The persistence of papovavirus BK DNA sequences in normal human renal tissue

Oncogenity of BK virus for immunosuppressed hamsters

Tumors were induced by BK virus (BKV) inoculated intravenously in 3-week-old Syrian golden hamsters immunosuppressed with anti-lymphocyte serum or methylprednisolone acetate alone or in association with gamma-radiation (60Co). The induced neoplasms were ependymoma, carcinoma of pancreatic islets, lymphoma, osteosarcoma, undifferentiated sarcoma, kidney and renal pelvis carcinoma, pheochromocytoma and hemangiosarcoma. High levels of insulin and glucagon and altered concentrations of glucose were detected in blood of animals with tumors of pancreatic islets. No antibodies to BKV tumor antigen (TAg) and low levels of hemagglutination-inhibition antibodies to BKV viral coat protein Ag were detected in hamster sera. BKV TAg was found in tumors by complement fixation. Blot hybridization analysis of tumor DNA showed the presence of both free and integrated BKV genomes in tumor cells. BKV DNA inoculated intravenously and subcutaneously in immunosuppressed or immunocompetent hamsters was not oncogenic, whereas it was weakly oncogenic when inoculated intracerebrally.

The role of BK virus in acute respiratory tract disease and the presence of BKV DNA in tonsils

The significance of BKV infections relative to infections by generally tested respiratory agents was investigated in children with acute respiratory disease. Paired sera from 177 children admitted to a hospital for acute respiratory disease were tested for significant rises in antibodies. Sera from seven patients showed a seroconversion to BKV and clinical signs of acute upper respiratory tract infection were exhibited by each of these patients. BKV infections were present in 8% of the patients with upper respiratory tract disease while seroconversions to adenovirus (2%), influenza A virus (1%), parainfluenza virus (5%), RS virus (6%) and mycoplasma pneumoniae (1%) were observed in 15% of the patients with upper respiratory tract disease. BKV was isolated from the urine of one child with tonsillitis with a concomitant seroconversion to BKV. Tonsils from children with recurrent attacks of acute respiratory disease were tested for the presence of BKV DNA by hybridization with a cloned genomic 32P-labeled DNA of prototype BKV. Five of twelve tonsil DNAs showed hybridization with BKV DNA. Each tonsil showing hybridization with BKV DNA contained multiple nonintegrated copies of the BKV genome per diploid amount of host cell DNA. Attempts to recover infective BKV by transfection of primary human embryonic cells with tonsil DNAs or by co-cultivation of tonsillar cells with primary human embryonic cells were unsuccessful.