FIG. 7.

Reversion of rA2-P176 during in vitro passage at 37°C. (A) Sequence of the P gene in the region of residue 176 from rA2-P176 passaged in Vero cells. The introduced E176G mutation was progressively reverted to E176D starting from passage 3 (P3). Arrows indicate the G-to-A change in the 176 codon. (B) Replication of the E176D revertant at different temperatures. Monolayers of Vero and HEp-2 cells were infected with rA2 P-E176D; overlaid with L15 medium containing 1% methylcellulose and 2% FBS; and incubated at 33, 37, and 39°C.