Characterization of a new polyomavirus (Polyomavirus papionis-2) isolated from baboon kidney cell cultures

Viruses with papovavirus morphology were seen in fluids from baboon kidney cell cultures on three separate occasions (isolates A, B, and C). The size of the virions, 47.9 nm, placed the virus in the polyomavirus genus. It grew well in baboon kidney and Vero cells and less well in human embryo lung (HEL) fibroblasts. The virus could not be identified as the previously described baboon polyomavirus, SA 12, or as any of the other known primate polyomaviruses BK, JC or SV 40, the non-primate viruses mouse polyoma, K, rabbit kidney vacuolating virus (RKV) or bovine polyomavirus (FRKV) by immunofluorescence, immune electron microscopy or hemagglutination inhibition (HI) tests. A rabbit antiserum to the new virus (isolate A) reacted only with the three isolates and not with the other primate polyomaviruses studied. Thirteen percent of 118 wild-caught baboons (Papio anubis) had HI antibody to the new polyomavirus and 21 percent were seropositive for SA 12; only two baboons had antibody to both viruses. These results suggest that in baboons there are two antigenically distinct polyomaviruses which circulate independently. The two viruses may also be distinguished by their hemagglutinating properties: SA 12 agglutinated erythrocytes from a wider range of species but only the newly recognized polyomavirus agglutinated baboon erythrocytes. We propose that the two baboon viruses, SA 12 and the new virus, should be named Polyomavirus papionis-1 and Polyomavirus papionis-2 respectively.