T cells within germinal centers are specific for the immunizing antigen.
A normal antibody response to T cell-dependent Ag requires physical contact between Ag-specific B and T cells. Because such Ag-specific cells are rare in vivo, we sought to identify an in vivo site where they physically contact each other. We examined the Ag specificity of T cells in germinal centers (GC) in lymph nodes, where it is known that Ag-specific B cells proliferate and mature. We investigated the Ag specificity of GC T cells in situ by examining two characteristics: 1) expression of certain V alpha and V beta TCR families; and 2) incorporation of bromodeoxyuridine into T cell DNA after exposure to Ag as an index of Ag-induced proliferation. When GC were induced in mice with cytochrome c and myelin basic protein, the GC T cells were found to preferentially express V alpha 11 and V beta 8 TCR families, which are, respectively, the dominant TCR families in these two responses. Furthermore, GC T cells have proliferated upon exposure to the Ag that induced GC formation. Taken together, these results demonstrate that GC must recruit and retain Ag-specific T cells, thus implicating the GC as an in vivo site where Ag-specific T and B cells interact.
Fuller
K A
KA
Department of Pathology and Medicine, Washington University School of Medicine, St. Louis, MO 63110.
Kanagawa
O
O
Nahm
M H
MH
D000818:Animals; D000939:Epitopes; D005260:Female; D007114:Immunization; D008198:Lymph Nodes / Q000166:cytology*; D008213:Lymphocyte Activation; D008297:Male; D051379:Mice; D004676:Myelin Basic Protein / Q000276:immunology; D010047:Ovalbumin / Q000276:immunology; D051381:Rats; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000032:analysis; D013601:T-Lymphocytes / Q000276:immunology*
D000939:Epitopes; D004676:Myelin Basic Protein; D016693:Receptors, Antigen, T-Cell, alpha-beta; D010047:Ovalbumin