Expression of Uveitogenic Retinal Antigens in Human Thymi: Variability among Antigens and Individual Thymi

Abstract

Abstract: : Purpose: We have previously reported a correlation between expression of uveitogenic retinal antigens in thymus and resistance to experimental autoimmune uveoretinitis induced by these antigens in mice and rats. (Egwuagu CE et al. J Immunol 1997, 159: 3109). The present study was designed to investigate the expression of uveitogenic retinal antigens in human thymi. Methods: Thymus samples were collected from seven patients during surgery for congenital heart disease, after informed consent was obtained. Total RNA was extracted from these samples and RT-PCR (40 cycles) was performed with primers of four human retinal antigens (see Table). ß-actin was used for normalization. The intensity of the blot bands was used to estimate the levels of transcripts, using an arbitrary scale of 0-3+. Results: Expression of transcripts of the four antigens, by the seven tested thymic samples are shown in the Table: Conclusions: Human thymi express mRNA transcripts of several uveitogenic retinal antigens, with a remarkable variability among both the individual thymi and the tested antigens. It is assumed that the corresponding proteins are translated and central immunotolerance against these antigens is induced, with a potential effect on the resistance/susceptibility of these individuals to specific pathogenic autoimmunity initiated by the retinal antigens.  

Keywords: immune tolerance/privilege • autoimmune disease