Figure 5.

EMCV replication in U9K-AV2 cells. (A) Total RNA was extracted from noninfected U9K-A controls and persistently infected U9K-AV2 cells to detect steady-state EMCV RNA by RT-PCR. To detect positive- and negative-strand EMCV RNA, cDNA synthesis was achieved by priming total RNA with either 5′ or 3′ EMCV PCR primer. RT-PCR detection of 18S RNA was performed on cDNA from random-primed total RNA. (B) A U9K-AV2 culture was maintained for 4 days. Aliquots were taken at indicated times, freeze-thawed three times, and centrifuged, and the supernatants were titered for EMCV. For comparison, a typical viral yield from U9K-A cells newly infected with EMCV at 0.1 TCID₅₀/cell for 24 hr is included. EMCV titers are plotted on a log₁₀ scale.