SPONTANEOUS PROGRAMMED CELL-DEATH (PCD) PROCESS OF LYMPHOCYTES OF FIV-INFECTED CATS - CELLULAR TARGETS AND MODULATION

Unstimulated lymphocytes from FIV-infected cats undergo spontaneous ap optosis in vitro as indicated by internucleosomal DNA fragmentation an d hypodiploid DNA content of nuclei. Unlike what is reported in HIV-in fected individuals, we observed that cell death of cat lymphocytes was inhibited by activation. Spontaneous apoptosis was reduced by the add ition of cat serum and after activation by phorbol ester (PMA), supera ntigens (SEE, SEA), and to a lesser extent by mitogens such as concana valin A and pokeweed mitogen. In contrast, apoptosis of lymphocytes fr om FIV-infected, but not from control cats was increased in the presen ce of calcium ionophore (ionomycin). Analysis of the phenotype of cell s undergoing apoptosis revealed that cell death is not restricted to a cell subpopulation but involved all lymphocyte subsets. These data su ggest that the mature lymphocytes of FIV-infected cats appear programm ed to die by apoptosis unless rescued by specific agents, such as prot ein kinase C activators or mitogens. (C) 1997 Elsevier Science B.V.