title: Concerted antigen presentation by dendritic cells and B cells is necessary for optimal CD4 T-cell immunity in vivo.
abstract: The relative contributions of different types of antigen presenting cells to T-cell activation, expansion and induction of effector functions are still not fully understood. In order to evaluate the roles of dendritic versus B cells during these phases of a CD4 T-cell response in vivo, we adoptively transferred major histocompatibility complex class II restricted, T-cell receptor-transgenic CD4+ T cells into transgenic mice expressing selectively the T-cell restricting class II molecules on either dendritic cells, B cells or both. Upon immunization with peptide antigen, we observed that dendritic cells were sufficient to induce activation, expansion, interleukin-2 production and germinal centre migration of antigen-specific T cells, independently of other antigen-presenting cells. In contrast, neither resting nor activated B cells had similar antigen-presenting capacities in vivo. However, in double transgenic mice where both B cells and dendritic cells were capable of presenting antigen, T cells showed increased proliferation, expansion and cytokine production in vivo. Moreover, higher antigen-specific CD4 T-cell numbers accumulated in germinal centres. Our data demonstrate that dendritic cells are sufficient to activate naive CD4 T cells in vivo, but B cells subsequently can enhance CD4 T-cell expansion further.
authors: Institute for Immunology, Ludwig- Maximilians-University Munich, Munich, Germany.
authors: Petra
authors: P
authors: Kleindienst
authors: Thomas
authors: T
authors: Brocker
mesh_terms: D019264:Adoptive Transfer / Q000379:methods; D000818:Animals; D017951:Antigen Presentation / Q000276:immunology*; D000938:Antigen-Presenting Cells / Q000276:immunology; D015703:Antigens, CD / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology*; D015704:CD4 Antigens / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002455:Cell Division / Q000276:immunology; D048429:Cell Size; D003713:Dendritic Cells / Q000276:immunology*; D000949:Histocompatibility Antigens Class II / Q000276:immunology; D007111:Immunity, Cellular / Q000276:immunology; D007376:Interleukin-2 / Q000276:immunology; D008213:Lymphocyte Activation / Q000276:immunology; D051379:Mice; D008822:Mice, Transgenic; D011948:Receptors, Antigen, T-Cell / Q000276:immunology
chemical_list: D015703:Antigens, CD; D015704:CD4 Antigens; D000949:Histocompatibility Antigens Class II; D007376:Interleukin-2; D011948:Receptors, Antigen, T-Cell