The effect of combination therapy of cyclosporine with steroid on the production of gamma-interferon and interleukin-1 in kidney transplant recipients

The present study examined the effects of CsA administered with steroid in vivo on the capacity of kidney transplant recipient mononuclear cells to generate cytokines and their gene expression at the level of messenger RNA (mRNA). Peripheral blood mononuclear cells (PBMC) from CsA-Prednisolone (Pred) treated recipients displayed 66.9% inhibition (54.3 + 12.4 IU/ml, n = 42, p less than 0.01) of gamma-IFN production compared with normal individuals (134.6 + 18.6 IU/ml, n = 23). Azathioprine (Az)-Pred treated recipients displayed significantly less inhibition of gamma-IFN generation (96.0 + 16.1 IU/ml, n = 22, p less than 0.05) than CsA treated patients. Macrophages (m phi) from CsA-Pred treated recipients displayed 60.0% inhibition (5.1 + 0.7 U/ml, n = 20, p less than 21). These result were confirmed by the experiments using cDNA probe for gamma-IFN or IL-1 (alpha, beta). High levels of gamma-IFN mRNA in PHA-stimulated PBL or IL-1 (beta) mRNA in LPS-stimulated m phi were present in normal individuals, but not in CsA treated recipients as judged by hybridization to a cloned human gamma-IFN or IL-1 (beta) cDNA probe. These studies demonstrated that combination therapy of CsA with steroid inhibits both gamma-IFN and IL-1 gene expression at the level of mRNA at physiological concentration.     

The differential inhibitory effects exerted by cyclosporine and hydrocortisone on the activation of human cytotoxic lymphocytes by recombinant interleukin-2 versus allospecific CTL

Two immunosuppressive drugs, cyclosporine (CsA) and Hydrocortisone (Hy) were examined in parallel for their effect on the generation of cytolytic T lymphocytes (CTL). Peripheral blood lymphocytes (PBL) were stimulated with allogeneic cells to produce allospecific CTL, or with purified recombinant Interleukin 2 to activate lymphokine activated killer cells (LAK). CTL and LAK activity were measured in a 4 hr chromium release assay after 7 days of activation. Lysis by CTL was tested against stimulator PBL (not blasts) and LAK against fresh sarcoma tumor cells. At pharmacologic doses, CsA inhibited only CTL generation, and Hy inhibited only LAK. This greater understanding of the selective role, or roles, in vitro of CsA and Hy provides a basis by which to consider selective immune suppression--and, alternatively, the possibility of combining modalities for a more thorough immune suppression.     

Relative antigen-specific suppression in vitro of alloresponding human leukocytes by cellular delivery of cyclosporine

Human peripheral blood leukocytes (PBL) were incubated in Cyclosporine, washed, and then tested for their effect in two- and three-party in vitro cultures. In two-party mixed leukocyte reactions (MLRs), CsA pretreatment (70 ng/ml) of either responder or stimulator PBL produced a potent suppression in [3H]-thymidine uptake by responder PBL (greater than 100% specific inhibition). The ability of CsA-pretreated PBL to suppress the MLR was dependent on the concentration of CsA in which the PBL were incubated. CsA was more effective at suppressing the MLR when pretreated stimulator PBL were added, then when added directly to culture. In three-party cultures, CsA pretreatment of one stimulator population (50 ng/ml) resulted in cytotoxic T lymphocytes that effectively lysed target cells from the untreated population but not targets from the CsA-pretreated population. These results indicate that CsA-pretreated cells can be used to suppress an allogeneic response in a relatively antigen-specific manner, and may have implications for clinical transplantation.     

Effect of DSG on xenogeneic immune reactivity with special emphasis on human anti-pig cellular reactions in vitro

Abstract: The effect of the immunosuppressive drug 15-deoxyspergualin (DSG) on xenogeneic human anti-porcine cellular reactivity in vitro, including MLR induced proliferation, interleukin-2 (II-2) production, generation of cytotoxic cells, and the effect on antibody-dependent cellular cytotoxicity (ADCC), were compared with the effects of cyclosporin A (CsA) and/or FK506. The cytotoxic response was evaluated for both direct and indirect pathways for antigen presentation. In addition, the effects of DSG and CsA on antibody production to pig peripheral blood lymphocytes (PBL) in mice was studied. The degree of immunosuppression of xenogeneic and allogeneic cellular responses was compared. CsA and FK506 effectively inhibited proliferation and II-2 production induced by allogeneic human PBL or xenogeneic porcine PBL, whereas DSG did not have any effect on these responses. However, DSG suppressed both the allogeneic and xenogeneic in vitro induced cytotoxic responses, to the same level whether induced via the direct or indirect pathways of immune activation. In contrast, CsA inhibited cytotoxicity induced by xenogeneic cells via the direct but not via the indirect pathway. No effect of FK506 and DSG on ADCC was demonstrated.
A 5-day treatment with DSG or CsA of mice immunized with pig PBL partly suppressed antibody production. In DSG treated mice anti-pig PBL antibodies were produced, but titers were lower than in nontreated or CsA treated mice. The results indicate that DSG may be more effective than CsA/FK506 in inhibiting cytotoxic responses and antibody production induced by xenogeneic pig cells. A possible explanation could be that cytotoxicity induced via the indirect activation pathway of xenoreactivity is mediated to a high degree by CD3^- CD16⁺ (natural killer) NK-like cells, and that stimulation of these cells may be more sensitive to DSG than to CsA/FK506.     

Absence of CD4CD25 regulatory T cell expansion in renal transplanted patients treated in vivo with Belatacept mediated CD28-CD80/86 blockade

AIMS: Belatacept is a new recombinant molecule (CTLA4-Ig) that interferes with the second activation signal of T lymphocytes. CTLA4-Ig induced T cell allograft tolerance in rodents but not in primates. We examined the changes in peripheral lymphocyte subsets, including regulatory T cells, in renal transplant patients treated with Belatacept. METHODS: A cross-sectional immunological study was carried out 6 months after transplantation in 28 patients enrolled in the Belatacept phase II study. Eighteen patients received Belatacept, mycophenolate mofetil and steroids (Belatacept group), while the control group of 10 patients received cyclosporine, mycophenolate mofetil and steroids (CsA group). Lymphocyte subsets were examined by flow cytometry. Foxp3 mRNA expression was measured by quantitative PCR. RESULTS: The number of T lymphocytes and the percentage of CD3+ T cells were similar in both groups. However, the percentage of CD3+ CD4+ T cells was lower in the Belatacept group than in the control CsA group (B=42.5%+/-13.7 vs CsA=52.9%+/-9, p<0.005), and the percentage of CD3+ CD8+ cells was higher in the Belatacept group than in the control (B=32.9%+/-6.7 vs CsA=19.5%+/-8.2, p<0.0002). The percentage of CD19+ cells was similar in both groups. Among CD56+cells, only the percentage of CD16+ cells was significantly higher in the Belatacept group than in the control (B=82%+/-12 vs CsA=59.7%+/-25, p=0.01). Among CD4 and CD8 T cells the percentage of activated lymphocytes expressing CTLA4, HLA-DR or CD40L was similar in both groups. The percentage of CD4+CD25+ T cells was higher in the CsA group. The percentage of regulatory CD4+CD25+ cells with bright CD25 staining was similar in both groups (B=3.6+/-2.3% vs CsA=4.7+/-1.9%, ns) as was the expression of FoxP3. CONCLUSION: Our results indicated that Belatacept did not induce regulatory T cell expansion in vivo. We suggest that Belatacept treatment should be maintained after transplantation to allow graft acceptance.     

Influence of PGE2- and cAMP-modulating agents on human glioblastoma cell killing by interleukin-2-activated lymphocytes

Human glioblastoma cells secrete factors, such as prostaglandin E (PGE) and transforming growth factor beta type 2, which are capable of suppressing several immune functions. The present study investigated the effect of PGE2 and agents known to increase intracellular cyclic adenosine monophosphate (cAMP) levels on 1) the induction of lymphokine-activated killer (LAK) cell activity from the peripheral blood lymphocytes (PBL) of both normal and glioma patients and on 2) the cytolytic activities of tumor-infiltrating lymphocytes (TIL's) isolated from malignant gliomas after expansion in vitro with interleukin-2 (IL-2). Cytolytic activity was measured against autologous and allogeneic tumor cells and the natural killer-resistant Daudi cell line. The results demonstrate that PGE2 and agents known to increase intracellular cAMP levels can significantly suppress the IL-2-dependent generation of cytolytic activity from the PBL of normal and glioma patients and from glioblastoma-derived TIL's. The inhibitory effects of these agents could not be reduced by higher concentrations of IL-2 or by cyclic guanosine monophosphate. Although the suppressive effect of PGE2 was most significant during the early stages of LAK cell generation, an inhibitory effect was still evident when PGE2 was added directly to the cytotoxicity assay. Secretion of PGE2 by glioblastoma cells in vivo may regulate both the generation of an immune response and the effectiveness of adoptively transferred immune cells.     

Rejection following donor or recipient preoperative treatment with FTY720 in rat small bowel transplantation

BACKGROUND: Severe rejection of small bowel transplantation (SBTx) has been ascribed to abundant lymphoid tissues in the small intestine without well-established evidence. However, the role of donor lymphocytes in rejection is still unclear. The novel immunosuppressant, FTY720, is reported to transfer peripheral blood lymphocytes (PBLs) to lymphoid tissues such as mesenteric lymph nodes (MLNs) and Peyer patches (PP). In the present study, the number of donor lymphocytes in the graft was increased by FTY720, and the influence on rejection was studied in a rat model. Furthermore, the number of the PBL of recipient was decreased by FTY720 before SBTx and the effect on rejection was examined. MATERIALS AND METHODS: Orthotopic total SBTx was performed in Brown-Norway and Lewis rats. In the donor pretreatment study, FTY720 was administrated to donor rats 24 h prior to harvesting to increase the number of graft lymphocytes (FTY donor-pretreated group). In contrast, MLNs were surgically removed from the grafts to decrease the number of graft lymphocytes (MLN-resected group). In the recipient pretreatment study, FTY720 was administrated to recipient rats 24 h before SBTx to decrease recipient PBL (FTY group). In contrast, a subclinical dose of cyclosporine A (CsA) was administrated after SBTx (CsA group). Rats were administrated preoperative FTY720 combined with post-SBTx CsA (FTY+CsA group). Graft survival, pathology, lymphocyte count, and subtype were examined. RESULTS: In the donor pretreatment study, pretreatment with FTY720 did not enhance graft rejection. MLN resection did not prolong graft survival. In the recipient pretreatment study, FTY720 caused a significant reduction in the number of infiltrating lymphocytes in the graft, as well as the percentage of recipient CD4+ and CD25+ cells within the graft. FTY720 and CsA synergistically prolonged graft survival. CONCLUSION: SBTx rejection correlated with the number of recipient PBL, and not with the number of donor lymphocytes transplanted together with the graft. The pretreatment of the recipient with FTY720 was effective in the case of combined use of the low-dose postoperative CsA.     

Mesenteric lymph node Tgammadelta cells induced by gastrectomy in mice suppress cell-mediated immune response in vitro via released TGF-beta

We have shown previously that gastrectomy, but not laparotomy alone, severely impairs contact sensitivity responses in vivo and selectively alters cell trafficking in gut associated lymphatic tissue. Here, we investigate the immunological role of different subpopulations of mesenteric lymph node cells (MLNCs) in the inhibition of contact sensitivity as well as their suppressive mechanisms. Suppressive cells were isolated from the mesenteric lymph nodes of gastrectomized mice and were added to cultures of lymphocytes from mice immunized with trinitrophenyl-chloride. These MLNCs inhibited the proliferation of sensitized lymphocytes in response to antigen. Depletion experiments revealed that the suppressive MLNCs are Tgammadelta+ cells, but not Talphabeta+ cells. Neutralizing antibodies to IL-4, IL-10, and tissue growth factor-beta (TGF-beta) revealed that suppression was dependent on TGF-beta, but not the other cytokines. We conclude that surgical stress induced by gastrectomy causes accumulation of Tgammadelta+ lymphocytes in gut associated lymphatic tissue and that these cells suppress the cell-mediated response in vitro in an antigen-non specific manner via TGF-beta. This cytokine can possibly prevent in vivo the development of autoimmune responses following severe tissue trauma in the gastrointestinal tract.     

In vitro immunogenicity of cadaver donor bone marrow cells used for the induction of allograft acceptance in clinical transplantation.

BACKGROUND: The cascade of immunological effects brought about by donor bone marrow cell (DBMC) infusions to induce allograft acceptance in clinical transplantation is not fully understood. Aside from acting as immune responding and regulatory cells, the infused DBMC also may sensitize the recipient to the donor antigens. METHODS: To analyze this stimulatory activity of DBMC, in vitro mixed lymphocyte cultures (MLC) and cell-mediated lymphocytotoxicity (CML) culture systems analogous to the transplant model with DBMC infusion were used. RESULTS: When responding peripheral blood lymphocytes (PBL) from normal volunteers were placed in culture with suspensions of Ficoll-purified, T cell-depleted, un-irradiated allogeneic DBMC (NT-DBMC), a reaction was seen in both MLC and CML. However, when compared to allogeneic spleen cells as stimulating cells, the responses to NT-DBMC were of markedly lower magnitude and were not seen when the NT-DBMC was irradiated (3000 R). When responding PBL were stimulated with either NT-DBMC that had been previously cultured with irradiated cells from the responders for 1 week (activated NT-DBMC), NT-DBMC further depleted of CD15+ and glycophorin A-positive cells (NT-LP/DBMC), or purified CD34+ and CD2+ DBMC subsets, stronger lymphoproliferative and cytotoxic responses were observed. Moreover, these responses were not abrogated by irradiation of the stimulating DBMC subpopulations. Depletion of antigen-presenting cells by positive selection of CD3+ cells from the responding PBL abrogated MLC and CML reactivity, even when purified NT-LP/DBMC, the most stimulatory cells, were used. This latter observation was in contrast to the responses seen with cultures containing allogeneic stimulating spleen cell populations. This indicated the requirement for indirect alloantigen presentation, i.e., the failure of these DBMC to stimulate by direct alloantigen presentation. NT-DBMC was able to stimulate responding PBL in secondary MLC and CML responses with an equivalent magnitude, irrespective of whether the stimulators were spleen cells or NT-DBMC. Finally, the MLC and CML responses were inhibited by tacrolimus (FK506), mycophenolic acid (MPA), and cyclosporine (CsA) in a dose dependent manner, in contrast to previously observed refractoriness of DBMC preparations to these agents if DBMC was tested as responder cells or in modulatory assays. CONCLUSIONS: These results indicate that DBMC are able to function as effective in vitro stimulators, but only by indirect antigen presentation, and that the immune responses mediated by them can be down-regulated by their own inherent suppressive nature, an effect that can be enhanced by the presence of immunosuppressive drugs.     

Antitumor Killer Lymphocytes in the Peripheral Blood of a Patient with Transitional Cell Carcinoma of the Bladder

Background: Peripheral blood lymphocytes (PBL) from patients with bladder cancer also contain cells possessing cytotoxic activity against autologous tumor cells. These cells are phenotypically heterogenous and include natural killer (NK) and cytotoxic T cells. This study investigated the role of cytotoxic lymphocytes directed against autologous bladder cancer cells.
Methods: PBL were obtained at intervals before and after surgery and analyzed for cytotoxic activity against autologous bladder cancer cells in 4-hour⁵¹ Cr release assay. PBL stimulated with autologous tumor cells were also transformed with human T-lymphotropic virus type-1, establishing a cell line (KB31) which was analyzed for phenotype and cytotoxic activity against the autologous tumor cells.
Results: PBL preoperative cytotoxic activity was low, but increased after surgery. Cytotoxic activity was found not only against autologous bladder cancer cells, but also against heterologous bladder cancer (KK-47) and myeloid leukemia (K562) cells, with the highest activity against the heterologous cell lines. The cytotoxic activity of KB31 was 40|X% against autologous tumor cells 6 weeks after initiation of the cell line, but decreased to 5|X% by 6 months. This activity was lower than that against the other cell lines, and was similar to that of PBL in short-term culture. Fluorescence-activated cell sorter (FACS) analysis demonstrated that in KB31 cells at 6 weeks, CD8+ cells were dominant, but CD56+ cells predominated at 6 months.
Conclusion: These results suggest that the presence of cytotoxic activity in the peripheral blood of the patient was due to both cytotoxic T cells and NK cells. The cytotoxic activity was lowest prior to surgery and increased postoperatively.     

Human suppressor T cells induced in vitro with an autologous renal allograft-derived T cell line. II. Activity and specificity of a soluble suppressor factor

Human suppressor T cells induced by autologous mixed lymphocyte reaction (AMLR) using fresh responder PBL from a renal transplant recipient and an autologous irradiated antidonor CTL line (EE-1) established from a biopsy of the patient's own allograft were studied for the production of suppressor factors. The suppressor cell lines propagated (designated TsEE) were capable of inhibiting the in vitro generation of proliferative and cytotoxic responses of responder cells from the recipient or other individuals who shared HLA-B7 with TsEE cells, regardless of the stimulatory cell phenotype. Coculture of TsEE cells with the autologous irradiated EE-1 inducer cell line in vitro yielded a soluble factor (designated TsEEF) capable of inhibiting the generation of MLR and CTL responses, as well as mitogen-induced proliferative responses to PHA and PWM in an HLA-unrestricted manner. TsEEF also inhibited the replication of lymphoblastoid T cell lines (Molt-4 and HSB) but not B cell lines (SB and JC-EBV) or PBL stimulated with the B cell mitogen LPS. Control supernatants obtained from each of the cells used to generate TsEE in AMLR (i.e., EE-PBL and the EE-1 line) cultured alone or together for 48 hr demonstrated no suppressive activity in any of these test systems. TsEEF was nontoxic for lymphoid cells, was nondialyzable (greater than 12kDa), did not act by interfering with IL-1 or IL-2 utilization, and was negative for TNF and IFN-gamma activity. Functionally, the suppressive activity of TsEEF was dose-dependent, did not shift MLR kinetics, and could be absorbed by T cells. T cells incubated with TsEEF for 4 hr were unresponsive to subsequent mitogen or MLR stimulation. These findings indicate that, whereas T suppressor cell lines propagated from the circulation of a stable renal transplant recipient demonstrate class I HLA restriction, the activity of their soluble products is not HLA-restricted, and functionally inhibits T cell proliferation.     

Specific recognition of human leukemic cells by allogeneic T cell lines

Clinical and experimental data suggest a role for the immune response in preventing leukemic relapses following allogeneic bone marrow transplantation the graft-versus-leukemia (GVL) effect. In the context of an allogeneic BMT, a number of different immune mechanisms mediated by donor cells may be responsible for the GVL effect. We have approached this question by using limiting dilution cultures of alloactivated human lymphocytes to analyze the in vitro allogeneic cytolytic response against fresh allogeneic leukemia. Initial results in the limiting dilution assays with split culture analyses demonstrated frequent alloreactive cytolytic T lymphocyte precursors that destroyed remission peripheral blood lymphocytes and leukemic cells from the allogeneic leukemic patient. These assays also demonstrated frequent lymphokine-activated killer (LAK) cell precursors that lysed both the LAK sensitive Daudi line and the allogeneic leukemia. In these experiments, isolated cultures also showed cytolytic activity directed against the allogeneic leukemic blasts without activity against remission PBL, or the LAK-sensitive Daudi cell line. Two T cell lines (ABL1 and ABL2) isolated from an LDA, demonstrated this form of specificity, mediating destruction specifically against the allogeneic acute lymphoblastic leukemic cells. Both cell lines ABL1 and ABL2 were CD3+, TCR alpha beta +, and CD4+. These 2 cell lines mediated little or no cytotoxicity against a large panel of other targets tested (natural killer sensitive and resistant cell lines, allogeneic PBL, and allogeneic fresh leukemic blasts). Antibody-blocking experiments revealed a role for the CD3-TCR receptor of both cell lines in lysis of leukemic cells; the CD4 and MHC class II molecules were clearly involved in the lysis by the ABL1 cell line. Specificity of recognition for the allogeneic leukemic blasts was further confirmed by unlabeled target competitive inhibition studies. The mechanism of the preferential lysis of leukemia by the alloactivated T cell lines described in this paper remains uncertain. Nevertheless, these leukemic-specific populations provide a means by which the human GVL effect may be further studied in vitro.     

Blocking of interleukin-2 production, but not the tissue destruction induced by cytotoxic T cells, by cyclosporine

Cytotoxic T lymphocytes generated against epidermal alloantigen-1 (Epa-1), a tissue-restricted, non-H-2 alloantigen that is a target-cell determinant of both skin allograft rejection and cutaneous graft-versus-host reactions, directly produce full-thickness ulcerative skin lesions in Epa-1+ mice. Anti-Epa-1 CTL also indirectly cause extensive damage of "innocent bystander" tissue when injected admixed with Epa-1+ target cells into the skin of Epa-1- hosts. Unlike the direct destruction of host tissue by CTL in "immune lymphocyte transfer reactions" (TrR), "bystander reactions" (ByR) apparently are initiated by the release of lymphokines that recruit host inflammatory cells to the injection site. Treatment of CTL with cyclosporine in vitro prevents their production of lymphokines like interleukin 2 but has no effect on cell-mediated cytotoxicity. However, little is known about the function of CsA-treated CTL in vivo. We confirmed the differential effect of CsA on CTL function in vitro with bulk-culture anti-Epa-1 CTL-CsA pretreatment of CTL abrogated IL-2 production but did not affect CMC. Moreover, we found that CsA pretreatment did not affect the ability of CTL to evoke TrR, nor did it significantly impair their ability to mediate ByR. Therefore, when CTL are treated with CsA in such a way that they lose their capacity to produce IL-2, their cytotoxic activity in vitro as well as their ability to directly and indirectly mediate tissue destruction in vivo are left intact. These results suggest that the ability of CTL to mediate allograft rejection is not dependent on their ability to produce IL-2 and that CMC plays a role in the rejection process.     

Cytotoxicity of lymphocytes sensitized by autologous tumor cells in vitro, against autologous lung cancer cell lines

In order to obtain killer lymphocytes that would have a strong cytotoxicity against autologous tumor cells, we conducted a cytotoxic assay of effector cells cultured from human peripheral blood lymphocytes (PBL) using 10 cultured lung cancer cell lines as target cells. We present this result. (1) Lymphocytes obtained by 17 days mixed lymphocyte tumor cell culture (MLTC: Fresh PBL from lung cancer patients was mixed with irradiated autologous tumor cells in a medium, and cultured for 3 days. Irradiated allogeneic lymphocytes were then added, and cultured for 14 days) were cytotoxic against 4 of the 10 autologous lung cancer cell lines. (2) Lymphocytes obtained by 14 days MLTC and 3 more days culture in a medium containing interleukin 2 were cytotoxic against all 10 of the autologous lung cancer cell lines. These lymphocytes proliferated to 4.13 times of the original cell number, and their surface marker was OKT3+. These killer lymphocytes are expected to be effective in adoptive immunotherapy as effector cells.     

抗CD3与抗CD28单克隆抗体共刺激对淋巴细胞免疫活化基因mRNA表达的影响

目的　观察ＣＤ２８ 共刺激信号对淋巴细胞免疫活化基因表达的影响及环孢素Ａ（ＣｓＡ）对它们的抑制作用。方法　分离健康人外周血单个核细胞, 分别给予抗ＣＤ３ 单克隆抗体（ 抗ＣＤ３ｍＡｂ） 单刺激或抗ＣＤ３ ｍＡｂ＋ 抗ＣＤ２８ 单克隆抗体（抗ＣＤ２８ ｍＡｂ）共刺激培养; 加或不加入ＣｓＡ。于培养后６ ｈ 和２４ ｈ 收集细胞。以逆转录聚合酶链反应（ＲＴＰＣＲ） 检测βＡｃｔｉｎ、ＣＤ４０Ｌ、ｂｃｌｘＬ、ＴＧＦβ１ 、Ｆａｓ、ＦａｓＬ、穿孔素和颗粒酶ＢｍＲＮＡ 表达水平。结果　ＣＤ２８ 共刺激信号能显著增强免疫活化基因ｍＲＮＡ 的表达;ＣｓＡ 对ＦａｓＬ和颗粒酶Ｂ的ｍ ＲＮＡ表达能产生抑制, 而对共刺激后其余免疫活化基因的表达无明显抑制。结论　ＣＤ２８ 共刺激信号通过提高多种Ｔ 淋巴细胞相关的免疫活化基因的表达水平, 而使免疫反应的活化、增殖和效应过程均得到增强;ＣｓＡ 对这一过程并非完全无效, 仍可能具有调节作用。     

Induction of suppressor T cells by donor-specific blood transfusion (DST): establishment of a human T cell hybridoma producing an MLR suppressing factor]

We established a human T cell hybridoma producing a mixed lymphocyte reaction (MLR) suppressing factor. Three weeks after DST, peripheral blood lymphocytes (PBL) were obtained from a recipient and were cultured for 3 days with mitomycin C (MMC)-treated donor PBL. These lymphocytes were fused with an azaguanine-resistant mutant of a human T cell leukemic cell line (CCRF-CEMAG). Four weeks after fusion, approximately 30% of the wells showed hybridoma cell growth. To select hybridoma clones with suppressive activity, irradiated hybridoma clones were added as regulator cells to the mixed lymphocyte culture. After the cloning, one clone causing suppression of the donor-specific MLR was established (termed HK40: %MLR suppression = 38.9%). Unstimulated supernatant of HK40 showed no suppressive effect on the specific MLR. In contrast, supernatant of HK40 cultured with donor PBL for 24 hrs, suppressed the donor-specific MLR dose-dependently. This primed supernatant of HK40 markedly suppressed the specific MLR when added added at the culture initiation. These findings indicate that functional clones causing suppression of the alloantigen-specific MLR can be generated in patients receiving DST, and suggest that these clones may be essential to the prolongation of kidney allograft survival.     

Effect of cyclosporine on T lymphocyte development. Relationship to syngeneic graft-versus-host disease

This report investigates the effects of cyclosporine on the reconstitution of T lymphocytes after syngeneic bone marrow transplantation and its role in the development of a novel T cell-mediated autoimmune disease, syngeneic graft versus host disease. We analyzed the effect of CsA treatment on T lymphocyte differentiation during reconstitution after bone marrow transplantation and correlated the maturation of CD4+ and CD8+ T cell subsets with the onset of syngeneic GVHD. Administration of CsA following syngeneic bone marrow transplantation leads to a developmental arrest of mature CD4+ and CD8+ T lymphocytes in the thymus and a marked reduction in cells expressing the alpha beta T cell receptor. The reduction of CD4+ and CD8+ T cell subsets is also reflected in the peripheral lymphoid compartment with an altered CD4/CD8 ratio. Functional assessment of the cells revealed that CD8+ cells respond normally to mitogenic signalling whereas CD4+ cells exhibit marginal proliferative responses. Both subsets of T lymphocytes respond to syngeneic B lymphoblasts, comparable to the response of T lymphocytes from non-CsA-treated syngeneic BMT recipients, suggesting that autoreactive cells are produced despite CsA treatment. Following discontinuation of CsA, T cell differentiation in the thymus is rapidly restored to normal. However, concurrent with the onset of syngeneic GVHD, a compensatory insurgence of CD4+ T helper cells is observed.