normal levels if IL-2, but not IFN-alpha was added to the cultures. NK activity was decreased in the group of patients tested by 51Cr-release assay, harvested at 6 and 18 hr. IL-2 increased the NK activity up to normal levels, while IFN-alpha was only partially efficacious. These results demonstrate that IL-2, but not IFN-alpha, can potentiate or even fully restore the deficient cytotoxic effector function of peripheral mononuclear cells in patients with SLE.

Acquired immunodeficiency syndrome and the emergency physician

Aids is a new public health disaster that is unlikely to be resolved quickly. It is manifested by a profound immune deficiency accompanied by the development of KS, PCP, and/or other opportunistic infections. A retrovirus, HTLV-III, is the probable cause of the immunosuppression, and it is transmitted in a manner similar to hepatitis B virus. Groups at highest risk include homosexual men, intravenous drug abusers, Haitians, and hemophiliacs. Therapy is largely experimental, and mortality is high. The emergency physician must be familiar with the signs, symptoms, and early management of AIDS. He should be able to offer guidance on disease prevention to both health care workers and members of high-risk groups. Allocation of major financial resources and intensive investigation are necessary to abort this cruel epidemic that affects primarily younger persons. Such investigation will undoubtedly produce new advances in virology, oncology, and immunology that will benefit medicine and society as a whole.

Interleukin 2 therapy in infectious diseases: rationale and prospects

Clinical trials using interleukin 2 as a therapeutic immunomodulating agent in patients with acquired immunodeficiency syndrome have recently begun. In this article we present data from studies which indicate the ability of interleukin 2 in vitro to augment clinically important cytotoxic immune responses in lymphocytes from these patients. These studies provide both a rationale for the current trials and a model for evaluating the potential for use of interleukin 2 in other infectious diseases. We outline the types of infectious diseases in which interleukin 2 may prove to be useful and the therapeutic strategies in which it may play a role.

Effect of cyclosporin and interleukin-2 on the restoration of in vitro immune responses to cytomegalovirus

Previous studies have shown that cyclosporin (CSA) inhibits lymphoproliferation to cytomegalovirus (CMV)-infected, glutaraldehyde-fixed, and irradiated fibroblasts (CMVFFx) in vitro. Generation of cytotoxic cell activity is impaired in cultures with CSA, but the induction of suppressor cells is not. In the present studies we tested the ability of interleukin-2 (IL-2) and supernatants of lymphocytes stimulated by CMVFFx with or without CSA (1 microgram/ml) to restore functional activities of lymphocytes from primary cultures treated or not treated with CSA. IL-2 significantly enhanced lymphoproliferation, cell-mediated cytotoxicity to CMV-infected fibroblasts (CMVF), natural killer cell activity, and the activity of cells capable of suppressing the response of fresh autologous cells to CMVFFx of cells derived from control and CSA-treated primary cultures. IL-2 was found in day-2 supernatants of control cultures but not CSA-treated cultures. Day-2 control supernatants were capable of significantly enhancing proliferation and suppressor cell activity but were less efficient at restoring cytotoxic cell function. Day-2 supernatants from CSA-treated cultures were not able to enhance lymphoproliferation or cytotoxic cell function but did induce significant levels of suppressor cell activity. The results indicate the presence of different functional mediators in the culture supernatants. The ability of IL-2 to restore lymphocyte effector functions against a clinically important virus may have important therapeutic implications in the treatment of this viral infection in immunodeficiency diseases and in the restoration of immune competence after transplantation.

Decreased population of Leu-7+ natural killer cells in lymph nodes of homosexual men with AIDS-related persistent lymphadenopathy

Natural killer (NK) cells were studied in the lymph nodes of homosexual men with the persistent lymphadenopathy syndrome (PLS) and other signs of the disease complex related to the acquired immune deficiency syndrome (AIDS). The NK cells were identified by their Leu-7+ phenotype and enumerated in frozen sections of lymph nodes in conjunction with the quantification of T-lymphocyte subsets. Lymph nodes from patients with AIDS-related PLS contained 91% and 81% fewer NK cells than normal lymph nodes and lymph nodes from patients with non-AIDS-related hyperplastic lymphadenopathy respectively. This decrease in NK cells in PLS is consistent with the immune dysregulation leading to persistent infection and neoplasia in AIDS.

Preliminary clinical observations with recombinant interleukin-2 in patients with AIDS or LAS

The toxicity of recombinant Interleukin-2 (IL-2) was studied in patients with acquired immunodeficiency syndrome (AIDS) or persistent lymphadenopathy syndrome (LAS). Increasing doses of the drug from 10(3) Units/m2 to 10(6) U/m2 were given as an intravenous bolus injection. At the high-dose levels some minor effects, such as fever up to 39.5 degrees C, chills, malaise or vomiting, were observed. The administration of 10(6) U/m2 as a 4-hour infusion showed identical results. No particular alterations of laboratory parameters were found. At the high-dose level the serum concentration of neopterin, which is released from macrophages after interferon gamma stimulation, was significantly (p less than 0.001) elevated above pretreatment levels. The clinical observation of daily infusions of 10(6)/m2 for 14 days revealed the same side effects. All patients developed lymphocytosis and eosinophilia. Two patients had suffered from severe diarrhoea for several weeks presumably due to cryptosporidiosis. In both cases diarrhoea ceased under the treatment with IL-2 and did not occur in the following two months.