title: Development of Acquired Immunity following Repeated Respiratory Syncytial Virus Infections in Cotton Rats.
abstract: Respiratory syncytial virus (RSV) infections occur every year worldwide. Most infants are infected with RSV by one year of age and are reinfected because immune responses after the first infection are too weak to protect against subsequent infections. In the present study, immune responses against RSV were investigated in order to obtain a better understanding of repetitive RSV infections in cotton rats. No detectable neutralizing antibody (NT) was developed after the first infection, and the second infection was not prevented. The results of histological examinations revealed severe inflammation, viral antigens were detected around bronchial epithelial cells, and infectious viruses were recovered from lung homogenates. Following the second infection neutralizing antibodies were significantly elevated, and CD8+ cells were activated in response to RSV-F253-265. No viral antigens was detected thereafter in lung tissues and infectious viruses were not recovered. Similar results were obtained in the present study using the subgroups A and B. These results support the induction of humoral and cellular immune responses following repetitive infections with RSV; however, these responses were insufficient to eliminate viruses in the first and second infections.
authors.affiliation: Laboratory of Viral Infection I, Kitasato Institute for Life Sciences, Kitasato University, Shirokane 5-9-1, Minato-ku, Tokyo 108-8641, Japan.
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Yamaji
authors.affiliation: Health Center, Keio University, Kanagawa 223-8521, Japan.
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Yasui
authors.affiliation: Laboratory of Viral Infection I, Kitasato Institute for Life Sciences, Kitasato University, Shirokane 5-9-1, Minato-ku, Tokyo 108-8641, Japan.
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Nakayama
mesh_terms: D056704:Adaptive Immunity; D000818:Animals; D057134:Antibodies, Neutralizing / Q000276:immunology*; D000914:Antibodies, Viral / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D051381:Rats; D018357:Respiratory Syncytial Virus Infections / Q000276:immunology*; D012136:Respiratory Syncytial Viruses / Q000276:immunology*; D016205:Sigmodontinae
chemical_list: D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral