Immunohistochemical comparison of ocular zonules and the microfibrils of elastic tissue

Antibody to bovine zonules raised in rabbits gave diffuse staining of zonular fibrils with prominent accumulations at 35 to 45 nm sites of overbanding by means of the indirect immunoperoxidase technique. Antibody binding occurred in both fresh and paraffin-embedded material and was not species specific. The same pattern of heavy antibody binding and 35 to 45 nm periodicity was found on the microfibrils of elastic tissue in human and bovine ciliary body, calf ligamentum nuchae, and chick aorta. This cross reaction is the first direct evidence of a structural similarity or identity between components of the zonules and the microfibrils of elastic tissue, correlating with similarities in their morphology and amino acid profiles. Interstitial collagen fibers appear to have a minimal quantity of antigenically similar material at cross-banding sites. These relationships may hold important clues to the site of systemic involvement in connective tissue diseases associated with lens dislocation. Zonular antibody should prove useful in investigating abnormalities of the zonular-elastic microfibrillar system and cross-banding sites.