Strain differences and some serological observations on several isolates of human polyomaviruses

Six new strains of BK polyomavirus are described and compared by serological reactions and restriction endonuclease digest patterns of their DNA to BKV (prototype) and BKV (GS). One strain (PG) had a restriction endonuclease pattern similar to BKV (prototype) but with two EcoRI cleavage sites. Four strains were similar to BKV (GS) and one strain (SB) appeared to be a variant of BKV, having a smaller defective genome. Two mixed polyomavirus infections have been identified and a new human polyomavirus (ASV), distinct from BKV and JCV, has been described.