The Relative Heat Stability of Antibodies in Chromatographic Fractions of Rabbit Antisera to Various Antigens

Abstract

Chromatographic fractions containing, on the one hand, predominantly 7 S, mercaptoethanolresistant antibody and on the other, 19 S, mercaptoethanol-sensitive antibody were prepared from rabbit antisera to the H and O antigens of Salmonella typhosa, Leptospira grippotyphosa, bovine serum albumin, and sheep erythrocytes. Agglutinins in the 7 S fractions were found to be more resistant to inactivation by heat than the agglutinins in the 19 S fractions. A similar difference in resistance to heat was demonstrated for the hemolytic activity of 7 S and 19 S antibodies to sheep erythrocytes and to the somatic antigens of S. typhosa. The observed differences in heat inactivation could not be accounted for by the formation of complexes between antibody and other serum proteins as a result of heating. The relative heat resistance of 7 S antibody as compared to 19 S appears to explain the well known difference in the susceptibility of somatic and flagellar agglutinins to inactivation by heat.