[Binding of the surface antigen of the hepatitis B virus with antibodies studied with different denaturation...

The effect of delipidizing agents and a reducing agent on the antigenicity of 20 nm particles of hepatitis B virus surface antigen (HBsAg) was studied. The antigenicity was determined from the capacity of binding with antibody in passive hemagglutination test (PHAT) and dot-blot immune binding (DBIB). Delipidation was found to lead to an apparent decrease of antigenicity caused by aggregation. Subsequent destruction of the aggregates by treatment with sodium dodecylsulphate (SDS) reduced the antigenicity. Treatment with the reducing agent in the presence of SDS results in the loss of antigenicity detectable by PHAT, the DBIB titres remaining unchanged. Some examples demonstrate a high sensitivity of DBIB in detection of HBsAg. The advantages of the latter test over other methods of immune diagnosis are discussed.