biostudies-literatureUnknown78(12)Sugahara DRecent studies have demonstrated an essential role of Gag-specific CD4+ T-cell responses for viral control in individuals infected with human immunodeficiency virus type 1. However, little is known about epitope specificities and functional roles of the Gag-specific helper T-cell responses in terms of vaccine-induced protection against a pathogenic retroviral challenge. We have previously demonstrated that immunization with Friend murine leukemia virus (F-MuLV) Gag proteins protects mice against the fatal Friend retrovirus (FV) infection. We report here the structure of a protective T helper cell (Th) epitope, (I)VTWEAIAVDPPP, identified in the p15 (MA) region of F-MuLV Gag. In mice immunized with the Th epitope-harboring peptide or a vaccinia virus-expressed native full-length MA protein,Journal of virology6322-34https://www.ebi.ac.uk/biostudies/studies/S-EPMC416509biostudies-literatureIdentification of a protective CD4+ T-cell epitope in p15gag of Friend murine leukemia virus and role of the MA protein targeting the plasma membrane in immunogenicity.PMC416509Miyazawa MSugahara DTsuji-Kawahara SfalseIdentification of a protective CD4+ T-cell epitope in p15gag of Friend murine leukemia virus and role of the MA protein targeting the plasma membrane in immunogenicity.Recent studies have demonstrated an essential role of Gag-specific CD4+ T-cell responses for viral control in individuals infected with human immunodeficiency virus type 1. However, little is known about epitope specificities and functional roles of the Gag-specific helper T-cell responses in terms of vaccine-induced protection against a pathogenic retroviral challenge. We have previously demonstrated that immunization with Friend murine leukemia virus (F-MuLV) Gag proteins protects mice against the fatal Friend retrovirus (FV) infection. We report here the structure of a protective T helper cell (Th) epitope, (I)VTWEAIAVDPPP, identified in the p15 (MA) region of F-MuLV Gag. In mice immunized with the Th epitope-harboring peptide or a vaccinia virus-expressed native full-length MA protein,2004-01-01T00:00:00Z2004 Jun2025-04-20T00:34:20.318Z2019-03-27T00:50:28ZS-EPMC4165091516372610.1128/JVI.78.12.6322-6334.200410.1128/jvi.78.12.6322-6334.2004