The effect of colonizing mice with laboratory and wild type strains of E. coli containing tumor virus genomes

Conventional, antibiotic-compromised, and germ-free mice were either fed or subcutaneously inoculated with laboratory or wild type strains of E. coli containing monomeric or dimeric forms of polyoma (PY) virus DNA. Mice were bled at 3 and 6 weeks following administration of E. coli and their sera examined for the presence of PY hemagglutination inhibiting antibodies. None of the mice developed PY infection; despite colonization of the intestinal tract accompanied by prolonged excretion of high titers (10(9) colony-forming units/gram feces) of E. coli harboring potentially infectious PY virus DNA, no evidence of infection could be demonstrated.