Characterization of human papovavirus RFV: comparison with SV40 and BKV

Human papovavirus, RFV, isolated from urine of a renal transplant patient was compared with two strains of SV40 and with the prototype human papovavirus, BKV. Neutralization tests showed that RFV and BKV are indistinguishable, while large-plaque (LP) and small-plaque(SP) isolates of SV40 gave a low but significant level of cross-reaction with rabbit or human antisera against RFV. DNA reassociation saturation tests using 125I-labelled RFV DNA show that BKV has 88% homology, and SP-SV40 has 29% homology to RFV. We conclude that RFV and BKV are nearly, if not totally, identical and are not SV40 variants.