Toward a detailed characterization of feline immunodeficiency virus-specific T cell immune responses and mediated immune disorders

• Published in: Veterinary immunology and immunopathology 2005-06, Vol.106 (1), p.1-14
• Main Authors: Paillot, R., Richard, S., Bloas, F., Piras, F, Poulet, H., Brunet, S., Andreoni, C., Juillard, V.
• Format: Article
• Language: English
• Subjects: Animals; Antigens, Viral - blood; Apoptosis; Cat Diseases - immunology; Cat Diseases - virology; Cats; CD4-positive T-lymphocytes; CD8-positive T-lymphocytes; cell-mediated immunity; Cellular immune response; cytokines; differential staining; disease course; enzyme-linked immunosorbent assay; feline acquired immunodeficiency syndrome; Feline immunodeficiency virus; Female; FIV; General immune activation; homeostasis; Human immunodeficiency virus; IFNγ; immune response; Immunodeficiency Virus, Feline - immunology; in vitro culture; Interferon-gamma - blood; interferons; Lentivirus Infections - immunology; Lentivirus Infections - veterinary; Lymphocyte Activation; Male; pathogenesis; Specific Pathogen-Free Organisms; T-Lymphocyte Subsets - immunology; T-Lymphocyte Subsets - metabolism; temporal variation; TNFα; tumor necrosis factor-alpha; Tumor Necrosis Factor-alpha - metabolism; viral antigens; Viremia
• ISSN: 0165-2427; 1873-2534
• DOI: 10.1016/j.vetimm.2004.12.023

Infection of domestic cats with feline immunodeficiency virus (FIV) is associated with the development of an acquired immunodeficiency syndrome (AIDS). The pathogenesis of FIV is not fully understood but it has been reported that the immune system is progressively impaired during disease progression. As a result, anti-FIV specific immune response will usually not clear the virus and the acute stage is followed by a chronic asymptomatic phase. The overall objective of this study was to characterized FIV-induced immune cellular responses and -mediated immune disorder following the first weeks post-infection. Using both cytokine ELISpot and intracellular staining assays, FIV-specific T cells were monitored at 6, 9 and 12 weeks post-infection. We demonstrated that both IFNγ + and, CD4 and CD8 TNFα + T cells specifically respond to FIV antigens. These responses were found to reach a peak at 9 weeks post-infection. It was further shown that the TNFα +CD8 + responding T cells were contained within a CD8β lowCD62L − T cell subpopulation, expanded in FIV-infected cats. This T cell subpopulation which present features of activated CD8 T cells was further shown to be susceptible to spontaneous apoptosis following a short-term in vitro culture. Moreover, it was observed that cell death by apoptosis of this T cell subset was increased following FIV antigen-recognition. Therefore, FIV might alter immune homeostasis in inducing chronic activation of TNFα +CD8 + T cells which eventually will die following antigen contact while deleting CD4 + T cells. Interestingly, this study confirmed the strong similarity between FIV and HIV pathogenesis.