Serum antibody response to human and bovine IRBP in uveitis

Abstract

Interphotoreceptor retinoid binding protein (IRBP) is a 136,000 molecular weight photoreceptor cell protein capable of inducing an experimental autoimmune uveitis (EAU) in susceptible animal strains. The occurrence of serum antibodies against human (Hu) or bovine (Bo) IRBP was investigated in patients with uveitis and healthy controls. A sensitive ELISA detected anti-IRBP in approximately 50% of patients and controls, without apparent differences in the mean level, titre or avidity and irrespective of the origin of the antigen. Although the correlation (p less than 0.001) between anti-HuIRBP and anti-BoIRBP levels in uveitis sera suggested the presence of crossreacting antibodies, these sera also contained antibodies specific for either the human or the bovine antigen. The only difference between patients and controls was the greater ability of antibodies in uveitis sera (p less than 0.05) to recognize a synthetic peptide of HuIRBP, which induces severe EAU in rats. We conclude that autoantibodies to IRBP occur naturally in man and are not increased in patients with uveitis.

Aqueous Humor and Serum Immunoblotting for Immunoglobulin Types G, A, M, and E in Cases of Human Ocular Toxoplasmosis

“…By quantitative ELISA, specific antibodies of the IgA, IgM, and IgE types have been demonstrated to occur in ocular toxoplasmosis patients at the following frequencies: IgA, from 26% (6) through 52% (30) to 63% (17) in the aqueous humor; IgM, from Ͻ1% (6, 30) to 11% (17) in the aqueous humor and to 50% in the serum (21,25); IgE, from 0% (18) to 14% (7) in the vitreal fluid and to 66% in the serum (21,27). The levels of IgE within the aqueous humor have not been determined, which is surprising given the purported role of this class of immunoglobulin in ocular toxoplasmosis-related hypersensitivity (24,37) and autoimmunity (11,14,22,35,36). The broad range of sensitivities reported for the different types of specific antibodies probably reflects the usually small number of patients included and the case selection criteria employed, e.g., the mode a Includes determination of levels of total and specific IgG, specific IgA, and specific IgM in the aqueous humor and serum, amplification of parasite DNA in the aqueous humor by PCR, and immunoblotting for anti-Toxoplasma IgG and IgA.…”

Proliferative Vitreoretinopathy May Be a Risk Factor in Combined Macular Hole Retinal Detachment Cases

“…The only difference has been the stronger affinity of the antibodies in patients with uveitis. 92 The relationship between humoral and cellular response to these autoantigens was studied in a group of patients with endogenous uveitis such as birdshot retinochoroidopathy, retinal vasculitis, and Behçet disease. The antibody titers to S-antigen and IRBP were found to be decreased during active inflammation periods and the lymphocyte responses to S-antigen were found to be most significant in the period preceding a relapse of ocular inflammation, supporting the pathogenic roles of these lymphocytes in retinal autoimmunity.…”

Determinants of immunodiagnostic success in human ocular toxoplasmosis

“…However, the antibody levels thereby produced are insufficient to yield evidence of permanent parasite‐induced autoreactivity (94,95). The process is not directed solely against retinal S‐antigen (96,97) as, at least on a cellular level, there is evidence of autoimmune reactions to different retinal antigens during the inflammatory response (98,99).…”