Immunological Studies with Human Aortic Elastin

Abstract

Antibodies to human fetal aortic elastin were isolated from sheep immunized with α-elastin peptides. In preliminary tests of specificity using passive hemagglutination, partial cross-reactivity was demonstrated with α-elastin from other species. However, in a double antibody radio-immunoassay α-elastin peptides from other mammalian species failed to compete with ¹²⁵I-labelled human alpha elastin.

These results suggest the existence of at least two different antigenic sites on the elastin molecule. One, a high affinity site, demonstrates species specificity at low antigen/antibody concentrations. The other, a low affinity site, is common to mammalian elastins and is demonstrated at high antibody/antigen concentrations.

In the radioimmunoassay the antibodies showed considerably less avidity for adult human α-elastin than for the fetal antigen. This implies that the species specific site is age-dependent and probably involves the cross-linking region of the elastin molecule.

Using the sheep antiserum immunohistochemical staining of elastic tissue has been developed. This should prove to be a useful technique for studying polymeric elastin in intact tissue by light microscopy and at the ultrastructural level.