Antigenic determinants of human beta-1c and beta-1g-globulins.

Abstract

Summary Four distinct antigenic determinant groups have been found to be associated with β 1C -globulin. Antigen A is present on β 1A and antigen D is on a second breakdown product of β 1C , designated α 2D . Both are also present on β 1C . Another antigen is also present on α 2D which has been designated D d but this is not present on β 1C . A fourth antigen of β 1C , designated B, is completely lost from the serum as β 1C breaks down with aging. Antiserum containing antibody only to this group forms a β 1C are with fresh serum but does not react with aged serum. α 2D loses most of its antigenicity on heating serum for 1 hr at 56°. β 1A is unaffected by this treatment. The breakdown of β 1C occurring on reaction of fresh serum with zymosan or immune precipitates resembles in all respects that occurring with aging. Hydrazine or ammonia treatment, however, diminishes the mobility of α 2D . β 1G , produced by reaction of isolated β 1C with EAC′ 1,4,2a cells, has A, D and D d antigens but lacks the B antigen. Its mobility is similar to that of β 1A . The studies suggest that β 1C undergoes marked unfolding and configurational changes as it breaks down. A close relationship may be assumed between the B antigen of β 1C and the activity of the molecule in immune hemolytic reactions.