Direct detection of apoptotic cells in peripheral blood from highly pathogenic SHIV-inoculated monkey

Apoptosis in peripheral blood leukocytes (PBL) has been estimated by the en hancement of spontaneous apoptosis after in vitro culture, because apoptoti c cells have not been observed directly in freshly isolated PBL in the cour se of HIV/AIDS. In monkeys infected with a highly pathogenic simian/human i mmunodeficiency virus (SHIV), which corresponds to rapid progressors of HN infection, a high frequency of apoptotic cells was directly detected in fre sh PEL by electron-microscopic studies. Peripheral blood apoptosis transien tly occurred after intense plasma viremia, and peaking at 3 weeks postinfec tion; occurrence was not limited specifically to lymphocytes, but also occu rred in other types of leukocytes, Apoptosis in peripheral lymph nodes was also detected following intense plasma viremia. However, the in vivo apopto sis was not detected in nonpathogenic SHIV-infected monkeys that showed no cell loss. Thus, we directly showed the apoptosis of PBL, which might be as sociated with pathogenic SHIV produced during the time of plasma viremia. ( C) 2000 Academic Press.