Immunologic localization of elastin by electron microscopy.

Research on the pathogenesis of experimental emphysema has involved studies of the distribution of and destruction of elastin in the alveolar interstitium. The ill-defined organization of elastin in the alveolar interstitium makes it difficult to identify the elastin specifically by staining procedures ordinarily used for electron microscopy. This problem becomes more significant when the elastic tissue is fragmented during emphysema development and localization of the elastin fragments is essential. Therefore, a specific technique using high-titer antibodies against purified canine lung elastin was developed. The primary antibody was used on preembedded or etched postembedded sections. Localization of the antielastin IgG was accomplished with ferritin-labeled rabbit antisheep IgG as the secondary antibody. Treatment with the preimmune serum gave negligible ferritin background staining. The antielastin antibody did not react with lung connective tissue proteins such as the microfibrillar component of elastin or collagen or proteoglycan. The antielastin antibody appeared to be species specific. The method may be useful for studies of experimental emphysema.