Effector functions and specificities of normal murine T cells stimulated by syngeneic blasts

Abstract

Large numbers of syngeneically stimulated T cells are easily obtained by stimulation of splenic T cell populations with irradiated lipopolysaccharide (LPS) blasts. Thus, proliferative T cell responses were obtained after stimulation with allogeneic LPS blasts, concanavalin A (Con A) blasts, normal spleen cells or peritoneal macrophages while only LPS and Con A blasts were competent syngeneic stimulators. The cytolytic activity of T cells stimulated with allogeneic LPS blasts was H-2 specific, while that of T cells stimulated with syngeneic LPS blasts was often completely nonspecific, and higher for LPS than for Con A blast target cells. In other experiments, "self" H-2K- and I-A-specific cytotoxic T cells were obtained, without apparent reasons for the development of either type of cytolytic cells. Stimulation of Lyt-2- T cells with syngeneic LPS blasts led to the generation of T helper effector cells which induced normal B cell proliferation in an H-2 restricted manner. This restriction was over-come, the proliferative responses were augmented and plaque-forming cell responses generated, through addition of Con A to the cultures. The results imply the ability of B blasts to induce stimulation of syngeneic T cells, and generation of effector cells displaying cytolytic and helper activity. This phenomenon might play a role in the regulation of the immune system.

Protective effect of a T-cell-dependent immunosuppressive, B-cell-mitogenic protein (F3'EP-Si, or P90) produced by Streptococcus intermedius

“…The present model assumes that a relationship between the two previously described possible mechanisms for immunosuppression, i.e., negative feedback by antibodies and induction of suppressor cells, must be take into consideration for an understanding of the complex relationship between microorganisms and infected hosts. Various examples of this relationship have been reported: the induction of helper and suppressor T cells may be achieved by direct stimulation of T cells by B blasts, and T-cell activation may be mediated by membrane-associated molecules expressed at high levels on activated B cells, such as Ig itself (25) or Ia antigens (10). Alternatively or simultaneously, antibody-induced immunosuppression may occur.…”

Analysis of T cell receptor Vβ gene usage in primary mixed lymphocyte reactions : evidence for directive usage by different antigen‐presenting cells and Mls‐like determinants on T cell blasts

“…It is well known that Ia+ allogeneic DC [22, 271 and M@[28, 291 as well as LPS[30,31] and anti-Ig[32]-sensitized B cell blasts are potent APC in primary MLR. Also activated Ia-Tcells are competent APC for resting Tcells in primary MLR[31].…”

“…It is well known that Ia+ allogeneic DC [22, 271 and M@[28, 291 as well as LPS[30,31] and anti-Ig[32]-sensitized B cell blasts are potent APC in primary MLR. Also activated Ia-Tcells are competent APC for resting Tcells in primary MLR[31]. To address the question whether different types of allogeneic APC have the capacity to influence the usage of certain TcR, Vp genes given T cell populations were subdivided and stimulated, in parallel, with SC, DC, B cell blasts and T cell blasts expressing the same allo-MHC products.Fig.…”

Degeneracy of H‐2 recognition by cytotoxic T lymphocytes: 10% of the total repertoire is “specific” for a given haplotype and up to 1% is self‐H‐2 reactive

“…Very low numbers of T cells can also be induced to proliferate using syngeneic nonmanipulated stimulator cells in a primary syngeneic MLR [21-231. Syngeneic stimulator cells expressing high levels of self-MHC determinants such as dendritic cells [24, 251 o r Con A and LPS blasts [26] would, however, induce syngeneic MLR responses, similar to those of allogeneic MLR responses. It is likely therefore that the high frequency of self-reactive CTL obtained after polyclonal induction are of low affinity, and that normal levels of self-MHC determinants are not sufficient to trigger these cells.…”