Cold-adapted recombinants of influenza a virus in MDCK cells I. Development and characterization of A/Ann Arbor/6/60 × A/Alaska /6/77 recombinant viruses

摘要: Abstract Recombinant influenza viruses made at 25 and 33° in Madin-Darby canine kidney (MDCK) cells using the cold-adapted A/Ann Arbor/6/60 virus wild-type A/Alaska/6/77 were biologically genetically analyzed. Eight recombinants separated into two phenotypic groups based on (ca) temperature-sensitive (ts) markers: ca ts, non-ts. The showed different degrees of cold adaptibility (DOCA) patterns growth 25°. All contained most three genes from variant (triple-gene recombinant) or one gene parent (double-gene single-gene recombinants, respectively). Further, same genes, RNA2, RNA3, RNA5 (NA) only found various recombinants. Two clones all both (ts). other recombinant non-ts, RNA2 and/or (NA). Each set correlated with a different, but specific characteristic exhibited by their curves Single-gene containing rapid early infection intermediate final yield (between titer for virus; while slow infection, high (equivalent to that parent). double-gene these yield. Thus, adaptation can be transferred least independent each which confer cold-adaptive property its own pathway. genetic basis temperature sensitivity involves remains ambiguous absence RNA3 variant.