title: Host differences in influenza-specific CD4 T cell and B cell responses are modulated by viral strain and route of immunization.
abstract: The antibody response to influenza infection is largely dependent on CD4 T cell help for B cells. Cognate signals and secreted factors provided by CD4 T cells drive B cell activation and regulate antibody isotype switching for optimal antiviral activity. Recently, we analyzed HLA-DR1 transgenic (DR1) mice and C57BL/10 (B10) mice after infection with influenza virus A/New Caledonia/20/99 (NC) and defined epitopes recognized by virus-specific CD4 T cells. Using this information in the current study, we demonstrate that the pattern of secretion of IL-2, IFN-γ, and IL-4 by CD4 T cells activated by NC infection is largely independent of epitope specificity and the magnitude of the epitope-specific response. Interestingly, however, the characteristics of the virus-specific CD4 T cell and the B cell response to NC infection differed in DR1 and B10 mice. The response in B10 mice featured predominantly IFN-γ-secreting CD4 T cells and strong IgG2b/IgG2c production. In contrast, in DR1 mice most CD4 T cells secreted IL-2 and IgG production was IgG1-biased. Infection of DR1 mice with influenza PR8 generated a response that was comparable to that in B10 mice, with predominantly IFN-γ-secreting CD4 T cells and greater numbers of IgG2c than IgG1 antibody-secreting cells. The response to intramuscular vaccination with inactivated NC was similar in DR1 and B10 mice; the majority of CD4 T cells secreted IL-2 and most IgG antibody-secreting cells produced IgG2b or IgG2c. Our findings identify inherent host influences on characteristics of the virus-specific CD4 T cell and B cell responses that are restricted to the lung environment. Furthermore, we show that these host influences are substantially modulated by the type of infecting virus via the early induction of innate factors. Our findings emphasize the importance of immunization strategy for demonstrating inherent host differences in CD4 T cell and B cell responses.
authors.affiliation: David H. Smith Center for Vaccine Biology and Immunology, Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York, United States of America.
authors.forename: Aarthi
authors.initials: A
authors.lastname: Sundararajan
authors.forename: Lifang
authors.initials: L
authors.lastname: Huan
authors.forename: Katherine A
authors.initials: KA
authors.lastname: Richards
authors.forename: Glendie
authors.initials: G
authors.lastname: Marcelin
authors.forename: Shabnam
authors.initials: S
authors.lastname: Alam
authors.forename: Hyemee
authors.initials: H
authors.lastname: Joo
authors.forename: Hongmei
authors.initials: H
authors.lastname: Yang
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Webby
authors.forename: David J
authors.initials: DJ
authors.lastname: Topham
authors.forename: Andrea J
authors.initials: AJ
authors.lastname: Sant
authors.forename: Mark Y
authors.initials: MY
authors.lastname: Sangster
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D006801:Humans; D007252:Influenza Vaccines / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic
chemical_list: D007252:Influenza Vaccines