Glycoproteins of natural origin with an affinity for hepatitis B surface antigen.

Sera from certain animal species contain a substance(s) which binds hepatitis B surface antigen. The hepatitis B binding substance found in animals is not antibody, but appears to be a glycoprotein which reacted with antigen-coated beads and produced a "false positive" test for antibody. This glycoprotein could be selectively and quantitatively removed by reaction with purified hepatitis B surface antigen and centrifugation. Pili fractions isolated from Neisseria gonorrhoeae and Escherichia coli bound to hepatitis B surface antigen and produced false positive anti-hepatitis B surface antigen reactions. Mouse anti-bovine hepatitis B binding substance and rabbit anti-E. coli pili were capable of neutralizing bovine hepatitis B binding substance.