title: Lymphocyte population changes in cats naturally infected with feline immunodeficiency virus.
abstract: Feline immunodeficiency virus (FIV) is associated with feline acquired immunodeficiency syndrome (FAIDS) and has been suggested as a model for HIV-induced human AIDS. The most obvious immunological defect in HIV infection is a reduction in CD4+ cell numbers and an inversion of the CD4:CD8 ratio. To determine whether the same is true in FIV infection, we analyzed by flow cytometry using a panel of monoclonal antibodies to feline lymphocyte populations the CD4:CD8 ratios in cats naturally infected with the virus. We report that 13 of 19 FIV-infected cats had ratios below the 5th percentile of normal cats (0.57, established from analysis of 39 normal cats) and 18 of 19 had ratios below 1. Repeated analyses over a period of several months revealed the inverted ratios to be consistent. Analysis of lymphocyte numbers in FIV-infected cats shows that the inverted ratios are due to a decrease in CD4+ T cells, while CD8+ T and B cells remain relatively normal in number. Analysis of a group of cats with a variety of other chronic diseases, including feline leukemia virus (FeLV) infections, revealed a near-normal distribution of CD4:CD8 ratios. These findings are similar to those in HIV infections and indicate that, like HIV, FIV causes a selective reduction in CD4+ cells and should be an excellent model for studying retrovirus-induced AIDS.
authors.affiliation: Department of Companion Animal and Special Species Medicine, College of Veterinary Medicine, North Carolina State University, Raleigh 27606.
authors.forename: C
authors.initials: C
authors.lastname: Novotney
authors.forename: R V
authors.initials: RV
authors.lastname: English
authors.forename: J
authors.initials: J
authors.lastname: Housman
authors.forename: M G
authors.initials: MG
authors.lastname: Davidson
authors.forename: M P
authors.initials: MP
authors.lastname: Nasisse
authors.forename: C R
authors.initials: CR
authors.lastname: Jeng
authors.forename: W C
authors.initials: WC
authors.lastname: Davis
authors.forename: M B
authors.initials: MB
authors.lastname: Tompkins
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral / Q000097:blood; D001402:B-Lymphocytes / Q000276:immunology; D015153:Blotting, Western; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D002415:Cats; D016181:Feline Acquired Immunodeficiency Syndrome / Q000276:immunology*; D005260:Female; D005434:Flow Cytometry; D016089:Immunodeficiency Virus, Feline / Q000276:immunology; D007958:Leukocyte Count; D008297:Male; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral