DETECTION AND PARTIAL CHARACTERIZATION OF OCULAR CICATRICIAL PEMPHIGOID ANTIGENS ON COLO AND SCABER TUMOR-CELL LINES

Ocular cicatricial pemphigoid (OCP) is a chronic autoimmune inflammato ry disease which affects the conjunctiva and other squamous epithelial mucous membranes resulting in a scarring process. It is characterized by the deposition of an antibasement membrane zone (BMZ) antibody in vivo, Sera from 11 patients with active OCP were studied. Using monkey esophagus and normal skin as substrate, weak staining of the BMZ was observed in conventional indirect immunofluorescence (IIF) assay. Usin g salt split human skin as substrate, the OCP sera demonstrated bindin g to the epidermal side of the split. in low titers with weak staining . Ten of the 11 sera were positive on an immunoblot assay using COLO a nd SCaBER tumor cell lysates demonstrating 230, 205, 160. and 85 kD pr oteins. Sera from six bullous pemphigoid (BP) patients. with only cuta neous involvement and high titer of anti-BMZ antibody, as detected by IIF, also bound to 230, 160, and 85 kD proteins on both lysates in com igration experiments. Serum from five normal individuals and two patie nts each with severe atopic conjunctival disease. erythema multiforme with chronic conjunctivitis and systemic lupus erythematosus (SLE). di d not demonstrate those bands. When the two lysates were first absorbe d with BP sera and then the same lysates were immunoblotted with OCP s era, in all ten OCP sera the 230, 160. and 85 kD bands were eliminated and only a single 205 kD band was uniformly present. These results in dicate that OCP sera recognize peptide(s) present in 230. 205 and 160 kD proteins in lysates from COLO and SCaBER tumor cells. These protein s contain the immunodominant region of the BMZ molecule(s) in which th e OCP antigen(s) reside. The OCP antigen(s) appears to be distinct fro m the BP antigen(s).