Intrathymic presentation of nominal antigen by B cells.
Prenatal tolerization with TNBS leads to a transient increase in intrathymic TNP-specific B cells during the first postnatal week. To evaluate whether this may influence selection of the T cell repertoire and establishment of tolerance towards the neoself-determinant TNP, the capacity of intrathymic B cells to present TNP as well as an anti-TNP antibody (Sp6), which carries a recurrent idiotype, to thymocytes of prenatally untreated and TNBS-treated litters was explored. Depletion and reconstitution experiments revealed that in the thymus of 10-day-old litters Sp6 as well as TNP was presented exclusively by B cells. After stimulation with TNP-HRBC, B cells could still present the antigen, but depletion of B cells no longer abolished proliferation, i.e. after stimulation intrathymic B cells were no longer the only source for presentation of external antigen. B cells of prenatally tolerized mice differed inasmuch as they initiated proliferation only in response to Sp6, but not in response to the neoself-determinant TNP. Furthermore, after challenge with TNP in an immunogenic form, thymic as well as splenic B cells had lost the capacity to provide positive signals to T cells specific for the neoself determinant as well as to T cells specific for the cognate antibody. It is concluded that B cells are of importance in the intrathymic selection of the T cell repertoire and that they are involved in the process of tolerization towards nominal antigen.
Zöller
M
M
Institute for Radiology and Pathophysiology, German Cancer Research Center, Heidelberg.
D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology*; D005260:Female; D007108:Immune Tolerance; D008213:Lymphocyte Activation; D008212:Lymphocyte Depletion; D051379:Mice; D008807:Mice, Inbred BALB C; D011247:Pregnancy; D013601:T-Lymphocytes / Q000276:immunology; D013950:Thymus Gland / Q000276:immunology*; D014301:Trinitrobenzenes / Q000276:immunology
D014301:Trinitrobenzenes