title: Ability of CD8(+) T cell anti-feline immunodeficiency virus activity correlated with peripheral CD4(+) T cell counts and plasma viremia.
abstract: In the host defense mechanism against feline immunodeficiency virus (FIV) infection, CD8(+) T cells specifically attack virus-infected cells and suppress the replication of the virus in a non-cytolytic manner by secreting soluble factors. In this study, we measured CD8(+) T cell anti-FIV activity in 30 FIV-infected cats. We investigated its relationship with the number of peripheral blood lymphocytes, particularly the CD4(+) T cell and CD8(+) T cell counts, and the relationship between anti-FIV activity and the number of T cells of CD8alpha(+)beta(lo) and CD8alpha(+)beta(-) phenotypes. A clearly significant correlation was observed between anti-FIV activity and the number of CD4(+) T cells. A weaker anti-FIV activity was associated with a greater decrease in the number of CD4(+) T cells. However, there was no significant correlation between anti-FIV activity and the number of B or CD8(+) T cells. Compared with SPF cats, FIV-infected cats had significantly higher CD8alpha(+)beta(lo) T cell and CD8alpha(+)beta(-) T cell counts, but, no significant correlation was observed between these cell counts and anti-FIV activity. This anti-FIV activity significantly correlated with plasma viremia, which was detected in cats with a weak anti-FIV activity. These results suggest that the anti-FIV activity of CD8(+) T cells plays an important role in plasma viremia and the maintenance of CD4(+) T cells in the body. It is unlikely that CD8alpha(+)beta(lo) or CD8alpha(+)beta(-) T cells appearing after FIV infection represent a phenotype of CD8(+) cells with anti-FIV activity.
authors: Department of Veterinary Infectious Diseases, School of Veterinary Medicine and Animal Sciences, Kitasato University, Aomori 034-8628, Japan. hohdatsu@vmas.kitasato-u.ac.jp
authors: Tsutomu
authors: T
authors: Hohdatsu
authors: Ayanori
authors: A
authors: Yamazaki
authors: Mitsunobu
authors: M
authors: Yamada
authors: Hajime
authors: H
authors: Kusuhara
authors: Takashi
authors: T
authors: Kaneshima
authors: Hiroyuki
authors: H
authors: Koyama
mesh_terms: D000818:Animals; D018791:CD4 Lymphocyte Count; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D002371:Cat Diseases / Q000276:immunology / Q000821:virology; D002415:Cats; D016181:Feline Acquired Immunodeficiency Syndrome / Q000276:immunology*; D016089:Immunodeficiency Virus, Feline / Q000276:immunology*; D012367:RNA, Viral / Q000097:blood; D014766:Viremia / Q000276:immunology* / Q000821:virology
chemical_list: D012367:RNA, Viral