scholarly journals Ontogeny of culture-generated suppressor cells.

1979 ◽  
Vol 150 (6) ◽  
pp. 1359-1366 ◽  
Author(s):  
F M Rollwagen ◽  
O Stutman

Culture of murine lymphoid cells without added antigen results in the generation of cells which suppress a variety of in vitro immune responses, such as the mixed lymphocyte response (MLR) and the generation of alloreactive cytotoxic T cells (CTL). The ontogeny of this phenomenon was studied. Cells which suppressed the MLR after preculture were isolated from spleens and hematopoietic livers of fetal and young (less than 1 wk old) mice. On the other hand, the generation of alloreactive CTL could be suppressed only by precultured spleen cells taken from 1-w-old or older mice. The parallel between the development of the suppressor functions and the maturation of the responses they regulate, suggests a possible biological significance of the effect.

1974 ◽  
Vol 140 (3) ◽  
pp. 648-659 ◽  
Author(s):  
Judith A. Kapp ◽  
Carl W. Pierce ◽  
Stuart Schlossman ◽  
Baruj Benacerraf

In recent studies we have found that GAT not only fails to elicit a GAT-specific response in nonresponder mice but also specifically decreases the ability of nonresponder mice to develop a GAT-specific PFC response to a subsequent challenge with GAT bound to the immunogenic carrier, MBSA. Studies presented in this paper demonstrate that B cells from nonresponder, DBA/1 mice rendered unresponsive by GAT in vivo can respond in vitro to GAT-MBSA if exogenous, carrier-primed T cells are added to the cultures. The unresponsiveness was shown to be the result of impaired carrier-specific helper T-cell function in the spleen cells of GAT-primed mice. Spleen cells from GAT-primed mice specifically suppressed the GAT-specific PFC response of spleen cells from normal DBA/1 mice incubated with GAT-MBSA. This suppression was prevented by pretreatment of GAT-primed spleen cells with anti-θ serum plus C or X irradiation. Identification of the suppressor cells as T cells was confirmed by the demonstration that suppressor cells were confined to the fraction of the column-purified lymphocytes which contained θ-positive cells and a few non-Ig-bearing cells. The significance of these data to our understanding of Ir-gene regulation of the immune response is discussed.


2021 ◽  
Vol 12 ◽  
Author(s):  
Huimin Tao ◽  
Mingyu Liu ◽  
Yuan Wang ◽  
Shufeng Luo ◽  
Yongquan Xu ◽  
...  

Recent studies have demonstrated that splenic extramedullary hematopoiesis (EMH) is an important mechanism for the accumulation of myeloid-derived suppressor cells (MDSCs) in tumor tissues, and thus contributes to disease progression. Icaritin, a prenylflavonoid derivative from plants of the Epimedium genus, has been implicated as a novel immune-modulator that could prolong the survival of hepatocellular carcinoma (HCC) patients. However, it is unclear whether icaritin achieves its anti-tumor effects via the regulation of MDSCs generated by EMH in HCC. Here, we investigated the anti-tumor potential of icaritin and its mechanism of action in murine HCC. Icaritin suppressed tumor progression and significantly prolonged the survival of mice-bearing orthotopic and subcutaneous HCC tumors. Rather than exerting direct cytotoxic activity against tumor cells, icaritin significantly reduced the accumulation and activation of tumoral and splenic MDSCs, and increased the number and activity of cytotoxic T cells. Mechanistically, icaritin downregulates the tumor-associated splenic EMH, thereby reducing the generation and activation of MDSCs. The inhibitory effects of icaritin on human MDSCs in vitro were verified in short-term culture with cord-blood derived hematopoietic precursors. Furthermore, icaritin synergistically enhanced the therapeutic efficacy of immune checkpoint blockade therapy in HCC mice. These findings revealed that icaritin dampens tumoral immunosuppression to elicit anti-tumor immune responses by preventing MDSC generation via the attenuation of EMH. Thus, icaritin may serve as a novel adjuvant or even a stand-alone therapeutic agent for the effective treatment of HCC.


1969 ◽  
Vol 130 (2) ◽  
pp. 345-364 ◽  
Author(s):  
Carl W. Pierce

A cell suspension culture system combined with a procedure which separates most macrophages from lymphoid cells was used to investigate some of the cellular requirements for direct and indirect plaque-forming cell responses by nonprimed and primed mouse spleen cells in vitro. The plaque-forming cell response to heterologous erythrocytes in cultures of nonprimed spleen cells required both macrophages and lymphoid cells for its development. A significant indirect plaque-forming cell response did not develop in cultures of nonprimed spleen cells. In contrast, cultures of separated or macrophage-poor lymphoid cells from primed mice exhibited increasing responses relative to the response of unseparated spleen cells as the interval after priming increased. The cultures of separated lymphoid cells were not entirely free of phagocytic cells. Despite some evidence which suggests that these phagocytic cells had little function in the response, one cannot ascertain whether the lymphoid cells were responding directly to a second contact with antigen or whether the few contaminating phagocytic cells were performing a function essential to the response by the lymphoid cells. Physiologically different populations of cells appear to develop after priming and are able to respond in vitro in a macrophage-poor culture. Some of the properties of these populations suggest that they are "memory cell" pools containing precursors of direct and indirect plaque-forming cells highly susceptible to a second antigenic stimulus.


1974 ◽  
Vol 140 (4) ◽  
pp. 921-938 ◽  
Author(s):  
Carl W. Pierce ◽  
Judith A. Kapp ◽  
Susan M. Solliday ◽  
Martin E. Dorf ◽  
Baruj Benacerraf

The effects of alloantisera against leukocyte alloantigens on plaque-forming cell (PFC) responses to sheep erythrocytes and the terpolymer of L-glutamic acid60-L-alanine30-L-tyrosine10 (GAT) by mouse spleen cells in vitro have been investigated. Polyspecific antibodies against both H-2 and non-H-2 alloantigens on responding spleen cells suppressed both IgM and IgG PFC responses; antisera against alloantigens coded for by the K and I regions, but not the D region, of the H-2 complex also effectively suppressed PFC responses. The suppression was not due to cytotoxicity to the spleen cells or anti-immunoglobulin activity in the sera and was directly related to the amount of antiserum added to the cultures. The suppression was specific for spleen cells against which the alloantiserum was directed. The alloantisera suppressed responses most effectively when present during the first 24 h of incubation, and although not rendering lymphoid cells incapable of developing PFC responses after removal of noncell-bound antibody, did act by interfering with successful initiation of the PFC response. The alloantisera suppressed both IgM and IgG PFC responses when directed against alloantigens only on macrophages, but selectively suppressed IgG responses when directed against alloantigens only on lymphoid cells. The alloantisera did not interfere with the ability of macrophages to bind GAT or to support the viability of the lymphoid cells, but did interfere with the ability of macrophage-associated antigen to effectively stimulate antibody responses by the lymphoid cells. Possible mechanisms for the effects of alloantisera on macrophages and the selective suppression of IgG responses when the antisera are directed against alloantigens on lymphoid cells are discussed with reference to our current understanding of genetic restrictions governing cell interactions in the development of antibody responses in mice.


1969 ◽  
Vol 130 (2) ◽  
pp. 365-379 ◽  
Author(s):  
Carl W. Pierce

The effects of hyperimmune anti-sheep erythrocyte (SRBC) antibody on the plaque-forming cell (PFC) response to SRBC by mouse spleen cells in vitro were studied. Anti-SRBC antibody specifically suppressed the PFC response against SRBC. The degree of suppression was directly related to the amount of antibody added and was overcome by large amounts of antigen. Suppressive activity was absorbed from the sera by SRBC and could be partially eluted from the antigen by heat. The PFC response in cultures stimulated with antigen-antibody complexes prepared with high concentrations of antibody were suppressed; however, some complexes prepared at lower antibody concentrations stimulated greater responses than SRBC alone. Antibodies collected after four immunizations had greater suppressive ability than those collected after two immunizations. The degree of suppression was as great whether antibody was added at the initiation of the cultures or 24 hr later, suggesting that during the first 24 hr the culture system was antigen-dependent. Incubation of separated lymphoid cells with antibody did not impair their ability to develop a PFC response in vitro. However, if macrophages were incubated with antibody either before or after incubation with SRBC, the subsequent PFC response by lymphoid cells was suppressed. The data are consistent with the conclusion that antibody suppresses the PFC response in vitro by neutralizing the antigenic stimulus at the macrophage-dependent phase of the response.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yi Yu ◽  
Alejandra Vargas Valderrama ◽  
Zhongchao Han ◽  
Georges Uzan ◽  
Sina Naserian ◽  
...  

Abstract Background Mesenchymal stem cells (MSCs) exhibit active abilities to suppress or modulate deleterious immune responses by various molecular mechanisms. These cells are the subject of major translational efforts as cellular therapies for immune-related diseases and transplantations. Plenty of preclinical studies and clinical trials employing MSCs have shown promising safety and efficacy outcomes and also shed light on the modifications in the frequency and function of regulatory T cells (T regs). Nevertheless, the mechanisms underlying these observations are not well known. Direct cell contact, soluble factor production, and turning antigen-presenting cells into tolerogenic phenotypes, have been proposed to be among possible mechanisms by which MSCs produce an immunomodulatory environment for T reg expansion and activity. We and others demonstrated that adult bone marrow (BM)-MSCs suppress adaptive immune responses directly by inhibiting the proliferation of CD4+ helper and CD8+ cytotoxic T cells but also indirectly through the induction of T regs. In parallel, we demonstrated that fetal liver (FL)-MSCs demonstrates much longer-lasting immunomodulatory properties compared to BM-MSCs, by inhibiting directly the proliferation and activation of CD4+ and CD8+ T cells. Therefore, we investigated if FL-MSCs exert their strong immunosuppressive effect also indirectly through induction of T regs. Methods MSCs were obtained from FL and adult BM and characterized according to their surface antigen expression, their multilineage differentiation, and their proliferation potential. Using different in vitro combinations, we performed co-cultures of FL- or BM-MSCs and murine CD3+CD25−T cells to investigate immunosuppressive effects of MSCs on T cells and to quantify their capacity to induce functional T regs. Results We demonstrated that although both types of MSC display similar cell surface phenotypic profile and differentiation capacity, FL-MSCs have significantly higher proliferative capacity and ability to suppress both CD4+ and CD8+ murine T cell proliferation and to modulate them towards less active phenotypes than adult BM-MSCs. Moreover, their substantial suppressive effect was associated with an outstanding increase of functional CD4+CD25+Foxp3+ T regs compared to BM-MSCs. Conclusions These results highlight the immunosuppressive activity of FL-MSCs on T cells and show for the first time that one of the main immunoregulatory mechanisms of FL-MSCs passes through active and functional T reg induction.


1979 ◽  
Vol 149 (6) ◽  
pp. 1371-1378 ◽  
Author(s):  
B S Kim

Normal BALB/c spleen cells are unresponsive in vitro to the phosphorylcholine (PC) determinant in the presence of anti-idiotype antibodies specific for the TEPC-15 myeloma protein (T15) which carries an idiotypic determinant indistinguishable from that of most anti-PC antibodies in BALB/c mice. The possibility that idiotype-specific suppressor cells may be generated during the culture period was examined by coculturing the cells with untreated syngeneic spleen cells. Cells that had been preincubated with anti-T15 idiotype (anti-T15id) antibodies and a PC-containing antigen, R36a for 3 d, were capable of specifically suppressing the anti-PC response of fresh normal spleen cells, indicating that idiotype-specific suppressor cells were generated during the culture period. The presence of specific antigen also appeared to be necessary because anti-T15id antibodies and a control antigen, DNP-Lys-Ficoll, were not capable of generating such suppressor cells. Suppressor cells were induced only in the population of spleen cells nonadherent to nylon wool and the suppressive activity was abrogated by treatment with anti-Thy 1.2 serum and complement. These results indicate that anti-idiotype antibodies and specific antigen can generate idiotype-specific suppressor T cells in vitro. These in vitro results may reflect in vivo mechanisms of idiotype suppression.


1977 ◽  
Vol 146 (4) ◽  
pp. 970-985 ◽  
Author(s):  
C Waltenbaugh ◽  
J Thèze ◽  
J A Kapp ◽  
B Benacerraf

Injection of mice with L-glutamic acid50-L-tyrosine50 (GT)- or L-glutamic acid60-L-alanine30-L-tyrosine10 (GAT)-specific suppressor T-cell factor (GT-TsF or GAT-TsF) up to 5 wk before antigenic challenge challenge suppresses GT-methylated bovine serum albumin (MBSA) and GAT-MBSA plaque-forming cells responses. T suppressor cells are responsible for the suppression induced by the suppressive extract as demonstrated by adoptive transfer and sensitivity to anti-Thy-1 and complement treatment. We conclude that suppressive extract induces specific suppressor T cells. The material responsible for generation of suppressor T cells is a product of the I subregion of the H-2 complex. We have excluded that suppressive quantities of antigens are present in the extract. A/J mice, which can neither be suppressed by GT nor make GT-TsF can be suppressed by BALB/c GT-tsf. Spleen cells from BALB/c GT TsF-primed A/J mice can adoptively transfer suppression to normal syngeneic recipients. A/J mice appear to be genetically defective in cells involved in factor production. These results are discussed in the light of a two-step model for induction of antigen-specific suppressor cells.


1974 ◽  
Vol 139 (1) ◽  
pp. 193-207 ◽  
Author(s):  
Abraham I. Kook ◽  
Nathan Trainin

Experiments reported here were performed to understand the mechanism by which THF increases the immunocompetence of spleen cells from NTx mice. Dibutyryl cAMP or substances which increase intracellular levels of cAMP in lymphocytes such as Poly(A:U), theophylline, or PGE2 were shown to mimic the effect of THF and confer reactivity in an in vitro GvH response to spleen cells from NTx mice. Flufenamic acid, an antagonist to PGE2, was shown to inhibit the induction of competence by this substance. It was found that THF induces competence by activating membranal adenyl cyclase which leads to a rise in intracellular cAMP in thymus-derived cells only. These biochemical changes occur before antigenic stimulation and are unrelated to antigenic challenge. These findings indicate that THF exerts its effect via cAMP and are in agreement with the concepts which permit to classify THF as a thymus hormone.


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