A modified plaque assay and infected cell hybridization assay for wild-type and recombinant LuIII autonomous parvovirus.

We describe a convenient infected cell hybridization assay for determining the infectious titer of a recombinant, replication-defective parvorirus. We previously generated recombinant derivatives of the autonomous parvorirus LuIII, transducing the luciferase reporter gene. Since luciferase expression is not readily detected at the single cell level, and since the recombinants cannot form plaques, we developed an alternative assay for infectious particles. Co-infection of NB324K cells with wild-type LuIII (multiplicity of infection ca. 5) and the recombinant virions allows amplification of the transducing DNA, which can be detected by hybridization with a probe for the reporter gene