scholarly journals Evidence that Lyb-2 is critical to specific activation of B cells before they become responsive to T cell and other signals.

1982 ◽  
Vol 155 (5) ◽  
pp. 1309-1316 ◽  
Author(s):  
H Yakura ◽  
F W Shen ◽  
E Bourcet ◽  
E A Boyse

The generation of plaque-forming cells (PFC) to T-dependent antigen, but not to T-independent antigen, is reduced in vitro by Lyb-2 antibody. Monoclonal Lyb-2 antibody, added to Mishell-Dutton cultures within the first 2 d, but not later, greatly reduces the generation of alpha-sheep erythrocyte (SRBC) PFC from T-depleted spleen cells whether help is provided in the form of intact T cells or as soluble factors contained in mixed lymphocyte culture (MLC) supernatants. Generation of alpha-SRBC PFC from purified B cells, assisted by soluble factors in MLC and macrophage (P388D.1 cell) supernatants, is similarly reduced by Lyb-2 antibody. The initial 2-d period, during which cultures are diminishingly sensitive to reduction of PFC generation by Lyb-2 antibody, is not affected by the time at which such soluble factors are added. Thus, Lyb-2 cell surface molecules evidently do not function as receptors for these differentiative signals. Reduction of PFC generation by Lyb-2 antibody is antigen dependent in the sense that reduction of the PFC response to one antigen (SRBC) does not affect subsequent generation of PFC to a second antigen (horse erythrocytes) from the same cell population. These findings accord with the view that the Lyb-2 molecule participates in a B cell differentiative phase, probably proliferative, which begins with binding of antigen and precedes the phase in which B cells become fully receptive to signals from T and other cells.

1983 ◽  
Vol 157 (1) ◽  
pp. 141-154 ◽  
Author(s):  
P J Fink ◽  
I L Weissman ◽  
M J Bevan

To detect a strong cytotoxic T lymphocyte (CTL) response to minor histocompatibility (H) antigens in a 5-d mixed lymphocyte culture, it is necessary to use a responder that has been primed in vivo with antigen-bearing cells. It has previously been shown that minor-H-specific CTL can be primed in vivo both directly by foreign spleen cells and by presentation of foreign minor H antigens on host antigen-presenting cells. This latter route is evident in the phenomenon of cross-priming, in which H-2 heterozygous (A x B)F1 mice injected 2 wk previously with minor H-different H-2A (A') spleen cells generate both H-2A- and H-2B-restricted minor-H-specific CTL. In a study of the kinetics of direct- vs. cross-priming to minors in F1 mice, we have found that minor H-different T cells actually suppress the induction of virgin CTL capable of recognizing them. CTL activity measured from F1 mice 3-6 d after injection with viable A' spleen cells is largely H-2B restricted. The H-2A-restricted response recovers such that roughly equal A- and B-restricted activity is detected in mice as early as 8-10 d postinjection. This temporary hyporeactivity does not result from generalized immunosuppression--it is specific for those CTL that recognize the foreign minor H antigen in the context of the H-2 antigens on the injected spleen cells. The injected spleen cells that mediate this suppression are radiosensitive T cells; Lyt-2+ T cells are highly efficient at suppressing the induction of CTL in vivo. No graft vs. host reaction by the injected T cells appears to be required, as suppression of direct primed CTL can be mediated by spleen cells that are wholly tolerant of both host H-2 and minor H antigens. Suppression cannot be demonstrated by in vitro mixing experiments. Several possible mechanisms for haplotype-specific suppression are discussed, including inactivation of responding CTL by veto cells and in vivo sequestration of responding CTL by the injected spleen cells.


1983 ◽  
Vol 157 (1) ◽  
pp. 202-218 ◽  
Author(s):  
K Hayakawa ◽  
R R Hardy ◽  
D R Parks ◽  
L A Herzenberg

A small subpopulation of normal murine splenic B cells carrying all of the classic B cells markers (IgM, IgD, Ia, and ThB) also carries Ly-1, one of the major T cell surface molecules. This "Ly-1 B" subpopulation (identified and characterized by multiparameter FACS analyses) consists of relatively large, high IgM/low-IgD/low-Ly-1 lymphocytes that represent approximately 2% of the spleen cells in normal animals and, generally, 5-10% of spleen cells in NZB mice. Ly-1 B are clearly detectable in all normal mouse strains tested as well as NZB, CBA/N, other X-id mice and nude (nu/nu) mice. They are found primarily in the spleen; are either absent or very poorly represented in lymph node, bone marrow, and thymus; appear early during ontogeny, and comprise about a third of the small number of lymphocytes present in 5-d-old mice. NZB and (NZB x NZW)F1 mice have more Ly-1 B than all other strains and, furthermore, have a unique Ly-1 B population that secretes IgM when cultured under usual conditions in the absence of added antigen. The IgM secretion by these Ly-1 B cells accounts for the previously reported "spontaneous" IgM secretion by NZB spleen cells in culture. Studies with FACS-sorted cells show that the presence of Ly-1 on these IgM-secreting cells distinguishes them from the (Ly-1 negative) IgM-secreting "direct" plaque-forming cells generated in NZB mice after stimulation with sheep erythrocytes.


1974 ◽  
Vol 140 (6) ◽  
pp. 1646-1659 ◽  
Author(s):  
Richard J. Hodes ◽  
Barry S. Handwerger ◽  
William D. Terry

Two subpopulations separated from normal spleen have been shown to synergize as responding cells in the in vitro induction of specific cell-mediated cytotoxicity during the mixed lymphocyte culture (MLC). The synergizing populations are a nylon wool column-adherent and a nylon wool column-nonadherent fraction, enriched for B lymphocytes and T lymphocytes, respectively. When a mixture of these fractions is used as the responding cell population in MLC, greater cytotoxicity is generated than would be expected from the sum of activities generated in the two subpopulations sensitized separately. The synergy appears to occur at the sensitization rather than the effector phase. The synergizing cell which is contained in the nylon-adherent subpopulation is distinct from the cytotoxic effector T lymphocyte, is resistant to lysis by rabbit antimouse brain serum, and is unresponsive to phytohemagglutinin; its synergizing function could not be replaced by either plastic-adherent spleen cells or peritoneal exudate cells. These results suggest a role of a non-T-cell nonmacrophage population in the generation of cytotoxic activity.


1976 ◽  
Vol 144 (3) ◽  
pp. 810-820 ◽  
Author(s):  
R D Gordon ◽  
B J Mathieson ◽  
L E Samelson ◽  
E A Boyse ◽  
E Simpson

C57BL/6 and C57BL/10 female mice were grafted with skin from male or female donors incompatible for H-2 and/or non-H-2 antigens. Syngeneic male grafts applied after the rejection of primary allografts or syngeneic male grafts were rejected in accelerated (second set) fashion, whereas male grafts applied after primary female grafts were not. In addition, C57BL/10 female spleen cells, primed in vivo with an allogeneic (BALB/c, CBA, or B10.BR) male graft and challenged in vitro in mixed lymphocyte culture with syngeneic (C57BL/10) male cells, produced cytotoxic cells specific for syngeneic male target cells. We conclude that at least some component of H-Y is detected by female responder cells on allogeneic male cells, and that the second set cell mediated response to H-Y is not necessarily restricted by the H-2 haplotype of the primary sensitizing strain. Moreover, (CBA X B10) F1 females, primed in vivo with male cells of one parental haplotype (B10 or CBA) and challenged in vitro with male cells of the other parental haplotype (CBA or B10), fail to lyse male target cells of either parental haplotype. It therefore seems unlikely that a helper determinant shared between B10 and CBA is sufficient to explain the ability of CBA male cells to prime H-2-restricted T-cell cytotoxic responses by B10 females.


1979 ◽  
Vol 149 (4) ◽  
pp. 808-814 ◽  
Author(s):  
J D Waterfield ◽  
G Dennert ◽  
S L Swain ◽  
R W Dutton

Allospecific mouse T cells, positively selected in one-way mixed lymphocyte culture were maintained for 3 yr in tissue culture by sequential restimulation. Such proliferating T cells were tested for their ability to induce a positive allogeneic effect: activating B cells in an in vitro primary humoral response to sheep erythrocytes. It was found that such T lymphocytes could function as helper cells. Helper activity was shown to be specific in that the B cells activated had to share major histocompatibility complex (H-2) antigens with the strain used for selection of the cell line. Intra H-2 mapping showed that antigens coded in the IAk subregion played an important role in the induction of the positive allogeneic effect. Supernatant factors could substitute for the allogeneic T cells in activation of the in vitro humoral response. However, such supernates exhibited no strain specificity. Therefore, the specificity seen in the positive allogeneic effect is presumably a consequence of the alloantigenic recognition receptors intrinsic to the T cells, and not to any biologically restricting properties of the allogeneic effect factor itself.


1971 ◽  
Vol 133 (6) ◽  
pp. 1325-1333 ◽  
Author(s):  
Klaus-Ulrich Hartmann

Spleen cells of bone marrow chimeras (B cells) and of irradiated mice injected with thymus cells and heterologous erythrocytes (educated T cells) were mixed and cultured together (17). The number of PFC developing in these cultures was dependent both on the concentration of the B cells and of the educated T cells. In excess of T cells the number of developing PFC is linearly dependent on the number of B cells. At high concentrations of T cells more PFC developed; the increase in the number of PFC was greatest between the 3rd and 4th day of culture. Increased numbers of educated T cells also assisted the development of PFC directed against the erythrocytes. It is concluded that the T cells not only play a role during the triggering of the precursor cells but also during the time of proliferation of the B cells; close contact between B and T cells seems to be needed to allow the positive activity of the T cells.


1975 ◽  
Vol 142 (6) ◽  
pp. 1488-1508 ◽  
Author(s):  
B J Skidmore ◽  
D C Morrison ◽  
J M Chiller ◽  
W O Weigle

The C3H/HeJ mouse strain, previously shown to be a nonresponder to bacterial lipopolysaccharide (LPS)-induced mitogenesis in vitro, was demonstrated by the present studies to be competent to respond mitogenically to LPS, but only to LPS preparations obtained by selected extraction methods. These preparations appear to be confined to LPS isolated by mild extraction techniques, such as TCA or butanol. In contrast, those obtained by techniques utilizing phenol were only weakly stimulatory or completely nonstimulatory for spleen cells from the C3H/HeJ. All LPS preparations tested, on the other hand, were highly stimulatory for cells from another mouse strain, namely the C3H/St. The critical importance of the method of extraction of LPS on its mitogenic activity for C3H/HeJ cells was stressed by experiments in which LPS was prepared from Escherichia coli K235 using either of two procedures. In these experiments, phenol-extracted LPS, although mitogenic in the C3H/St, was completely nonstimulatory in the C3H/HeJ; whereas, butanol-extracted LPS was highly stimulatory in both strains of mice. This striking difference was attributed to a destructive effect of phenol on LPS, as demonstrated by the fact that treatment of butanol LPS with phenol resulted in a total loss of its mitogenic activity in the C3H/HeJ, but in only a partial loss in the C3H/St. In general, the mitogenic response observed with selected LPS preparations in the C3H/HeJ was quantitatively lower and more transient than that seen with the C3H/St, although qualitatively these responses appeared to be similar. This was evidenced by the observation that in both mouse strains LPS was a specific mitogen for B cells, a property which was also attributed in both strains to the same distinct structural region of the LPS molecule, that is lipid A. A preparation of LPS that failed to stimulate B cells from the C3H/HeJ nonetheless had the capacity to block activation of these B cells by a stimulatory preparation of LPS. These results strongly suggest that mitogenic stimulation of B cells by LPS is a function of the structural integrity of both the LPS molecule and putative B-cell receptors for LPS.


1973 ◽  
Vol 137 (2) ◽  
pp. 411-423 ◽  
Author(s):  
John W. Moorhead ◽  
Curla S. Walters ◽  
Henry N. Claman

Both thymus-derived (T) and bone marrow-derived (B) lymphocytes participate in the response to a hapten 4-hydroxy-3-iodo-5-nitrophenylacetic acid (NIP), coupled to a nonimmunogenic isologous carrier, mouse gamma globulin (MGG). Spleen cells from mice immunized with NIP-MGG show increased DNA synthesis in vitro when cultured with NIP-MGG. The participation of and requirement for T cells in the response was demonstrated by treating the spleen cells with anti-θ serum. This treatment resulted in a 77% inhibition of the antigen response. Furthermore, adoptively transferred normal thymus cells could be specifically "activated" by NIP-MGG in vivo and they responded secondarily to the antigen in vitro. The active participation of B cells in the secondary response was demonstrated by passing the immune spleen cells through a column coated with polyvalent anti-MGG serum. Column filtration reduced the number of NIP-specific plaque-forming cells and NIP-specific rosette-forming cells (both functions of B cells) and produced a 47% inhibition of the NIP-MGG response. The ability of the cells to respond to phytohemagglutinin (PHA) was not affected by column filtration showing that T cells were not being selectively removed. The participation of B cells in the in vitro NIP-MGG response was also shown by treatment of the spleen cells with antiserum specific for MGG and MGG determinants. B cells were removed by treatment with anti-IgM or polyvalent anti-MGG serum plus complement, resulting in a respective 46 and 49% inhibition of the response to NIP-MGG. (Treatment with anti-IgM serum had no effect on T cells.) The contribution of the hapten NIP to stimulation of T cells was investigated using NIP-MGG-activated thymus cells. These activated T cells responded in vitro very well to the NIP-MGG complex but not to the MGG carrier alone demonstrating the requirement of the hapten for T cell stimulation. The response was also partially inhibited (41%) by incubating the activated cells with NIP coupled to a single amino acid (epsilon-aminocaproic acid) before addition of NIP-MGG. These results demonstrated that T cells recognize the hapten NIP when it is coupled to the isologous carrier MGG.


1975 ◽  
Vol 141 (2) ◽  
pp. 508-512 ◽  
Author(s):  
P Häyry ◽  
L C Andersson

T cells triggered to blast transformation and proliferation by histoincompatible cells have the capacity of reverting "back" to lymphocytes. These "secondary" lymphocytes and their progeny cells are able to respond repeatedly to the same allogeneic stimulus in vitro.


1990 ◽  
Vol 10 (10) ◽  
pp. 5305-5313
Author(s):  
K X Luo ◽  
B M Sefton

p56lck, a lymphocyte-specific tyrosine protein kinase, binds to the cytoplasmic tails of the T-cell surface molecules CD4 and CD8. Cross-linking of CD4 expressed on the surface of murine thymocytes, splenocytes, and CD4+ T-cell lines induced tyrosine phosphorylation of p56lck dramatically. Cross-linking of CD8 stimulated tyrosine phosphorylation of p56lck strongly in murine L3 and GA4 cells, slightly in splenocytes, but not detectably in thymocytes. Differing effects of cross-linking on in vitro tyrosine kinase activity of p56lck were observed. An increase in the in vitro kinase activity of p56lck, when assayed with [Val5]-angiotensin II as an exogenous substrate, was found to accompany cross-linking of CD4 in three cell lines. No stimulation of the in vitro kinase activity, however, was observed after cross-linking of CD8 in L3 cells. The phosphorylation of p56lck at Tyr-394, the autophosphorylation site, was stimulated by cross-linking in all cell lines examined. Tyr-394 was the predominant site of increased tyrosine phosphorylation in two leukemic cell lines. In the other two cell lines, the phosphorylation of both Tyr-394 and an inhibitory site, Tyr-505, was found to increase. In contrast to cross-linking with antibodies, no striking increase in the tyrosine phosphorylation of p56lck was stimulated by antigenic stimulation. Therefore, the effect of antibody-induced aggregation of CD4 and CD8 on the tyrosine phosphorylation of p56lck differs, at least quantitatively, from what occurs during antigen-induced T-cell activation.


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