Polyoma tumor development in neonatally polyoma-virus-infected CD4-/- and CD8-/- single knockout and CD4-/-8-/- double knockout mice

Abstract

CD4-/- or CD8-/- single knockout as well as CD4-/-8-/- double knockout mice were infected with polyoma virus as newborns or 1 week after birth. The animals were followed for tumor development and virus persistence. Double knockout mice developed tumors at a higher incidence (29%) than either the CD8-/- or CD4-/- single knockout mice (11% and 2%, respectively). Persistence of polyoma virus was examined by PCR in one third of all animals included in the study. Seven of the 17 CD4-/-8-/- double knockout mice gave positive evidence of virus persistence up to 6 months p.i. where virus DNA was present in most organs. Corresponding tests in single knockout mice gave positive results of persistent viral DNA in 2 of the 19 CD8-/-and 2 of the 7 CD4-/-mice. In the single knockout mice polyoma DNA could only be detected in a more limited variety of organs compared to the double knockouts.