title: Prolonged E55+ retrovirus expression in aged mice is associated with a decline in the anti-virus immune response.
abstract: E55+ murine leukemia retrovirus (E55+ MuLV) infection of young and aged C57BL/6 (B6) mice was used to investigate the relationship between increased incidences of infection and decreased immune responsiveness of elderly individuals. Young mice decreased E55+ MuLV burden to below detectable levels by 8 weeks postinfection (p.i.). In contrast, virus burden in aged mice did not reach undetectable levels until 20 weeks p.i. A significant T cell proliferative response to E55+ MuLV was detected from 2 to 12 weeks p.i. in young mice, but was never observed in aged mice. Both age groups demonstrated significant E55+ MuLV-specific T-cell-mediated cytotoxic responses at 3 and 4 weeks p.i. and virus neutralizing antibody titers at 2, 4, 8, and 12 weeks p.i. In both cases, responses were consistently higher in young mice (P < 0.04 and P < 0.02, respectively). These results demonstrate that the observed delay in E55+ MuLV clearance by aged mice is associated with an age-related decrease in the immune response to the virus.
authors.affiliation: Department of Microbiology and Immunology, MCP Hahnemann University School of Medicine, Philadelphia, Pennsylvania 19129, USA.
authors.forename: M
authors.initials: M
authors.lastname: elRefaei
authors.forename: K J
authors.initials: KJ
authors.lastname: Blank
authors.forename: D M
authors.initials: DM
authors.lastname: Murasko
mesh_terms: D000375:Aging / Q000276:immunology*; D000818:Animals; D000914:Antibodies, Viral / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology; D002455:Cell Division; D003602:Cytotoxicity, Immunologic; D009052:Leukemia Virus, Murine / Q000276:immunology*; D007942:Leukemia, Experimental / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D009500:Neutralization Tests; D012192:Retroviridae Infections / Q000276:immunology*; D013601:T-Lymphocytes / Q000166:cytology; D014412:Tumor Virus Infections / Q000276:immunology*
chemical_list: D000914:Antibodies, Viral