title: Roles of CD4+ T-cell-independent and -dependent antibody responses in the control of influenza virus infection: evidence for noncognate CD4+ T-cell activities that enhance the therapeutic activity of antiviral antibodies.
abstract: Previous studies have indicated that B cells make a significant contribution to the resolution of influenza virus infection. To determine how B cells participate in the control of the infection, we transferred intact, major histocompatibility complex class II (MHC-II)-negative or B-cell receptor (BCR)-transgenic spleen cells into B-cell-deficient and CD8(+) T-cell-depleted muMT mice, termed muMT(-8), and tested them for ability to recover from infection. muMT(-8) mice that received no spleen cells invariably succumbed to the infection within 20 days, indicating that CD4(+) T-cell activities had no significant therapeutic activity on their own; in fact, they were harmful and decreased survival time. Interestingly, however, they became beneficial in the presence of antiviral antibody (Ab). Injection of MHC-II((-/-)) spleen cells, which can provide CD4(+) T-cell-independent (TI) but not T-cell-dependent (TD) activities, delayed mortality but only rarely resulted in clearance of the infection. By contrast, 80% of muMT(-8) mice injected with normal spleen cells survived and resolved the infection. Transfer of BCR-transgenic spleen cells, which contained approximately 10 times fewer virus-specific precursor B cells than normal spleen cells, had no significant impact on the course of the infection. Taken together, the results suggest that B cells contribute to the control of the infection mainly through production of virus-specific Abs and that the TD Ab response is therapeutically more effective than the TI response. In addition, CD4(+) T cells appear to contribute, apart from promoting the TD Ab response, by improving the therapeutic activity of Ab-mediated effector mechanisms.
authors.affiliation: Wistar Institute, 3601 Spruce Street, Philadelphia, PA 19104-4268, USA.
authors.forename: Krystyna
authors.initials: K
authors.lastname: Mozdzanowska
authors.forename: Michelle
authors.initials: M
authors.lastname: Furchner
authors.forename: Darya
authors.initials: D
authors.lastname: Zharikova
authors.forename: Jingqi
authors.initials: J
authors.lastname: Feng
authors.forename: Walter
authors.initials: W
authors.lastname: Gerhard
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000008:administration & dosage / Q000627:therapeutic use*; D000918:Antibody Specificity; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D004195:Disease Models, Animal; D000949:Histocompatibility Antigens Class II / Q000235:genetics; D009980:Influenza A virus / Q000276:immunology; D007274:Injections, Intraperitoneal; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009976:Orthomyxoviridae Infections / Q000276:immunology* / Q000628:therapy*
chemical_list: D000914:Antibodies, Viral; D000949:Histocompatibility Antigens Class II