Susceptibility of HSC-F, a cynomolgus macaque cell line immortalized by Herpesvirus saimiri, to infection with various primate immunodeficiency viruses were monitored. While NL432 clone of human immunodeficiency virus type 1 (HIV-1) did not grow at all in HSC-F cells, GH123 and GL-AN clones of HIV-2, and MA239 clone of simian immunodeficiency virus isolated from macaque monkeys (SIVMAC) did grow in these cells. In addition, NM-3 clone of a chimeric simian and human immunodeficiency virus (SHIV) grew fairly well in HSC-F cells. Mutational analyses of accessory genes of GL-AN were successfully performed in the HSC-F cells. These results have thus demonstrated the importance of this cell line for molecular biological studies on HIV/SIV.