[A two-step method of purifying the surface antigen of the hepatitis B virus and its use in the passive hemagglutination reaction for indicating antibodies to the surface antigen of the hepatitis B virus].

A simple and economic scheme for the purification of HBsAg has been developed: step I--immunosorption with the use of a cellulose suspension with immobilized purified anti-HBs, and step II--isopycnic ultracentrifugation through CsCl. This method yields a 300-fold purified HBsAg, its harvest being 75%. An erythrocytic immunodiagnosticum for the passive hemagglutination test has been prepared on the basis of this purified HBsAg; the sensitivity of the test with this immunodiagnosticum is but slightly inferior to that of radioimmunoassay. The specificity and immunogenicity of the resultant HBsAg preparation has been tested by rabbit immunization. The obtained highly effective sera contained no antibody to human proteins. The results recommend the suggesman proteins. The results recommend the suggested method for wide practice.