GENERATION OF COMPLEMENT MEMBRANE ATTACK COMPLEX IN NORMAL HUMAN CORNEAS

Purpose. To determine whether complement-derived SC5b-9, the soluble n onlytic-fluid phase of the membrane attack complex, can be generated i n normal human corneas when they are injured with lipopolysaccharide ( LPS), ribitol teichoic acid (RTA) immune complexes, acid, or alkali. M ethods. The experimental cornea of each donor pair was injected with 5 0 mu l of sterile saline containing 0.5 mg of LPS or 50 mu l of steril e saline containing 250 mu g of RTA immune complexes. Other experiment al corneas were treated topically for 35 seconds with either 200 mu l of 1N HCl or 2N NaOH. The control cornea of each donor pair was inject ed with 50 mu l of sterile saline or was treated topically for 35 seco nds with 200 mu l of sterile saline. After injury, all corneas were in cubated in medium 199 for 6 hours at 37 degrees C in 5% CO2, then elut ed for 24 hours in phosphate-buffered saline with 10 mM ethylenediamin etetraacetic acid. Each corneal eluate was collected and stored at -70 degrees C until assayed for SC5b-9 by an enzyme immunoassay. Results. Compared with control corneas, SC5b-9 levels were increased significa ntly in corneas injected with LPS or RTA immune complexes. However, wh en compared with controls, SC5b-9 levels were decreased significantly in corneas treated with HCl or NaOH. Conclusions. Normal human corneas injured immunologically with LPS or RTA immune complexes activate the classical or alternate pathway and generate SC5b-9. Corneas injured c hemically with acid or alkali do not produce SC5b-9.