Primary T cell expansion and differentiation in vivo requires antigen presentation by B cells.
B cells are well documented as APC; however, their role in supporting and programming the T cell response in vivo is still unclear. Studies using B cell-deficient mice have given rise to contradictory results. We have used mixed BM chimeric mice to define the contribution that B cells make as APC. When the B cell compartment is deficient in MHC class II, while other APC are largely normal, T cell clonal expansion is significantly reduced and the differentiation of T cells into cytokine-secreting effector cells is impaired (in particular, Th2 cells). The development of the memory T cell populations is also decreased. Although MHC class II-mediated presentation by B cells was crucial for an optimal T cell response, neither a B cell-specific lack of CD40 (influencing costimulation) nor lymphotoxin alpha (influencing lymphoid tissue architecture) had any effect on the T cell response. We conclude that in vivo B cells provide extra and essential Ag presentation capacity over and above that provided by dendritic cells, optimizing expansion and allowing the generation of memory and effector T cells.
Crawford
Alison
A
Institute of Immunology and Infection Research, University of Edinburgh, Ashworth Laboratories, King's Buildings, West Mains Road, Edinburgh EH9 3JT, United Kingdom.
Macleod
Megan
M
Schumacher
Ton
T
Corlett
Louise
L
Gray
David
D
D000818:Animals; D030801:Animals, Genetically Modified; D017951:Antigen Presentation / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology* / Q000276:immunology* / Q000378:metabolism; D019013:CD40 Antigens / Q000378:metabolism; D002454:Cell Differentiation; D049109:Cell Proliferation; D002478:Cells, Cultured; D046528:Chimerism; D016207:Cytokines / Q000096:biosynthesis; D000949:Histocompatibility Antigens Class II / Q000235:genetics / Q000378:metabolism; D007156:Immunologic Memory / Q000276:immunology; D008233:Lymphotoxin-alpha / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL
D019013:CD40 Antigens; D016207:Cytokines; D000949:Histocompatibility Antigens Class II; D008233:Lymphotoxin-alpha