title: Feline CD8+ T cell non-cytolytic anti-feline immunodeficiency virus activity mediated by a soluble factor(s).
abstract: Feline immunodeficiency virus (FIV) is more readily isolated from CD8+ T cell-depleted peripheral blood mononuclear cells (PBMC) of FIV-infected cats than from unfractionated PBMC cultures. However, it is not known whether feline CD8+ T cells down-regulate FIV expression by direct interaction with FIV-infected cells or via a soluble mediator. Furthermore, it is not known whether this anti-FIV activity involves a lytic or non-lytic mechanism. In the present study, we demonstrated that autologous and allogeneic CD8+ T cells from asymptomatic FIV-infected cats inhibited the replication of FIV in CD8+ T cell-depleted PBMC cultures in a dose-dependent manner. The inhibitory effect was mediated by a non-lytic mechanism, and was not dependent on direct cell-to-cell contact: an inhibitory effect was exerted by CD8+ T cells across a semi-permeable membrane, and an inhibitory activity was also present in cell-free supernatants from CD8+ T cells. These results suggest that this suppressive effect is mediated, at least in part, by soluble factors produced by CD8+ T cells.
authors.affiliation: Department of Veterinary Infectious Diseases, School of Veterinary Medicine and Animal Sciences, Kitasato University, Towada, Aomori, Japan. hohdatsu@vmas.kitasato-u.ac.jp
authors.forename: T
authors.initials: T
authors.lastname: Hohdatsu
authors.forename: M
authors.initials: M
authors.lastname: Okubo
authors.forename: H
authors.initials: H
authors.lastname: Koyama
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000276:immunology*; D016827:CD8 Antigens; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology* / Q000821:virology; D002415:Cats; D002450:Cell Communication / Q000276:immunology; D003602:Cytotoxicity, Immunologic; D016089:Immunodeficiency Virus, Feline / Q000502:physiology*; D014779:Virus Replication / Q000276:immunology*
chemical_list: D000914:Antibodies, Viral; D016827:CD8 Antigens