Interference by specific FMDV mutant combinations.

aInterference was determined by measuring infectious progeny production after co-electroporation of pMT28 RNA alone (first row) or with mixtures of mutant FMDV RNAs (either Q2027A+MD or DMD+D3) in the absence (−) or presence (+) of guanidinium (GU) or ribavirin (R), as indicated. The origin of FMDV mutant RNAs and experimental procedures are detailed in Materials and Methods. bInterference (%) is defined as [titer pMT28–titer pMT28 (plus indicated components)/titer pMT28]×100. Values are the average of three determinations, at 3 h, 5 h and 6 h post-electroporation. Virus titers (expressed as percentage of the titer obtained for pMT28 alone) and standard deviations are given in Figure 3. cNA, not applicable; ND, not detectable.