title: B cells inhibit induction of T cell-dependent tumor immunity.
abstract: Cytotoxic T lymphocyte (CTL) mediated tumor immunity against major histocompatibility antigen (MHC) class I-positive but class II-negative tumors often requires help from CD4+ T cells. These CD4 cells are activated by MHC class II-positive cells that present tumor derived antigens. Considering that different antigen presenting cells, such as B cells, macrophages and dendritic cells compete for antigen and influence the outcome of an immune response, we analyzed tumor immunity in B cell-deficient mice. These mice appear normal with regard to T cell immunity and tolerance to some pure foreign antigens. We show here that the low immunogenicity of tumors is caused by B cells whose presence in the priming phase results in disabled CD4+ T cell help for CTL mediated tumor immunity. Instead, in the presence of B cells, a non-protective humoral immune response is induced. Our results may explain the enigmatic observation that tumor-reactive antibodies occur frequently in cancer patients.
authors.affiliation: Max-Delbrück-Center for Molecular Medicine, Berlin, FRG.
authors.forename: Z
authors.initials: Z
authors.lastname: Qin
authors.forename: G
authors.initials: G
authors.lastname: Richter
authors.forename: T
authors.initials: T
authors.lastname: Schüler
authors.forename: S
authors.initials: S
authors.lastname: Ibe
authors.forename: X
authors.initials: X
authors.lastname: Cao
authors.forename: T
authors.initials: T
authors.lastname: Blankenstein
mesh_terms: D000230:Adenocarcinoma / Q000276:immunology*; D000818:Animals; D000912:Antibodies, Neoplasm / Q000097:blood; D001402:B-Lymphocytes / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D005260:Female; D008325:Mammary Neoplasms, Experimental / Q000276:immunology*; D051379:Mice; D008817:Mice, Mutant Strains; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000912:Antibodies, Neoplasm