HSP-derived peptides inducing uveitis and IgG and IgA antibodies

Heat shock protein (HSP) 65 kD-derived peptides, which specifically stimula te T cells from patients with Behcet's disease (BD). are capable of inducin g uveitis in rats. Mycobacterial HSP 65 kD and BD-specific peptides were in jected into Lewis rats and the development of uveitis was monitored clinica lly and histologically, and IgG and IgA antibodies were measured using an e nzyme-linked immunosorbent assay (ELISA). Rats immunized with HSP peptides that developed uveitis showed significantly higher serum IgG antibody level s to peptide 311-326 (P < 0.05) and the corresponding homologous human pept ide 336-351 (P < 0.01) than rats without uveitis. Significant increases in serum IgA antibodies in rats with uveitis were also observed in those immun ized with peptides 111-125, 311-326 and 336-351 (P < 0.05). Rats injected w ith HSP 65 kD showed a rise in IgG antibody levels to peptides 111-125, 154 -172 and 311-326 and to a lesser extent, a rise in IgA antibody level to pe ptide 311-326. BSP showed almost complete inhibition of binding of IgG anti bodies to HSP 65 kD, but peptides 111-125, 154-172, 311-326 and 336-351 sho wed inhibition to a lesser extent in a competitive assay. These results sug gest that increases in IgG and IgA antibody levels to specific peptides wit hin HSP, develop in rats with uveitis. The T and B cell epitopes responsibl e for the development of ocular disease in rats immunized with HSP-derived peptides, appear to be similar or identical to those found in patients; wit h the ocular type of ED. (C) 1998 Academic Press.