Changes in the activities of antigen-nonspecific helper and suppressor cells in rabbits after carbon tetrachloride-induced liver damage]

The peripheral blood helper and suppressor T cell activity in rabbits was studied by the method of concanavalin A-induced mitogenesis. Blood lymphocytes were stimulated in vitro with different concentrations of concanavalin A (8 micrograms/ml and 60 micrograms/ml, respectively). The effect of stimulated lymphocytes on proliferative response of allogenic lymphocytes to phytohaemagglutinin was investigated. The liver injury was induced by three-fold subcutaneous injections of carbon tetrachloride (1 ml of 50% oil solution per 1 kg of body mass) each third day. Histological analysis of the liver and T cell activity examinations was performed 2, 9, 16, 30 days after carbon tetrachloride administration. It was shown that the stages of the more pronounced liver injury and the less pronounced regeneration of the liver were accompanied by the increase of helper T cell activity. The stages of the intensive liver regeneration and the less pronounced liver injury were accompanied by the increase of suppressor T cell activity.     

Cyclosporine-induced transplantation unresponsiveness in rat cardiac allograft recipients: in vitro determination of helper and suppressor activity

Lymphocytes from spleen, peripheral blood, thymus, and lymph node of naive rats, nonimmunosuppressed recipients of MHC-incompatible heart grafts, and cyclosporine-treated recipients of MHC-incompatible heart grafts were tested for their ability to augment or suppress proliferation of naive cells in an in vitro MLR co-culture assay. Rats treated with cyclosporine for only 7 days maintained their grafts indefinitely. Potent suppressor activity was found in the peripheral blood and spleen of adult naive rats. In untreated engrafted rats, increased suppressor activity was found 1 wk after transplantation and increased helper activity 2 wk after transplantation. In contrast, subnormal helper and suppressor activity was found in cyclosporine-treated rats 1 wk after transplantation. Subsequently, suppressor activity peaked at 2 to 3 wk and helper activity at 4 wk after transplantation. Beyond 5 wk, the cyclosporine-treated rat was indistinguishable from naive ungrafted rats. Two types of suppressor activity were identified that differed in buoyant density and cyclophosphamide sensitivity. Neither suppressor activity demonstrated antigen specificity. These data suggest that one role of cyclosporine in this rat model is to delay the initial helper mechanisms until generalized suppressor activity is operable. The increased antigen-nonspecific activity is only transient, presumably until the final antigen-specific mechanisms become operative.     

T-cell subsets in peripheral blood of patients with newly diagnosed and posttreatment Hodgkin's and non-Hodgkin's lymphomas. Analysis by monoclonal antibody staining and flow cytometry

T-cell subsets in the peripheral blood of patients with Hodgkin's disease (HD) and non-Hodgkin's lymphomas (NHLs) were determined using anti T-cell monoclonal antibodies and flow cytometry. Forty HD patients and 30 NHL patients were evaluated; 76 normal blood donors served as controls. Newly diagnosed (untreated) HD and NHL patients had relatively normal values for percentages of total T-cells, helper cells and suppressor cells; their helper/suppressor ratios were also normal. The total lymphocyte count was normal for pretreatment HD, but lower than normal for NHL. Following treatment, both HD and NHL patients showed significantly decreased helper/suppressor ratios, caused by a significant decrease in the percentage of helper cells in HD patients and a significant increase in the percentage of suppressor cells in the small number of NHL patients studied. A small number of NHL patients, followed without specific treatment (passive follow-up), had relatively normal values for percentages of helper and suppressor cells and total T-cells. For both groups of patients off treatment, it is concluded that the lower helper/suppressor ratios are due to the prolonged effects of treatment (predominantly irradiation).     

Delineation of suppressor and helper activity within the OKT4-defined T lymphocyte subset in human newborns

Lymphocytes taken from the cord blood of newborns have active suppressor activity. Using in vitro PWM-stimulated cocultures, unfractionated T cells from newborns potently suppressed the expected immunoglobulin G (IgG) synthesis of their mothers' peripheral blood lymphocytes (PBL). Using positive and negative selection techniques, we characterized the active suppressor cell as expressing the OKT4+T8- phenotype. This cord blood lymphocyte subset suppressed maternal IgG synthesis after depletion of maternal suppressor cells, implicating the ability of newborn T cells to suppress directly rather than by inducing adult suppressor activity. Sublethal amounts (1500 rad) of gamma-irradiation fully abrogated the suppressor activity of cord blood T lymphocytes. Radioresistant cord T cells provided T cell help. Irradiation of cord OKT4+ and OKT8+ populations and their subsequent culture with maternal B cells determined that helper activity was a radioresistant subpopulation of the OKT4+ subset. These results indicate significant differences in the functional properties of T cell subsets from adults and newborns. Population studies determined that cord blood lymphocytes had a greater proportion of OKT4+ cells and lower proportion of OKT8+ cells than PBL from unrelated adults. The mothers tested had similar proportions of OKT4+ cells as their babies, and these levels are significantly higher than those of unrelated adults.     

Regulation of the immune response against UV-induced skin cancers: specificity of helper cells and their susceptibility to UV-induced suppressor cells

The purpose of this study was to determine the role of T helper (Th) cells in the immune response to UV-induced tumors. Repeated exposure of mice to UV radiation results in the production of suppressor T lymphocytes that facilitate tumor growth by inhibiting host immunity. To investigate whether the suppressor T cells inhibit the response to UV tumors by blocking the generation of Th, we employed an indirect method for measuring helper cell activity. We found that Th were produced in normal mice after immunization with UV-induced tumors. These Th appeared to be specific for the immunizing tumors, in contrast to the UV-induced suppressor cells, which recognize UV-induced tumors as a group. The suppressor T cells responsible for inhibiting tumor rejection have no effect on tumor-specific helper cell activity in vitro. However, UV-induced suppressor T cells transferred into unirradiated mice seem to block the generation of helper cell activity after immunization with UV-produced tumors. These results suggest the UV-induced suppressor cells may prevent tumor rejection by blocking the generation of Th.     

Altered levels of mononuclear leukocytes in tumor-bearing rats: decrease of helper T lymphocytes and increase of suppressor cells

In the spleen and peripheral blood of BN rats with progressive tumors, W3/25+ T helper cells were significantly reduced and OX8+ T suppressor/cytotoxic cells were significantly increased. The ratio of helper to suppressor elements was decreased to 1.6 from a ratio of 3 in normal BN rats without tumors, and this decreased ratio correlated with tumor growth. When tumors were eliminated in vivo by infusion of effector cells (W3/25+ T lymphocytes), the levels of W3/25+ and OX8+ T cells returned to normal and the ratio of helper to suppressor/cytotoxic cells in the spleen and peripheral blood reverted to 3.0 or higher. Macrophages and null cells, T-sIg-, were also elevated in the spleen and peripheral blood of rats bearing expanding tumors and returned to normal levels after cure. Assays of spleen cells for cell-mediated cytotoxicity in rats with large tumors revealed little or no specific cytotoxicity. Cytotoxic activity was high in spleen of rats cured of their neoplasms by infusion of helper cells.     

Suppressor cell regulation of encephalitogenic T cell lines: generation of suppressor macrophages with cyclosporin A and myelin basic protein.

Chronic relapsing experimental allergic encephalomyelitis (CR-EAE) can be adoptively transferred using myelin basic protein (BP)-specific helper T cell lines, and suppressor cells may be important in recovery from EAE. In order to generate suppressor cells, spleen cells obtained from BP-complete Freund's adjuvant (CFA) inoculated SJL/J mice and from normal mice were cultured for 7 days with medium, with cyclosporin A (CsA), or with CsA and antigen (BP or purified protein derivative of mycobacterium (PPD)). Cultured spleen cells were assayed for suppressor activity in vitro by coculture with BP-specific and PPD-specific helper T cell lines derived from SJL/J mice. Immunized donor spleen cells cultured with cyclosporin A (CsA) and BP were potent inhibitors of T cell line proliferation, and suppressor activity was increased 17-fold compared with control splenocytes. The number of suppressor cells required to suppress PPD-specific line proliferation by 50% (I50) was significantly higher than the number required to suppress BP-specific line proliferation, suggesting an antigen-specific component to the suppression. The major effector cell required for suppression was a large granular Mac-1+ cell with the functional characteristics of a macrophage. Suppressor activity persisted after depletion of Thy 1.2+ cells, but suppression was no longer antigen-specific, suggesting that culture of spleen cells with CsA and BP may generate suppressor macrophages which are antigen-nonspecific and Thy 1.2+ suppressor cells which are antigen-specific. These suppressor cells may be important in the regulation of CR-EAE and the techniques described for their generation may prove useful for treatment and prevention of disease.     

Interferon is the suppressor of hematopoiesis generated by stimulated lymphocytes in vitro

Lymphocytes that inhibit hematopoiesis may have a pathogenic role in some forms of bone marrow failure, and lymphocyte-mediated suppression may also be important in the normal regulation of bone marrow function. We have investigated the mechanism of in vitro suppression of hematopoiesis by T cells by using the methylcellulose colony culture system. Total peripheral blood T cells and separated subpopulations of helper (OKT4+) and suppressor (OKT8+) cells that have been stimulated by exposure to lectin suppress autologous colony formation by bone marrow myeloid (CFU-C) and erythroid (BFU-E) progenitor cells. Medium conditioned by these cells is also inhibitory, indicating that the suppressor activity is a soluble factor. A strong correlation existed for the concentration of interferon and the degree of hematopoietic suppressor activity in these supernatants; both activities peaked at days 3 to 5 of incubation and had sharply declined by day 7. Interferon production was enhanced by exposure of lymphocytes to sheep red blood cells during the rosetting procedure. Specific antiserum and a monoclonal antibody directed against gamma-(immune) interferon abrogated the inhibitory activity for hematopoiesis produced by lectin-stimulated T cells; an antiserum to alpha-interferon was generally much less effective in neutralizing activity. We infer from these results that gamma-interferon is the mediator of hematopoietic suppression generated by lectin-treated T-cells.     

T cell synergy in the primary MLR: proliferative kinetics, effector cell generation, and IL 2 production

A primary rat MLR was initiated, and on each of 8 consecutive days during the evolving culture, an aliquot of cells was separated into its constitutive helper/inducer (W3/25+) and suppressor/cytotoxic (OX8+) T cell subsets by a monoclonal antibody, Degalan-bead immunoadsorbent column technique. This allowed a detailed kinetic analysis of T cell proliferation, the generation of effector cells, and the production of IL 2 by each subset relative to net whole culture supernatant IL 2 activity. The primary MLR demonstrates an early period of helper/inducer cell proliferation, IL 2 production and accumulation, followed by a period of suppressor/cytotoxic cell (OX8+) proliferation and IL 2 consumption during which there are distinct waves of allospecific suppressor, followed by cytotoxic activity. If fresh T cells of the helper/inducer or suppressor/cytotoxic phenotype were preseparated and then cultured alone with irradiated allogeneic stimulator cells, proliferation was noted in both subsets despite no demonstrable IL 2 activity in cultures of the suppressor/cytotoxic cells. Finally, a suppressed primary MLR exhibited proliferative inhibition of both T cell subsets.     

Lymphocyte subset responses to repeated submaximal exercise in men

The effects of repeated bouts of submaximal cycle ergometry exercise on changes in the percentage of peripheral blood T-lymphocytes, the T-helper/inducer and T-cytotoxic/suppressor subsets, and natural killer (NK) cells were studied in 18 healthy young men who had no history of regular exercise training. Subjects were matched on the basis of maximal O2 uptake and assigned randomly to exercise or control groups, with controls resting quietly during the exercise sessions. The percentage of peripheral blood mononuclear leukocytes that reacted with monoclonal antibodies specific for T-lymphocytes (CD3+ cells), the helper/inducer subset (CD4+ cells) and cytotoxic/suppressor subset (CD8+ cells) of T-lymphocytes, and cells with NK activity (Leu7+ cells) were enumerated by fluorescence-activated flow cytometry for samples obtained immediately before and after exercise on days 1, 3, and 5 of a 5-day exercise regimen. The results of this study were mixed with decreases in the percentage of T-lymphocytes before vs. after exercise on days 1 and 3 (P less than 0.001), a decrease in the percentage of T-helper/inducer cells before vs. after exercise on day 3 (P less than 0.05), no effect of exercise on the percentage of T-cytotoxic/suppressor cells, and a marked increase in the percentage of NK cells after exercise on days 1 (P less than 0.05) and 3 (P less than 0.01). The total number of recovered NK cells in the mononuclear leukocyte fraction of blood also increased significantly after exercise on days 1 (P less than 0.05) and 3 (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)     

Immunoregulation after thermal injury: sequential appearance of I-J+, Ly-1 T suppressor inducer cells and Ly-2 T suppressor effector cells following thermal trauma in mice

Immunoregulation as a consequence of thermal injury was investigated by using a murine model involving a 30% surface area full thickness burn. Both allogeneic mixed lymphocyte reaction (MLR) and in vitro anti-SRBC responses were depressed from days 3 to 25 post-burn. Suppressor T cells could be identified in both systems between days 5 and 15. On day 5 post-burn, an Ly-1+,2-, I-J+ T cell is responsible for the majority of the suppression observed. This cell behaves like a T suppressor inducer T cell in that it must interact with an Ly-2+ cyclophosphamide-sensitive cell to manifest suppression. On day 7 post-burn, only Ly-1-,2+ suppressor T cells are found which can directly suppress the activity of Ly-1+,2- helper T cells. Thus, these cells behave as T suppressor effector cells. We suggest that feedback suppression is in operation after thermal injury, with functional suppressor inducer cells appearing on day 5 post-burn, leading to the appearance of T suppressor effector cells by 7 days post-burn. Recovery from post-burn immunosuppression occurs by day 25 post-burn and is associated with the appearance of V. villosa-adherent T cells, whose activity antagonizes that of the day 7 post-burn suppressor effector. These cells may represent contrasuppressor T cells, which could play a role in the restoration of immunocompetence after burn injury.     

Dose-dependent induction of immunologic enhancement and suppression after oral administration of antigen

The effects of feeding various quantities of a particulate antigen, sheep red blood cells (SRBC), on plaque-forming cells (PFC) in the spleen were determined. Mice were given various numbers of SRBC orally daily for 14 days, then injected with SRBC intravenously. Splenic IgA PFC responses to SRBC were enhanced in the mice fed 5 X 10(8) SRBC and splenic IgG PFC responses to SRBC were depressed in the mice fed 5 X 10(9) SRBC. Adoptive transfer experiments showed that enhancement of splenic IgA PFC responses and suppression of splenic IgG PFC responses were induced by the T-cell rich fraction from Peyer's patches (PP) and the spleen in 5 X 10(8) SRBC- and 5 X 10(9) SRBC-fed mice, respectively. Kinetic studies revealed that IgA helper cells or IgG suppressor cells appeared in PP 2 days after oral administration and 4 days after it in the spleen.     

Evaluation of the circulating and splenic lymphocyte subpopulations in patients with non-Hodgkin lymphomas and Hodgkin's disease using monoclonal antibodies

The number of B lymphocytes, T lymphocytes and their helper/inducer, cytotoxic/suppressor and NK/K subpopulations was measured in peripheral blood and spleen cell suspensions from patients with Hodgkin's disease (HD) in the active stage of the disease and in remission status, as well as in Non-Hodgkin lymphomas (NHL) in active stage of the disease. B lymphocytes were determined by direct immunofluorescence and T lymphocytes with the E rosette technique. Helper/inducer, cytotoxic/suppressor, and NK/K T lymphocytes were determined by indirect immunofluorescence with the monoclonal antibodies OKT4, OKT8 and Leu 7 (HNK1). In the same way, Lyt3 was used for determination of the total T lymphocytes. Whereas in peripheral blood of the NHL group an increase of B lymphocytes and a slight reduction of T lymphocytes could be observed, with normal distribution of the subpopulations, in patients with active HD as well as in those in remission, a marked absolute and relative decrease of T helper/inducer cells was found with normal cytotoxic/suppressor and NK/K proportion. In contrast to this, a significant increase of helper/inducer T lymphocytes with decreased cytotoxic/suppressor T proportion was found in spleen cell suspensions of patients with HD.     

Thalidomide and the immune system. 2. Changes in receptors on blood cells of a healthy volunteer.

Thalidomide (Thd) was given in two trials (total daily dose: 5 or 8 mg Thd/kg body weight, respectively) for five and three days to a healthy male volunteer, and various receptors were analyzed on white blood cells before, during and after (up to 30 days) the treatment period. There were neither marked deviations in the absolute number of total leukocytes nor in the percentage of total lymphocytes or monocytes throughout the study period. The most pronounced changes were observed in the surface receptors on CD4 ("helper cells") cells and leukocytes bearing the CD11b (Mac 1) and other integrin and adhesion receptors. Other changes included shifts in the ratio cytotoxic cells/suppressor cells as well as a reduction of the receptor density (passage from bright to dim) in T helper cells bearing CD45RO "memory" markers. Simultaneously, the number of B cells was found to be increased as was the percentage of some adhesion receptors on CD8+ cells. Unlike in previous experiments in which Thd was administered to marmoset monkeys, no effect could be seen in cells bearing the CD2 (LFA-2) epitope.     

T lymphocyte subsets in patients with malignant melanoma

Summary T lymphocyte subset profiles were determined by monoclonal antibodies on cryopreserved peripheral blood lymphocytes from 57 patients with malignant melanoma and 19 healthy controls. Quantitation of percentages of total T cells (OKT3.PAN), helper (OKT4.IND) or suppressor (OKT8.SUP) cells, and the ratio of helper/suppressor subsets revealed no correlation of these markers with stage of disease or clinical outcome. A sequential study of these markers on peripheral blood lymphocytes from three stage I melanoma patients with subsequent recurrent disease showed no fluctuations that could be correlated to tumor progression. This study indicates that there is no systemic imbalance in T cell subsets in malignant melanoma and that quantitation of these subsets cannot predict the clinical course of this disease.     

Cellular interactions of L-glutamic acid60-L-alanine30-L-tyrosine10 (GAT)-specific suppressor factors. I. Inhibition of the activity of GAT-specific helper T cell clones by monoclonal GAT-specific suppressor T cell factors

Considerable information concerning the serology and biochemistry of antigen-specific, T cell-derived suppressor factors has been obtained with the use of T cell hybridomas as a source of homogeneous material. Similarly, knowledge of helper T cell products and receptors is accumulating from studies of helper T cell clones and hybridomas. Our strategy for studying the mechanisms by which suppressor factors inhibit responses was to determine whether monoclonal suppressor factors could inhibit antibody responses specific for L-glutamic acid60-L-alanine30-L-tyrosine10 (GAT) in cultures containing unprimed splenic B cells, macrophages, and GAT-specific T cell clones as a source of helper activity. The MHC-restricted, two chain suppressor factors, GAT-TsF2, inhibited these responses if the helper T cell clones and suppressor factor were derived from H-2-compatible mice. Furthermore, responses were inhibited by briefly pulsing T cell clones with GAT-TsF2 in the presence of GAT, indicating that suppressor factors need not be present continuously. In addition, helper T cell clones adsorbed syngeneic, but not allogeneic, GAT-TsF2 in the presence of GAT. Adsorption also requires a shared antigenic specificity between the H-2b-derived helper T cells and TsF2 factor. Thus, helper T cells can serve as the cellular target of antigen-specific, MHC-restricted GAT-TsF2, and cloned helper T cells can be used as a homogeneous target population for analysis of the molecular mechanisms of T cell suppression.     

Functional analysis of mononuclear cells infiltrating into tumors. V. A. soluble factor involved in the regulation of cytotoxic/suppressor T cell infiltration into tumors

We have analyzed the mechanisms controlling the accumulation of cytotoxic/suppressor T lymphocytes in tumor tissues. We found that tumor-infiltrating helper/inducer T cells isolated from T-9 gliosarcoma-sensitized rats between 4 and 6 days after T-9 gliosarcoma inoculation produced a lymphocyte migration factor (LMF) during in vitro culture. Four peaks of LMF activity (A through D) were detected upon fractionation of LMF by using a Mono Q anion exchange column chromatography. Peak C exhibited the strongest activity among the four peaks of LMF. The action of peak C was chemotactic, but not chemokinetic. Peak C had an isoelectric point of 8.0 and a Mr of 26,000 Da. Only cytotoxic/suppressor T cells were found to be sensitive to peak C in vitro as well as in vivo. It is thus likely that peak C is responsible for the infiltration of cytotoxic/suppressor T cells into tumor tissues. The infiltration of lymphocytes into tumor tissues might also be regulated by the expression of lymphocyte sensitivity for LMF. The target molecule for LMF at 4 days may involve an asparagine-linked oligosaccharide.     

Reaginic antibody formation in the mouse. X. Possible role of suppressor T cells in transient IgE antibody responses.

The kinetics of IgE antibody response to alum-absorbed dinitrophenyl derivatives of ovalbumin (DNP-OA) was dependent on the dose of immunogen. A persistent IgE antibody response was obtained when high responder BDF1 mice were immunized with a minimum (0.05 microgram) dose. An increase of the immunogen to 10 microgram depressed IgE antibody responses but enhanced IgG antibody responses of both hapten and carrier specificities. Determination of T helper cell activity and B memory cells after immunization with different doses of antigen indicated that minimum immunogen was favorable for developing helper activity, whereas 1 to 10 microgram immunogen were more favorable than a 0.05-microgram dose for developing both IgE and IgG B memory cells. Nevertheless, neither helper T cells nor B memory cells in the spleen explains a transient IgE antibody response to a high (10 microgram) dose of DNP-OA. Evidence was obtained that immunization with 10 microgram OA induced generation of antigen-specific suppressor T cells, which were not detectable after immunization with 0.05 microgram OA. Transfer of suppressor T cells to DNP-OA-primed mice depressed both anti-hapten and anti-carrier IgE antibody responses. The results suggested strongly that suppressor T cells are involved in a transient IgE antibody response to a high-dose immunogen.     

Generation of suppressor cells in the response of human lymphocytes to a polysaccharide from Candida albicans

MPPS stimulation of human lymphocytes is characterized by a 2-way cooperation phenomenon, i.e., T help of B cells and B help of T cells. In this system suppressor cells are generated after 6 days of culture. They were characterized as Ia- T cells. Their suppressor activity affected both T and B cell stimulation, and it may involve 2 different mechanisms: direct cell suppression, and interaction with soluble helper factors.     

W3/25+ T cells mediate the induction of immunologic unresponsiveness in enhanced rat recipients of cardiac allografts

Cellular suppressor mechanisms developing during the induction of immunologic enhancement were studied in LEW rats immunized actively with BN spleen cells and passively with LEW anti-BN hyperimmune serum 11 and 10 days before receiving a (LEW X BN)F1 cardiac allograft, respectively. With this regimen, graft survival is prolonged from 7.4 +/- 0.5 days in unmodified, acutely rejecting hosts to 25 +/- 12 days in enhanced recipients, with one-third of the grafts surviving indefinitely. To test for suppressor capacities, 60 X 10(6) splenic T helper/inducer (W3/25+) and T suppressor/cytotoxic (OX8+) cells were adoptively transferred 7 and 14 days after transplantation either into unmodified syngeneic LEW animals that received (LEW X BN)F1 test grafts 24 hr later or into T cell-deprived B rats with indefinitely functioning heart transplants that were reconstituted with sensitized lymph node cells (100 X 10(6). W3/25+ T cells harvested on days 7 and 14 from enhanced recipients prolonged test graft survival in unmodified hosts (13.1 +/- 2.3 and 13.3 +/- 1.3 days, respectively, p less than 0.001) and delayed rejection in reconstituted B rats from 6.7 +/- 0.5 to 18.2 +/- 6.5 and 23.3 +/- 5.8 days, respectively (p less than 0.001). OX8+ and B lymphocytes had no suppressor activity. However, enzymatic stripping of the surfaces of W3/25+ cells abrogated suppressor function. Similarly, after i.p. treatment with cyclophosphamide, W3/25+ T cells lost their suppressor properties. Lack of donor specific but not third party alloaggressiveness was demonstrated by the profoundly diminished ability of W3/25+ lymphocytes from enhanced hosts to recreate rejection in nonreconstituted B rats, even when exogenous interleukin 2 was administered. After pronase treatment, however, W3/25+ T cells were capable of inducing immunoresponsiveness at a tempo similar to naive T helper cells (31.5 +/- 12.5 vs 32.8 +/- 7.9). Thus, the present studies provide evidence for the development of a specific W3/25+ suppressor cell in the induction of active and passive enhancement. Coincident abrogation of specific T effector alloaggressiveness is apparently mediated by surface-blocking factors.