Germinal center B cells present antigen obtained in vivo to T cells in vitro and stimulate mixed lymphocyte reactions.
In the present study we sought to test the ability of GC B cells to activate T cells by antigen presentation and mixed lymphocyte reactions. The first set of experiments demonstrated that GC B cells obtained three or more weeks after immunization could induce IL 2 production by T cells only by adding antigen to the cell cultures. In the next (table; see text) series, it was demonstrated that GC B cells isolated as early as 1 day and for over a week following an antigenic challenge with OVA (i.e. where they obtained antigen from the FDC-derived iccosomes in vivo), were able to stimulate high levels of IL 2 production in the absence of exogenous OVA. This response was maximal on Day 5 which corresponded precisely with the keinetics of the ultrastructural studies which document the uptake of antigen by GC B cells in vivo (see Szakal et. al, this volume). Furthermore, it was shown that the FDC-derived antigen was remarkably immunogenic when compared with exogenous antigen. The data from the MLRs demonstrated that GC B cells, which are low density cells, are potent stimulators of T cells compared to the resting, low density B cells. In addition, GC B cells even stimulated a significant syngeneic response. These results indicate that GC B cells can present antigen and interact with T cells efficiently. This is believed to be important in the germinal center reaction and in the induction and maintenance of the immune responses.
Kosco
M H
MH
Department of Microbiology and Immunology, Medical College of Virginia, VCU, Richmond 23298.
Monfalcone
A P
AP
Szakal
A K
AK
Tew
J G
JG
D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology*; D066298:In Vitro Techniques; D007376:Interleukin-2 / Q000096:biosynthesis; D008198:Lymph Nodes / Q000166:cytology; D008213:Lymphocyte Activation; D007959:Lymphocyte Culture Test, Mixed; D051379:Mice; D013601:T-Lymphocytes / Q000276:immunology*; D013997:Time Factors
D007376:Interleukin-2