FIG. 2.

Infectious virus is isolated after coculture of activated PBMC from the NIH miniature pig or the Yucatan with ST-IOWA cells. PBMC isolated from the NIH miniature pig or Yucatan pig were cultured with PHA and PMA for 5 days prior to coculture with ST-IOWA cells. Cell culture medium was removed at each of the days indicated and assayed for reverse transcriptase activity. The values for counts per minute of [³H]TTP incorporated for cells exposed to NIH miniature pig PBMC are shown by solid black squares, and those for cells exposed to Yucatan pig PBMC are shown by open circles. Background values for uninfected ST-IOWA cells have been subtracted from the values shown. cpm, counts per minute.