Abstract
Oda (1965) reported the rescue of dermovaccinia (strain Dairen I) abortive infection by neurovaccinia virus (strain IHD-T) in mouse fibroblastic L cells. The present study, however, provided no evidence for such, but gave evidence for the occurrence of genetic recombination between the viruses in L and HeLa cells. HeLa and L cells were infected simultaneously with strain Dairen I which produces hemagglutinin (H+) and replicates well in HeLa cells but only poorly in L cells, and strain IHD-T which is H- and multiplies well in both cells. Sixty-eight of 225 and 24 of 114 clone preparations from the mixed infection yields in L and HeLa cells, respectively, were mixtures of H+ and H- viruses. The remaining 157 and 90 clones contained only one type of virus, H+ or H-, and varied widely in the plaquing efficiency for L cells. This contrasted with the results from parent viruses. An interpretation is that the plaquing efficiency is controlled by multiple genes and genetic recombination between the two vaccinia viruses with differing plaquing efficiencies results in occurrence of recombinants demonstrating u variety of plaquing efficiency. Hemagglutinin production was an all-or-none character, no intermediates being found, and can readily be tested at the particle level by the plaque-hemadsorption technique. These points render hemagglutinin production as u suitable marker for the genetic studies in contrast to the polygenic plaquing efficiency.
