Apoptosis Enhanced by Soluble Factor Produced in Feline Immunodeficiency Virus Infection

Abstract

Feline immunodeficiency virus (FIV)-infected cells have been shown to undergo apoptosis by treatment with tumor necrosis factor alpha (TNF-α). This study detected a soluble factor which enhanced the apoptosis induced by TNF-α treatment. The sensitivity to TNF-α in the induction of apoptosis in a feline fibroblastoid cell line (CRFK) cells was significantly enhanced when the culture supernatant of FIV-infected CRFK cells or plasma samples from FIV-infected cats was added to the culture. These findings suggested that FIV infection induces production of a soluble factor which enhances CRFK cells sensitivity to TNF-α induction of apoptosis both in vitro and in vivo. This factor may contribute to the loss of lymphocytes in cats infected with FIV.