IMMUNOLOCALIZATION OF INTEGRINS IN THE HUMAN RETINA

Purpose. Integrins are cell surface proteins that participate in inter actions between cells and with extracellular matrix. Binding of integr ins to their ligands influences cell activities including proliferatio n, migration, and differentiation. Expression of integrin subunits fro m three different subfamilies was examined in human retina. Methods. I ntegrins were detected in frozen sections of two human retinas with an avidin-biotin-complex immunohistochemical technique, using nine diffe rent monoclonal antibodies specific for alpha(2), alpha(3), alpha(4), alpha(5), alpha(6), alpha(v), beta(1), beta(2), and beta(3). One retin a was from a patient who had conjunctival squamous cell carcinoma, and the other was from uninvolved regions of an eye with a choroidal mela noma. Results. All integrins tested were detectable in consistent patt erns in two retinas. All except alpha(2) and alpha(4) were stained vib rantly in retinal and choroidal vessels. All alpha subunit staining of vessels showed overlap or close proximity to beta(1) staining. In add ition to vessels, beta(1) was also present in the internal limiting me mbrane; alpha(2), alpha(3), alpha(4), alpha(5), and beta(2) were all f ound throughout much of the neural retina, albeit with distinctive sta ining patterns. Other than in association with vessels, alpha(6) and a lpha(v), were not detected in neural retina, and pg was only weakly de tected in the nerve fiber layer; alpha(4) and beta(2) were expressed i n the retinal pigment epithelium; beta(1) and Pe were strongly express ed in drusen present in one of the eyes. Conclusion. Nine integrin sub units have been found to have unique distributions in adult human reti na. An understanding of the distribution in normal retina can serve as a useful contrast to patterns of staining associated with retinal dis eases,