Med. (1989) 169:1747-1756; Dhein et al. (1995) supra; Brunner et al. (1995) supra and Ju et al. (1995) supra) However, this method is particularly suitable for use with TCR+, CD8+ or CD4+ T cells or tissues that harbor the simian immunodeficiency virus (SIV) or alternatively, the human immunodeficiency virus (HIV).