B cells can prime naive CD4+ T cells in vivo in the absence of other professional antigen-presenting cells in a CD154-CD40-dependent manner.
The role of B cells as APC is well established. However, their ability to prime naive T cells in vivo has been difficult to examine because of the presence of dendritic cells. The current studies were undertaken to examine this issue in a model of adoptive transfer of antigen-specific B cells and T cells into histoincompatible Rag2(-/-) mice. By means of this system, we were able to demonstrate that antigen-specific B cells are competent APC for naive CD4(+) T cells specific for the same antigen. In vivo antigen presentation resulted in expansion of both CD4(+) T cells and B cells. The antigen-presenting function of the transferred B cells was dependent on the CD154-CD40 interaction, as transfer of CD154-deficient antigen-specific CD4(+) T cells or CD40-deficient B cells failed to induce T and B cell expansion in response to immunization. These results indicate that antigen-specific B cells have the capacity to induce primary T cell responses in the absence of other competent APC.
Rodríguez-Pinto
Daniel
D
Research Unit on Autoimmune Diseases, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, México D.F., México.
Moreno
José
J
D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology*; D015703:Antigens, CD / Q000276:immunology; D000945:Antigens, Differentiation, T-Lymphocyte / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D019013:CD40 Antigens / Q000276:immunology*; D023201:CD40 Ligand / Q000276:immunology*; D002454:Cell Differentiation / Q000276:immunology; D002455:Cell Division / Q000276:immunology; D016207:Cytokines / Q000096:biosynthesis / Q000235:genetics; D037181:Lectins, C-Type; D051379:Mice; D000099192:CD69 Antigens
D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D019013:CD40 Antigens; D023201:CD40 Ligand; D016207:Cytokines; D037181:Lectins, C-Type; D000099192:CD69 Antigens