Virus replication from tonsil derived cells. Tonsil cells isolated by 1) pressing the tissue over a sieve and by Ficoll-hypaque density-gradient centrifugation, 2) pressing the tissue over a sieve but without Ficoll-hypaque density-gradient centrifugation, 3) mechanically disaggregated tonsil tissue without any further separation, namely, minced tonsil tissue cells. Two to three million cells were infected with serial dilutions of cell free HIV-1BAL at 1:4, 1:16, 1:64, starting TCID50 of 106.