title: Inhibitory effects of B cells on antitumor immunity.
abstract: B-cell functions in antitumor immunity are not well understood. In this study, we evaluated the role of B cells in the development of antitumor immunity using Friend murine leukemia virus gag-expressing mouse EL-4 (EL-4 gag), D5 mouse melanoma, or MCA304 mouse sarcoma cells. To screen tumors for susceptibility to B-cell-deficient immune environments, spleen cells from naive C57BL/6 [wild-type (WT)] and B-cell knockout (BKO) mice were cultured with irradiated tumor cells in vitro. When cells were stimulated with EL-4 gag or D5 (but not MCA304 tumors), IFN-gamma production from CD8 T cells and natural killer cells was markedly decreased in WT compared with BKO cultures. IFN-gamma production was correlated with CD40 ligand expression on the tumor and inversely with interleukin-10 (IL-10) production by B cells. Sorted WT B cells produced more IL-10 than CD40 knockout (CD40KO) B cells when cocultured with EL-4 gag or D5 (but not MCA304). IFN-gamma production by BKO cells was reduced by the addition of sorted naive WT B cells (partially by CD40KO B cells) or recombinant mouse IL-10. In vivo tumor progression mirrored in vitro studies in that WT mice were unable to control tumor growth whereas EL-4 gag and D5 tumors (but not MCA304) were eliminated in BKO mice. Robust in vivo antitumor CTLs developed only in BKO tumor-challenged mice. Our studies provide the first mechanistic basis for the concept that B-cell depletion could therapeutically enhance antitumor immune responses to certain tumors by decreasing IL-10 production from B cells.
authors.affiliation: Center for Biologics Evaluation and Research, Division of Hematology, Food and Drug Administration, 1401 Rockville Pike, Rockville, MD 20852, USA.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Inoue
authors.forename: Wolfgang W
authors.initials: WW
authors.lastname: Leitner
authors.forename: Basil
authors.initials: B
authors.lastname: Golding
authors.forename: Dorothy
authors.initials: D
authors.lastname: Scott
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D019013:CD40 Antigens / Q000276:immunology; D023201:CD40 Ligand / Q000276:immunology; D016827:CD8 Antigens / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D015395:Histocompatibility Antigens Class I / Q000276:immunology; D007371:Interferon-gamma / Q000096:biosynthesis / Q000276:immunology; D016753:Interleukin-10 / Q000276:immunology; D007694:Killer Cells, Natural / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009374:Neoplasms, Experimental / Q000276:immunology*; D013154:Spleen / Q000276:immunology
chemical_list: D019013:CD40 Antigens; D016827:CD8 Antigens; C431698:CD8alpha antigen; D015395:Histocompatibility Antigens Class I; D016753:Interleukin-10; D023201:CD40 Ligand; D007371:Interferon-gamma