FIG. 1.

Porcine PBMC cultured with two combinations of mitogens release reverse transcriptase activity. Cell culture medium was removed at each of the days indicated after porcine PBMC were exposed to either PHA and PMA (black bars) or PMA and calcium ionophore A23187 (grey bars), as described in Materials and Methods. The culture medium was precleared of cell and cellular debris and then assayed for reverse transcriptase activity. The mean values ± standard deviations of the mean for counts per minute (cpm) of [³H]TTP incorporated are shown on the y axis.