**, significant difference
**, significant difference. 4. patients at risk for diseases caused by human polyomaviruses. and beta-herpesvirus lifecycles are unrelated; i.e., polyomaviruses lack a latent-lytic contamination relationship with host cells, and may instead persist in a smoldering continuous infectious state. Whether ongoing contamination is required for maintenance and function of anti-polyomavirus T cell responses is usually unknown. Because no anti-polyomaviral compounds are available to control contamination in vivo, we developed an approach to genetically disrupt the dsDNA viral genome during acute and prolonged phases of contamination. A mutant MuPyV, A2-Flx, was created in which two identically oriented loxP sites were inserted into the MuPyV genome, one in its noncoding region just upstream of the early promoter and the other in the intron region shared by the LT, MT, and ST genes (STIN).…