Antigenicity of tropoelastin

A serum antibody, specific for tropoelastin was developed in rabbits. The tropoelastin antigen was extracted from the aortas of swine raised on a copper-deficient diet. The amino acid composition and molecular weight of the tropoelastin antigen was determined through amino acid analysis and disc electrophoresis. Antibodies to tropoelastin were obtained by immunizing rabbits with tropoelastin. The presence of anti-tropoelastin antisera was determined initially by a screening, serologic ring test and further by immunodiffusion. Serologic tests were employed to determine the specificity and homogeneity of the antibody, after its presence had been established. Electroimmunodiffusion, passive hemagglutination and gel immunodiffusion showed that there was no cross-reactivity with other connective tissue proteins, specifically, glycoprotein and trooocol1agen. Alpha elastin was also tested and showed no cross-reactivity with the developed antibody. The results of these tests suggested the presence of more than one antigen-antibody system present in the antisera. To provide additional information on the antigenic components present in the antigen, tropoelastin was fractionated on a Sephadex G-200 column. Six fractions were collected and checked for antigenic reactivity with the antibody by use of electroimmunodiffusion and immunodiffusion. Five of the six fractions exhibited antigenicity. By use of these tests it was also determined that three antigenic components were present in the starting antigen. All three of these components were found in each fraction with certain fractions being enriched in each antigenic component.