Abstract
Summary
The presence of DNA polymerase in normal human serum and its possible association with Australia antigen was investigated. DNA polymerase activity was determined in 135 samples of normal serum. Only 3 samples revealed appreciable amounts of activity. The addition of a variety of polynucleotide templates did not stimulate polymerase activity.
Australia antigen is a particle associated with hepatitis and is reported to contain RNA. A DNA polymerase, “reverse transcriptase” might be required for replication of this RNA. We found DNA polymerase activity in only one of five preparations of purified Australia antigen. A similar activity was also found to be present in serum from certain normal volunteers. In either case, polymerase activity does not require nor is it stimulated by added polynucleotides suggesting that the enzyme may already be associated with a template such as RNA or DNA. A comparison between the amount of DNA polymerase activity in serum and the presence of Australia antigen in three series of patients with Down's syndrome and hepatitis revealed at most a marginal positive association. Thus, DNA polymerase is probably not a part of Australia antigen and the association observed is probably of an indirect nature. Its presence in occasional normal sera must be considered when using this activity as an index for detection of oncogenic viruses.
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