Inability of memory T cells to induce graft-versus-host disease is a result of an abortive alloresponse

Several groups, including our own, have independently demonstrated that effector memory T cells from non-alloantigen-primed donors do not cause graft-versus-host disease (GVHD). In the current study, we further investigated whether this approach could be extended to all memory T cells, and we studied the underlying mechanisms. Neither total memory T cells nor purified central memory T cells were able to induce GVHD. Memory T cells were at least 3-log less potent than bulk T cells in mediating GVHD. As expected, memory T cells failed to elicit cytotoxicity and proliferated poorly against alloantigens in standard 5-day mixed-lymphocyte cultures. However, the proliferative responses of memory T cells were more comparable with those of bulk and naive T cells when the culture time was shortened. Moreover, the frequencies of IL-2-secreting cells measured by 42-hour enzyme-linked immunosorbent spot (ELISPOT) assay were similar among naive, memory, and bulk T cells. These data indicated that memory T cells are able to respond to alloantigens initially but fail to develop to full potential. The abortive immune response, which was mediated by non-alloantigen-specific memory T cells in response to alloantigens, may explain why memory T cells from unprimed and non-alloantigen-primed donors could not induce GVHD.

Prophylaxis and treatment of acute graft-versus-host disease

Acute graft-versus-host disease (GVHD) remains a major obstacle to successful allogeneic hematopoietic stem cell transplantation (HSCT). The ability to prevent GVHD--the application of successful prophylaxis--is crucial as treatment when prophylaxis fails or remains suboptimal. A calcineurin inhibitor in combination with methotrexate is still the mainstream regimen for prophylaxis of GVHD. Despite a steady increase in the repertoire of available drugs, corticosteroids remain the first-line therapy for patients who fail prevention and develop GVHD. Pan T-cell depletion studies suggest that success in prophylaxis and treatment of GVHD will depend on whether GVHD can be prevented without losing anti-malignancy and anti-infectious effects. Better understanding of the allogeneic response that is responsible for GVHD will facilitate the development of such an approach.

Selective elimination of alloreactivity from immunotherapeutic T cells by photodynamic cell purging and memory T-cell sorting

Allogeneic stem cell transplantation (alloSCT), especially in the mismatched setting, carries a high risk of life-threatening GvHD because of activation of donor T cells by Ag present on host cells. Removal of mature donor T cells can prevent GvHD but leads to delayed immune reconstitution, and an increased incidence of opportunistic infections and disease relapse. These findings demonstrate the vital role of donor T cells in providing graft-versus-tumor (GvT) and anti-pathogen effects as well as facilitating immune reconstitution. It has been well documented that GvHD can be separated from GvT effects, making it possible potentially to eliminate GvHD while preserving the immunotherapeutic benefits of donor T cells. Over the past decade, major attempts have been made to reduce GvHD incidence without loss of GvT effect, especially in the haplo-identical setting. Novel techniques to deplete host-reactive donor T cells selectively have been explored. This review focuses on the use of the photodynamic cell purging (PDP) process and of sorting memory T cells for the selective elimination of alloreactivity. Minimizing the threat of GvHD while maximizing the beneficial GvT effect would broaden the scope and effectiveness of alloSCT.

The critical role of hematopoietic cells in lipopolysaccharide-induced airway inflammation

Rapid and selective recruitment of neutrophils into the airspace in response to LPS facilitates the clearance of bacterial pathogens. However, neutrophil infiltration can also participate in the development and progression of environmental airway disease. Previous data have revealed that Toll-like receptor 4 (tlr4) is required for neutrophil recruitment to the lung after either inhaled or systemically administrated LPS from Escherichia coli. Although many cell types express tlr4, endothelial cell expression of tlr4 is specifically required to sequester neutrophils in the lung in response to systemic endotoxin. To identify the cell types requiring trl4 expression for neutrophil recruitment after inhaled LPS, we generated chimeric mice separately expressing tlr4 on either hematopoietic cells or on structural lung cells. Neutrophil recruitment into the airspace was completely restored in tlr4-deficient mice receiving wild-type bone marrow. By contrast, wild-type animals receiving tlr4-deficient marrow had dramatically reduced neutrophil recruitment. Moreover, adoptive transfer of wild-type alveolar macrophages also restored the ability of tlr4-deficient recipient mice to recruit neutrophils to the lung. These data demonstrate the critical role of hematopoietic cells and alveolar macrophages in initiating LPS-induced neutrophil recruitment from the vascular space to the airspace.

A survey of microbial contamination of food contact surfaces at broiler slaughter plants in Taiwan

Microbial contamination levels at broiler slaughter plants were investigated at three major slaughter plants in Taiwan during the summer and winter. The microbial contamination levels in chicken carcasses and on food contact surfaces were examined using the swab method. The results indicated that the bacterial counts were affected by the slaughter processing plant, processes, and season (P < 0.05). The bacterial counts on food contact surfaces of the equipment before operation were not significantly lower than those after processing. Regardless of the bacterial type, bacterial counts of chicken carcasses generally decreased from the scalding step to the washing step before evisceration and then increased. The cleaning procedures for food contact surfaces should be evaluated, and special attention should be given to utensils used during processing, such as gloves, baskets, and hand tools.

Hematopoietic stem cell dose correlates with the speed of immune reconstitution after stem cell transplantation

In the current study, we tested whether higher numbers of hematopoietic stem cells correlate with the speed of immune reconstitution in a congenic transplantation model (C57BL/Ka, CD45.1, Thy1.1→C57BL/6, CD45.2, Thy1.2) using purified hematopoietic stem cells (c-Kit+Thy1.1lowLin-/lowSca-1+). There were 3 different doses of stem cells used (400, 1000, and 5000). Phenotypic analyses in peripheral blood and spleen demonstrated that higher numbers of infused stem cells are associated with more rapid regeneration of T cells (CD4+, CD8+, naive CD4+, naive CD8+) and B cells at early time points. The numbers of T and B cells eventually became equivalent between different dose groups at late time points. Production of interleukin-2 and inter-feron-γ per T cell was similar regardless of stem cell dose even when tested at the time when there were significant differences in peripheral T-cell counts. The improved immune recovery was attributed to a more rapid regeneration of donor-type immune cells. Higher numbers of total thymocytes and signal joint T-cell receptor excision circles were observed in the higher dose stem cell recipients, suggesting that accelerated regeneration of T cells was due to enhanced thymopoiesis. (Blood. 2004;103:4344-4352)

Growth hormone accelerates immune recovery following allogeneic T-cell-depleted bone marrow transplantation in mice

OBJECTIVE

To test in a murine model whether recombinant human growth hormone can promote immune recovery after allogeneic T-cell-depleted bone marrow transplantation.

MATERIALS AND METHODS

Lethally irradiated (8.5 Gy) BALB/c mice (H2(d)) were transplanted with 5 x 10(6) T cell-depleted bone marrow cells from C57BL/6 mice (H2(b)). Recipient mice were injected intraperitoneally with recombinant human growth hormone (20 microg/dose/day) or saline for the first 4 weeks after transplantation. These animals were followed for phenotypic and functional immune recovery.

RESULTS

Administration of human recombinant growth hormone improved the CD4(+) T-cell counts in peripheral blood on day +14 (44+/-14 vs 33+/-7/microL blood, p<0.05) and day +21 (281+/-109 vs 187+/-76/microL blood, p<0.01) compared with the saline control. These differences were no longer significant by day +28 despite continued growth hormone administration. Similar effects were also observed on CD8(+) T cells and B220(+) B cells. The improvements in peripheral T-cell counts were at least partially as a result of enhanced thymopoiesis because there was an increase in total thymocytes after treatment with growth hormone. T-cell-depleted bone marrow recipients treated with growth hormone rejected the third-party grafts faster than those treated with saline control (median survival time: 20 days vs 26 days, p<0.05).

CONCLUSIONS

These data demonstrated that recombinant human growth hormone can accelerate phenotypic and functional immune reconstitution following allogeneic T-cell-depleted bone marrow transplantation in mice.

Transfer of allogeneic CD62L- memory T cells without graft-versus-host disease

The major challenge in allogeneic hematopoietic cell transplantation is how to transfer allogeneic T-cell immunity without causing graft-versus-host disease (GVHD). Here we report a novel strategy to selectively prevent GVHD by depleting CD62L(+) T cells (naive and a subset of memory T cells). In unprimed mice, CD62L(-) T cells (a subset of memory T cells) failed to proliferate in response to alloantigens (which the mice have never previously encountered) and were unable to induce GVHD in allogeneic hosts. CD62L(-) T cells contributed to T-cell reconstitution by peripheral expansion as well as by promoting T-cell regeneration from bone marrow stem/progenitor cells. CD62L(-) T cells from the animals previously primed with a tumor cell line (BCL1) were able to inhibit the tumor growth in vivo but were unable to induce GVHD in the third-party recipients. This novel technology may allow transfer of allogeneic recall antitumor and antimicrobial immunity without causing GVHD.

Nonmyeloablative regimen preserves "niches" allowing for peripheral expansion of donor T-cells

T-cell recovery following myeloablative preparatory regimens and cord blood transplantation in adult patients gen erally occurs between 1 and 3 years following allogeneic bone marrow transplantation. T-cell reconstitution may involve thymic education of donor-derived precursors or peripheral expansion of mature T-cells transferred in the graft. We measured quantitative and qualitative immunologic reconstitution, T-cell receptor spectratyping, and T-cell receptor excision circle (TREC) levels in adult recipients of umbilical cord blood transplants following a novel nonmyeloablative regimen. These results were compared to previously published results of similar patients receiving a myeloablative regimen and cord blood stem cells. With small numbers of patients treated so far, T-cells (CD3+) reached normal levels in adults 6 to 12 months following nonmyeloablative transplantation compared with 24 months in adults receiving a myeloablative regimen. At 12 months after transplantation, the numbers of phenotypically naive (CD45RA) T-cells were higher in those receiving the nonmyeloablative regimen. The T-cell repertoire in cord blood recipients treated with a nonmyeloablative regimen was markedly more diverse and robust compared with the repertoire in those receiving the myeloablative regimen at similar time points. TRECs (which are generated within the thymus and identify new thymic emigrants and those that have not divided) were detected 12 months after transplantation in the nonmyeloablative recipients, whereas TRECs were not detected in adults until 18 to 24 months in those receiving myeloablative regimens. Thus, in adults receiving a nonmyeloablative preparatory regimen, the quantitative and qualitative recovery of T-cells occurs through rapid peripheral expansion. The ability of patients receiving a nonmyeloablative regimen to recover within a few months suggests that the peripheral niches in which T-cells can proliferate are preserved in these patients compared to those receiving ablative regimens. Moreover, the presence of TREC-positive cells within 1 year suggests that thymic recovery is likewise accelerated in non myeloablative compared to myeloablative regimens.

T-Cell recovery in adults and children following umbilical cord blood transplantation

T-cell reconstitution following allogeneic stem cell transplantation may involve thymic education of donor-derived precursors or peripheral expansion of mature T cells transferred in the graft. T cell-receptor excision circles (sjTRECs) are generated within the thymus and identify new thymic emigrants and those that have not divided. We measured quantitative and qualitative immunologic reconstitution and sjTREC levels in adult and pediatric recipients of umbilical cord blood transplants (UCBTs). sjTRECs were detected at normal levels in all children, starting 12 months after transplantation. sjTRECs were not detected until 18 months after transplantation in adults, and then only at a 3-fold lower level than expected for age. We used complementarity-determining region 3 (CDR3) spectratyping to measure changes in T cell-receptor diversity occurring with restoration of thymic function. T-cell repertoires were skewed in adults and children at 12 to 18 months after transplantation but recovered to near-normal diversity at 2 to 3 years post-UCBT. T-cell repertoires appeared more diverse earlier in children (at 1 to 2 years post-UCBT) than in adults (at 3 to 4 years post-UCBT). We conclude that early T-cell recovery after UCBT occurs primarily through peripheral expansion of adoptively transferred donor T cells and results in skewing of the T-cell repertoire. The reappearance of sjTREC-containing cells after UCBT is associated with increasing numbers of phenotypicaly naive T cells, improved mitogen and recall antigen responses, and diversification of the T-cell repertoire. The delay in central T-cell recovery in adults relative to children may be due to differences in thymic function resulting from age-related atrophy, graft-versus-host disease, or the pharmacologic effects of prophylaxis and treatment of graft-versus-host disease.

Prevention of graft-versus-host disease while preserving graft-versus-leukemia effect after selective depletion of host-reactive T cells by photodynamic cell purging process

In this study, we investigated the possibility of selective depletion of donor alloantigen-specific T cells from C57BL/6 (H-2(b)) mice to prevent graft-versus-host disease (GVHD). These cells were first activated with irradiated BALB/c (H-2(d)) host spleen cells in a 5-day mixed lymphocyte culture. Following this activation, a photoactive rhodamine derivative called 4,5-dibromorhodamine 123 (TH9402), was added. This compound is selectively retained in the mitochondria of activated host-reactive cells but not tumor- or third-party-specific resting cells. The treated cells were subsequently exposed to visible light (514 nm) to deplete the TH9402-enriched activated host-reactive cells. Treatment with photodynamic cell purging process (PDP) inhibited antihost responses measured by cytotoxic T lymphocytes (CTL) by 93%, and interferon-gamma production by 66%. By contrast, anti-BCL1 (BALB/c-origin leukemia/lymphoma) and anti-third-party C3H/HeJ (H-2(k)) responses were preserved. PDP-treated primed C57BL/6 cells were further tested in vivo. All lethally irradiated BALB/c mice inoculated with BCL1 cells and T-cell-depleted bone marrow cells developed leukemia by day +30, with 50% mortality by 100 days. All mice died of GVHD after addition of 5 x 10(6) untreated primed C57BL/6 cells. However, addition of same numbers of PDP-treated cells allowed 90% of the recipients to survive more than 100 days without detectable BCL1 tumor cells and free of GVHD. Moreover, PDP-treated primed C57BL/6 cells retained the ability to induce GVHD in the third-party C3H/HeJ mice. These data suggest that PDP can selectively deplete host alloantigen-specific T cells for GVHD prevention and immune and antileukemia function preserve.

Addition of a second, different allogeneic graft accelerates white cell and platelet engraftment after T-cell-depleted bone marrow transplantation

Significant delays in engraftment and lymphoid recovery are the 2 major challenges in cord blood transplantation. The cause for this delay is presumed to be the low numbers of hematopoietic precursors found in one unit of cord blood. One approach to increase the stem cell doses could be to combine cord blood units from different donors differing at the major histocompatibility complex (MHC). As a first step toward this goal, the kinetics of hematologic engraftment and immune reconstitution were compared between 1 unit (2.5 x 10(6) cells) of T-cell-depleted bone marrow cells from a single donor (C57BL/6 [H2(b)] or SJL/J [H2(s)]) and 2 units from different donors (C57BL/6 + SJL/J) after transplantation into lethally irradiated (8.5 Gy) BALB/c recipients (H2(d)). Addition of T-cell-depleted bone marrow from an MHC-mismatched allogeneic donor doubled the white blood counts compared with recipients of one single unit on days +10 and +14. Similar effects were also observed on platelets. The beneficial effect of additional cells on peripheral T-cell counts were first observed on day +14. Cells both from donors (C57BL/6 and/or SJL/J) and recipients (BALB/c) contributed to myeloid and lymphoid reconstitution. The chimeras containing cells from 3 strains of mice were able to mount a recall immune response. Our data suggest that combining stem cells from MHC-mismatched allogeneic donors is feasible, that it has beneficial effects on myeloid engraftment and T-cell phenotypic recovery, and that the long-term stable mixed chimeras are immunologically normal following T-cell-depleted bone marrow transplantation.

Mechanisms of tolerance induced by PG490-88 in a bone marrow transplantation model

BACKGROUND

PG490-88, a semisynthetic derivative of a novel compound PG490 (triptolide) purified from a Chinese herb (Tripterygium wilfordii Hook F), is effective in prevention of murine graft-versus-host disease (GVHD).

METHODS

PG490-88 was administrated into recipients in a model (B10.D2 [H2d, Mls-2b, Mls-3b]-->BALB/c [H2d, Mls-2a, Mls-3a]) of lethal GVHD. Tolerance was evaluated by transplantation of neonatal hearts. The mechanisms of tolerance were studied.

RESULTS

Host-specific tolerance was established in PG490-88-treated BALB/c recipients. Significant numbers of host reactive Vbeta3+ T cells (3.56+/-1.66% among CD4, 4.06+/-1.62% among CD8, P<0.0001 vs. normal BALB/c mice, P>0.05 vs. normal B10.D2 mice) were present in PG490-88-treated mice, suggesting that clonal deletion was not responsible for the observed tolerance. Spleen cells from PG490-88-treated mice could not respond to the host antigens measured by a popliteal lymph node weight gain assay. The unresponsiveness was unable to be overcome by supplementation of exogenous interleukin (IL)-2. Tolerant Vbeta3+ T cells obtained from PG490-88-treated mice proliferated normally to nonantigen-specific T cell receptor cross-linking. Neither antigen-specific nor nonantigen-specific suppressor cells were found in PG490-88-treated mice. The tolerant mice produced IL-4 rather than IL-2 and interferon (IFN)-gamma.

CONCLUSIONS

Host-specific tolerance induced by PG490-88 in a murine bone marrow transplantation model is not due to deletion of alloreactive cells. Moreover, suppressor cells are not involved in the maintenance of tolerance. Rather, PG490-88 seems to lead to allogeneic tolerance either through the induction of a state of antigen-specific anergy of the responding T cells or through the induction of T-helper cell, type II (TH2) responses.

A comparison of murine T-cell-depleted adult bone marrow and full-term fetal blood cells in hematopoietic engraftment and immune reconstitution

Umbilical cord blood has been increasingly used as a source of hematopoietic stem cells. A major area of concern for the use of cord blood transplantation is the delay in myeloid and lymphoid recovery. To directly compare myeloid and lymphoid recovery using an animal model of bone marrow and cord blood as sources of stem cells, hematopoietic engraftment and immune recovery were studied following infusion of T-cell-depleted adult bone marrow or full-term fetal blood cells, as a model of cord blood in a murine allogeneic transplantation model (C57BL/6 [H-2(b)] --> BALB/c [H-2(d)]). Allogeneic full-term fetal blood has poorer radioprotective capacity but greater long-term engraftment potential on a cell-to-cell basis compared with T-cell-depleted bone marrow. Allogeneic full-term fetal blood recipients had decreased absolute numbers of T, B, and dendritic cells compared with bone marrow recipients. Splenic T cells in allogeneic full-term fetal blood recipients proliferated poorly, were unable to generate cytotoxic effectors against third-party alloantigens in vitro, and failed to generate alloantigen-specific cytotoxic antibodies in vivo. In addition, reconstituting T cells in fetal blood recipients had decreased mouse T-cell receptor delta single-joint excision circles compared with bone marrow recipients. At a per-cell level, B cells from fetal blood recipients did not proliferate as well as those found in bone marrow recipients. These results suggest that full-term fetal blood can engraft allogeneic hosts across the major histocompatibility barrier with slower hematopoietic engraftment and impaired immune reconstitution.

Twenty-one-gauge needles provide more cellular samples than twenty-five-gauge needles in fine-needle aspiration biopsy of the thyroid but may not provide increased diagnostic accuracy

The technique of fine-needle aspiration (FNA) biopsy of the thyroid is important to evaluate malignancy in thyroid nodules. Eighty-five percent of thyroid FNA procedures lead to sufficient cellular material for diagnosis. With more cells aspirated, the chance of sufficiency for diagnosis increases. Large-bore needles lead to more cellular material being aspirated but bloodier specimens that may interfere with cytologic interpretation. Small-bore needles may result in too few cells for diagnosis. We conducted a randomized prospective study contrasting 21-gauge and 25-gauge needles in the evaluation of 50 consecutively enrolled nodules at our institution. In our investigation, 21-gauge needles more frequently provided superior biopsy specimens (50%) than did 25-gauge needles (18%). In the remaining specimens (32%), the 21-gauge and 25-gauge needles provided similar cellular material. The rate of sufficient samples was the same. We conclude that use of 21-gauge needles results in more cellular specimens but may not result in increased diagnostic accuracy.

[Repair and reconstruction of massively damaged wounds]

OBJECTIVE

To report repair and reconstruction of massively damaged wound under unusual condition.

METHODS

One hundred and forty-seven patients with deep tissue defects were admitted from January 1993 to December 2000, among them, 96 cases suffered from electrical injury, 18 cases with hot press injury, 18 cases with deep burns as a result of CO poisoning or epileptic seizure, 6 cases caused by chemical producing necrosis and wound infection, 3 cases with radiation injuries, 2 cases with chemical burn, 2 cases with explosive injury, 2 cases with frostbite. One hundred and seventy five wounds in 147 patients were repaired by transfer of local flap, forearm conversal island skin flap, pectoralis major myocutaneous flap, delto-pectoral skin flap, latissimus dorsi skin flap, gastroecnemius myocutaneous flap, anterior and posterior tibial artery island skin flap, and so on. The wound defect ranged from 1 cm x 1 cm to 20 cm x 28 cm, and the flaps were 1.5 cm x 2.0 cm to 22 cm x 30 cm. The necrotic tendon was replaced with acellular allogenic tendon simultaneously in 7 cases.

RESULTS

One hundred and sixty-nine flaps were survival with first intention, while necrosis of the tip of flap occurred in 6 cases. The transplantation of acellular allogenic tendon in all cases were survival. The function and configuration in 28 cases were satisfactory after 4 months to 8 years follow-up.

CONCLUSION

Various types of flaps are choosen according to the position, defect range and degree of wound, which is an ideal method to restore the function and to improve patients' living condition.

Triptolide, a novel immunosuppressive and anti-inflammatory agent purified from a Chinese herb Tripterygium wilfordii Hook F

Triptolide is a diterpenoid triepoxide purified from a Chinese herb Tripterygium Wilfordii Hook F (TWHF). TWHF has been used in traditional Chinese medicine for more than two thousand years. However, its potential value was recognized by the western medicine only after investigators observed the effectiveness of TWHF in the treatment of leprosy and rheumatoid arthritis. Triptolide has been identified as the major component responsible for the immunosuppressive and anti-inflammatory effects of TWHF. Triptolide inhibits both Ca(2+)-dependent and Ca(2+)-independent pathways and affects T cell activation through inhibition of interleukin-2 transcription at a site different from the target of cyclosporin A. Triptolide also has inhibitory effects on a variety of proinflammatory cytokines and mediators and on the expression of adhesion molecules by endothelial cells. Triptolide is effective for the treatment of a variety of autoimmune diseases and in prevention of allograft rejection and graft-versus-host disease in both animals and humans. Moreover, triptolide possesses antitumor and male anti-fertility effect. However, the toxicities of triptolide may be associated with renal, cardiac, hematopoietic and reproductive systems. Currently available data suggest that triptolide is a promising immunosuppressive and anti-inflammatory agent and should be explored further in autoimmune diseases and transplantation.

Graft-versus-host disease prevention by rapamycin: cellular mechanisms

Understanding the cellular mechanisms that lead to graft-versus-host disease (GVHD) may lead to alternative approaches in the prevention or therapy of this disease process. In this manuscript, we investigated the mechanisms of action of the immunosuppressive drug rapamycin for the prevention of GVHD. GVHD-free long-term survival was achieved in BALB/c (H2d, Mls-2a, Mls-3a) recipients of B10.D2/nSnJ (H-2d, Mls-2a, Mls-3a) bone marrow and spleen cells after a 30-day course of high-dose rapamycin (5 mg/kg per day). Low responses to recipient and third-party cells in a mixed lymphocyte reaction (MLR) were observed as well as decreased mature T-cell numbers in the spleen. This low response was not due to defective interleukin (IL)-2 production, because exogenous IL-2 did not improve the responses in the MLR. However, GVHD-free long-term survival was associated with a large number of infiltrating mononuclear cells in the target organs of GVHD. This observation suggested the possibility that these cells were responsible for suppressing the immune response. Regulatory cells, which could suppress both antirecipient and third-party responses in vitro, were demonstrated to be present in the spleens of these GVHD-free long-term survivors. These results suggest that in addition to impaired cellular immune function, the presence of non-specific regulatory cells (ie, suppression) may contribute to maintenance of GVHD-free long-term survival induced by short-course rapamycin.

Effects of aflatoxin and carotenoids on growth performance and immune response in mule ducklings

The purpose of this study was to investigate if carotenoids could alleviate the adverse effects caused by aflatoxin with respect to growth performance and immune response. In two experiments, a total of 320 mule ducklings were assigned to 5 treatments, i.e. control, aflatoxin B(1) (AFB(1)) 200 ppb, AFB(1) +beta-carotene (BC) 200 ppm, AFB(1)+BC 400 ppm, and AFB(1)+astaxanthin (AS) 200 ppm. In experiment 1, the addition of beta-carotene or astaxanthin in the diet containing AFB(1) 200 ppb resulted in a significant decrease in average daily gain as compared with the control. AFB(1) 200 ppb alone and the addition of BC or AS on top of AFB(1) resulted in a significantly lower daily feed intake than for the control group. There were no significant differences in relative organ weights among treatment groups. Both treatments of BC 400 ppm and AS 200 ppm had significantly more macrophages harvested per duck than the control and AFB(1) 200 ppb treatments. However, there were no significant differences among treatments in percentages of phagocytotic macrophages and number of Candida albican phagocytized by phagocytotic macrophages. In experiment 2, blood biochemical parameters and antibody titers were evaluated. There were no significant differences among treatments in total bilirubin content and alkaline phosphatase activity in the serum or in antibody titers against fowl cholera. However, AFB(1) treatment had the highest activities of AST and ALT in the serum. The addition of BC 400 ppm on top of AFB(1) significantly reduced ALT activity as compared with the AFB(1) 200 ppb treatment. These results suggest that carotenoids could provide a slightly toxic alleviating effect on growth performance, enhance the chemotaxis ability of macrophages, and reduce ALT activity elevated by AFB(1).

Prevention of graft-versus-host disease by a novel immunosuppressant, PG490-88, through inhibition of alloreactive T cell expansion

BACKGROUND

PG490-88 is a water soluble, semisynthetic derivative of a novel compound PG490 (triptolide) purified from the Chinese herb Tripterygium Wilfordii Hook F.

METHODS

PG490-88 was administrated into recipient mice in a model (B10.D2-->BALB/c) of lethal graft-versus-host disease (GVHD) to study the effects of PG490-88 on GVHD and on the various steps involved in the pathological course of GVHD.

RESULTS

Injection of PG490-88 i.p. at a dose of 0.535 mg/kg/day for the first 3 weeks after transplantation protected all the recipients from developing GVHD up to 100 days after transplantation. PG490-88 inhibited in vivo both CD4+Vbeta3+ and CD8+Vbeta3+ T cell (alloreactive T cells in this model) expansion in the spleen by 64.09 and 34.02%, respectively, at the time when Vbeta3+ cell expansion was in the logarithmic phase (day 3 after transplantation). Intracellular cytokine staining without further in vitro activation demonstrated 47.42% inhibition of IL-2 production among CD4+ spleen cells in PG490-88-treated mice as compared to GVHD control on day 3 after transplantation. In contrast, CD25 (alpha chain of interleukin-2 receptor) expression did not differ.

CONCLUSIONS

PG490-88 is highly effective in prevention of murine GVHD. The immunosuppressive effect of PG490-88 is mediated by inhibition of alloreactive T cell expansion through interleukin-2 production.

Chromium-induced glucose uptake, superoxide anion production, and phagocytosis in cultured pulmonary alveolar macrophages of weanling pigs

The dose-dependent effects of chromium chloride (CrCl3) and chromium picolinate (CrPic) were evaluated for their glucose uptake, superoxide anion (O2-) production, activity of glucose-6-phosphate dehydrogenase, and phagocytosis of incubated pulmonary alveolar macrophages in medium containing no or 5 x 10(-8)M insulin. Glucose uptake was found to increase in cells treated with 20 microg/L CrCl3. Incubation with 20 microg/L of CrPic enhanced glucose uptake and O2- production in an insulin-dependent manner. However, the inclusion of CrPic to 100 microg/L in the medium absent of insulin also increased O2- production. The activity of glucose-6-phosphate dehydrogenase was not affected by either the addition of Cr or insulin. The phagocytosis of Escherichia coli by macrophages was enhanced significantly (p < 0.05) in medium containing 10-100 microg/L CrCl3 or 20-100 microg/L CrPic in the presence of insulin. These results suggest that the addition of 10-20 microg/L CrCl3 enhances directly the cellular activity of macrophages, whereas the effect of CrPic requires the cooperative action of insulin in enhancing their glucose uptake and phagocytosis.

Managing an animal health emergency in Taipei China: foot and mouth disease

Taipei China had been free from foot and mouth disease (FMD) over 68 years before the disease occurred in March 1997. The first suspected case was recorded on a pig farm in the Hsinchu Prefecture on 14 March 1997. Based on clinical signs, gross histopathological findings, and results of enzyme-linked immunosorbent assays and reverse-transcriptase polymerase chain reaction tests, diagnosis of FMD was confirmed by the Taiwan Animal Health Research Institute on 19 March 1997 and was reconfirmed by the FMD World Reference Laboratory in Pirbright (United Kingdom), on 25 March 1997. By the end of July 1997, 6,147 pig farms (about a quarter of the pig farms in Taipei China), were affected. The disease was well under control within two months by means of stamping-out and blanket vaccination. The Government purchased 21 million doses of inactivated oil-adjuvant FMD vaccine, which allowed for two injections per pig and one injection of other cloven-hoofed animals. Before the vaccine was used, the stamping-out policy was implemented, ensuring that all pigs in the affected farms were destroyed. After blanket vaccination, a partial stamping-out policy was adopted, i.e. only pigs showing clinical signs were destroyed.

Fresh vs aged benzylpenicillin on non-IgE responses in mice

AIM

To study whether or not the freshly prepared benzylpenicillin could induce different non-IgE antibody response from aged benzylpenicillin.

METHODS

Antibody response was determined by enzyme-linked immunosorbent assay (ELISA). Antigen molecules recognized by antibodies and antigenic cross reactions were tested by hapten inhibition assay.

RESULTS

Isotypes of specific non-IgE antibodies induced by freshly prepared benzylpenicillin were mainly IgM, and then IgG and IgA. Some parts of specific antibodies recognized benzylpenicillin molecule and major parts combined with degraded or transforming products. Isotypes of antibodies responsible for cross reaction were mainly IgG between benzylpenicillin and ampicillin and IgM between benzylpenicillin and piperacillin.

CONCLUSION

Freshly prepared and aged benzylpenicillin induced different non-IgE antibody response.

Acute and subacute toxicity study of water-soluble polyalkylsulfonated C60 in rats

Polyalkylsulfonated C60, or FC4S, a highly water-soluble caged fullerene derivative, is believed to be a free radical remover or an antioxidant in biological systems. A 50 mg/ml aqueous solution was prepared as a master solution and administered to female Sprague-Dawley CD(Crl:CD(SD)BR) rats in a single-dose acute toxicity study or a 12-day subacute toxicity study where rats were given the solution daily. In a study of the median lethal dose (LD50), no rats died after oral administration, and thus FC4S was considered to be nontoxic if administered orally. In an LD50 intraperitoneal injection study, rats died within 30 hr after injection; the LD50 was determined to be approximately 600 mg per kilogram of body weight. Rats injected with the compound intraperitoneally or intravenously immediately eliminated the compound through the kidney; the kidney appeared to be the primary target organ. The compound induced a distinct lysosome-overload nephrosis, a phagolysosomal nephropathy characterized by a tinctorial difference between the outer cortex and the inner cortex and the medulla. The affected outer cortex showed a diffuse degeneration, with the presence of numerous large vacuoles and cytoplasmic aggregates in the tubular epithelium. The phagolysosomal nephropathy was detected in rats after acute exposure as well as in the surviving rats following 1 intraperitoneal injection of 500 mg/kg or intravenous injection of 100 mg/kg. Ultrastructural investigation revealed numerous membranous conglomerates characteristic of phagolysosomal and/or lysosomal inclusions in the cytoplasm of the renal tubular epithelium. These conglomerates were confined to the vacuole, electron-dense, and unevenly stained. They varied in size and shape and were fused or aggregated. Occasional phagolysosomes were also observed in the endothelial cells of the peritubular plexus. A preliminary study of microsomal enzyme activity analysis revealed a suppression effect of liver cytochrome P-450-dependent monooxygenase activities, including cytochrome P-450, cytochrome b5, and benzo(a)pyrene hydroxylase, but an increased level of kidney cytochrome P-450-dependent monooxygenase activities, including NADPH-cytochrome P-450 reductase. The significance of these enzyme alterations was not well determined. Further study is needed to clarify the correlation between the alterations of microsomal enzyme activity and the nephropathy of lysosomal overload-induced changes. These changes may serve as a biological marker in toxicity screening tests for this class of compound.