Modulation of host cell activation during feline immunodeficiency virus (FIV) infection

The authors describe the mitogenic effect of feline immunodeficiency virus (FIV) infection (1) in vitro, on feline resting peripheral blood lymphocytes (PBL), and (2) in vivo, in experimentally infected cats. Infected PBL were more readily recruited than non-infected PBL, into the G1 phase of the cell cycle and showed increased expression of the specific cell-cycle markers p53 and p56. In-vivo lymphocyte activation following FIV infection was demonstrated by increased germinal centre activity in infected lymph nodes, together with a high expression of CD30, a B-cell activation marker. These results suggest that early events in FIV infection include modulation of host cell activation. Possible implications for pathogenesis are discussed.