title: Filtration and immunoprecipitation in the elimination of DNA polymerase activity associated with bacterial contamination of sera positive for hepatitis B e antigen and its corresponding antibody.
abstract: Samples of serum inoculated with Escherichia coli and serum that became contaminated with bacteria after exposure to a laboratory atmosphere demonstrated elevated DNA polymerase activity. The levels of activity were well within the range of values found in hepatitis B e antigen (HBeAg)-positive samples. The bacterial polymerase activity was markedly reduced by a single passage of serum samples through a 0.22-micron Millipore filter prior to analysis. Repeated filtration did not result in a substantial further decrease in polymerase activity. In sera that were heavily contamined with E. coli, however, filtration was not successful in reducing bacteria-associated polymerase activity to a base-line uncontaminated level. In such instances double antibody immunoprecipitation proved effective in elimination of bacterial activity. When bacterial contamination of serum samples is a possibility, specimens should be subjected to either Millipore filtration or immunoprecipitation prior to analysis, particularly when correlation of DNA polymerase activity with HBeAg and its corresponding antibody is attempted.
mesh_terms: D000914:Antibodies, Viral; D011232:Chemical Precipitation; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism*; D004926:Escherichia coli; D005374:Filtration; D006510:Hepatitis B Antibodies; D006511:Hepatitis B Antigens; D006801:Humans; D013210:Staphylococcus; D013997:Time Factors
chemical_list: D000914:Antibodies, Viral; D006510:Hepatitis B Antibodies; D006511:Hepatitis B Antigens; D004259:DNA-Directed DNA Polymerase