Plaque size phenotype as a selectable marker to generate vaccinia virus recombinants

In this report, we provide a new method for selection of vaccinia virus recombinants expressing foreign genes. The method is based on the use of the gene encoding the viral 14,000-molecular-weight envelope protein that rescues the small-plaque-size phenotype of a vaccinia virus variant to large-plaque-size virus. Selection of recombinants is easily obtained after visual inspection of large viral plaques.