title: Ki-67 expression reveals strong, transient influenza specific CD4 T cell responses after adult vaccination.
abstract: Although previous studies have found minimal changes in CD4 T cell responses after vaccination of adults with trivalent inactivated influenza vaccine, daily sampling and monitoring of the proliferation marker Ki-67 have now been used to reveal that a substantial fraction of influenza-specific CD4 T cells respond to vaccination. At 4-6 days after vaccination, there is a sharp rise in the numbers of Ki-67-expressing PBMC that produce IFNγ, IL-2 and/or TNFα in vitro in response to influenza vaccine or peptide. Ki-67(+) cell numbers then decline rapidly, and 10 days after vaccination, both Ki-67(+) and overall influenza-specific cell numbers are similar to pre-vaccination levels. These results provide a tool for assessing the quality and quantity of CD4 T cell responses to different influenza vaccines, and raise the possibility that the anti-influenza T cell memory response may be qualitatively altered by vaccination, even if the overall memory cell numbers do not change significantly.
authors.affiliation: David H. Smith Center for Vaccine Biology and Immunology, Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, USA.
authors.forename: Xi
authors.initials: X
authors.lastname: Li
authors.forename: Hongyu
authors.initials: H
authors.lastname: Miao
authors.forename: Alicia
authors.initials: A
authors.lastname: Henn
authors.forename: David J
authors.initials: DJ
authors.lastname: Topham
authors.forename: Hulin
authors.initials: H
authors.lastname: Wu
authors.forename: Martin S
authors.initials: MS
authors.lastname: Zand
authors.forename: Tim R
authors.initials: TR
authors.lastname: Mosmann
mesh_terms: D000328:Adult; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D006801:Humans; D007156:Immunologic Memory; D007252:Influenza Vaccines / Q000276:immunology*; D007251:Influenza, Human / Q000517:prevention & control; D007371:Interferon-gamma; D007376:Interleukin-2 / Q000276:immunology; D019394:Ki-67 Antigen / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology
chemical_list: D007252:Influenza Vaccines; D007376:Interleukin-2; D019394:Ki-67 Antigen; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma