Disease relevance of SAG

• These results indicate that the retinal pigment epithelium may play a role in the initiation and perpetuation of uveitis after sensitization with S antigen [1].
• The experimental autoimmune disease elicited by a large dose of retinal S antigen in guinea pigs is characterized by massive necrotizing uveitis and retinitis [2].
• Rabbits injected with retina extract or S antigen developed posterior uveitis [3].
• Assay of S-antigen immunoreactivity in mammalian retinas in relation to age, ocular dimension and retinal degeneration [4].

High impact information on SAG

• Reproducible survival of adult pig rod and cone photoreceptors was obtained for approximately 2 weeks in vitro, with the continued expression of rod opsin, recoverin, S-antigen, cone arrestin, and neuron-specific enolase [5].
• To determine the role of retinal pigment epithelium in the induction of S-antigen-induced uveitis by administration of sodium iodate (NaIO3) to selectively damage the retinal pigment epithelium [1].
• S-antigen in the developing retina and pineal gland: a monoclonal antibody study [6].
• The recombinant virus replicated in cultures of the swine testicle ST cell line and directed the synthesis of S antigen with a maximum yield of approximately 26 micrograms per 10(6) cells [7].
• Porcine S-antigen: cDNA sequence and expression in retina, ciliary epithelium and iris [8].

Chemical compound and disease context of SAG

• Retina S antigen-induced uveitis. The efficacy of cyclosporine and corticosteroids in treatment [9].
• Phospholipase A2, leukotriene C4 and prostaglandin E2 levels in aqueous humour of guinea pigs with experimental S-antigen induced autoimmune uveitis [10].

Biological context of SAG

• Sequence analysis of the expected 611 base pairs in the 5' region and 672 base pairs in the 3' region of DNA fragments indicated that an identical mRNA for S-antigen was expressed in the anterior tissues examined [8].
• Following immunization with the whole protein, these monkeys were capable, however, of developing cellular immunity against S antigen and one of them developed disease [11].
• S antigens isolated from bovine, human, swine and guinea pig retinas had a high pathogenicity in Lewis rats, whereas allogenic S antigen did not induce the disease [12].
• Localization of S-antigen under various conditions of light or dark adaptation in the rabbit [13].
• It was thought that the S-antigen is taken up by the RPE during phagocytosis of the shed outer segments and is transported to the choriocapillaris [13].

Anatomical context of SAG

• To investigate the in situ expression of S-antigen mRNA, 35S-labeled sense and antisense RNA probes were synthesized from the cDNA to label frozen sections of retina, ciliary body and iris and the treated sections were examined by autoradiography [8].
• In addition, lymphocytes from these monkeys reacted against whole S antigen [11].
• S-antigen, a photoreceptor cell protein, induces a predominantly T-cell mediated autoimmune uveitis in many vertebrate animals, including primates [11].
• Lymphocytes from the draining lymph nodes but not spleens of immunized guinea pigs showed a proliferative response to SAg which was suppressed by CsA administration [14].
• No label, however, was detected in the choroid, suggesting that trans-cellular transport of the S-antigen did not occur [15].

Associations of SAG with chemical compounds

• CsA profoundly reduced DTH skin reactions to SAg and PPD, and prevented vitreal inflammation assessed at 17 days and retinal damage [14].
• These results confirm the glycoprotein nature of S-antigen which may explain the finding of multiple bands found on isoelectric focusing [16].
• Using Triton X-100 to render cells permeable, the quantities of N and M antigen detected in TGEV-infected cells prefixed with either 0.05% glutaraldehyde or 0.1% paraformaldehyde were equal to those of 80% acetone-fixed, TGEV-infected cells while the quantity of S antigen detected was diminished [17].
• Based on the present study, it is therefore suggested that EDTA both locally and systematically reduces the S-antigen induced inflammatory response by decreasing the formation of inflammatory mediators derived from the arachidonic acid cascade [18].

Analytical, diagnostic and therapeutic context of SAG

• From the results of sequencing PCR products and in situ hybridization, we concluded that, in porcine eye, the mRNA for S-antigen is expressed not only in the retina but also in the anterior tissues such as the ciliary epithelium and iris epithelium [8].
• These monoclonal antibodies demonstrated a low antibody titer to the original S-Ag preparation by the ELISA method [19].
• In the control group immunized with S antigen, severe (2+ to 4+) uveoretinitis developed in 70% of the animals [1].
• In radioimmunoassay MAbA9-C6 and MAbA1-G5 do not compete and appear to define unrelated epitopes of S-antigen [6].
• The morphology of S-antigen-induced uveoretinitis in guinea pigs has been studied using transmission electron microscopy [20].

References