Search PubMed⌕ Search

Biomedical subjects

I Gery

Publications and source records attributed to I Gery.

At least 109 records · Page 6Linked to original sources
PubMed1987

Immunoelectron microscopic localization of photoreceptor-specific markers in the monkey retina.

Antibodies for several molecules that function in the visual process were used to localize these molecules in primate rod and cone cells. These antibodies (monoclonal or polyclonal) were prepared against Interphotoreceptor Retinoid-binding Protein (IRBP), S-antigen (S-Ag), opsin, alpha-transducin and also against cyclic GMP (cGMP). Lowicryl-embedded tissues were labeled with secondary antibodies linked to colloidal gold. Although IRBP is predominantly an extracellular protein, the relatively small amount found intracellularly was localized mainly in rods, with little in cones. Opsin, S-Ag and cGMP were found mainly in rod cell outer segments. A polyclonal antiserum raised against transducin-alpha purified from rod outer segments predominantly labeled rod cells, but an antiserum against the carboxyterminal decapeptide of transducin-alpha labeled both rod and cone cells. Thus, most of these specialized molecules are present predominantly in rod cells, confirming major differences in components of the visual cycle in rods and cones.

Animals↗
PubMed1987

IRBP from bovine retina is poorly uveitogenic in guinea pigs and is identical to A-antigen.

Retinal interphotoreceptor retinoid-binding protein (IRBP) is a potent uveitogen in Lewis rats, producing experimental autoimmune uveitis (EAU) reproducibly at doses lower than those of S-antigen (S-Ag). In contrast, IRBP was found to be poorly uveitogenic in three strains of guinea pigs, inducing only minor changes in a small proportion of these animals. On the other hand, S-Ag was found to induce EAU in the majority of immunized guinea pigs, with changes more severe than those induced by IRBP. Unlike the difference in their uveitogenicity, IRBP and S-Ag induced similar levels of specific immune responses in the immunized guinea pigs. The poor uveitogenicity of IRBP in guinea pigs resembles that of A-antigen (A-Ag). The two proteins are also similar in other features and were found in this study to be antigenically identical. It is proposed that IRBP and A-Ag are one and the same protein.

Animals↗
PubMed1987

Immunohistochemical analysis of experimental autoimmune uveoretinitis (EAU) induced by interphotoreceptor retinoid-binding protein (IRBP) in the rat.

Experimental autoimmune uveoretinitis (EAU) was induced in rats by immunization with bovine interphotoreceptor retinoid-binding protein (IRBP) and studied by immunohistochemistry. In general, the IRBP induction of inflammatory cellular components and expression of immune-related antigens on various non-lymphoid cells resembled those provoked by S-antigen (S-Ag). However, differences were found between the two diseases, including: 1) The increase in T suppressor/cytotoxic cells occurred in IRBP EAU more rapidly than in S-Ag EAU. 2) Fewer numbers of non-lymphoid cells expressed major histocompatibility complex class II surface antigens in IRBP EAU than in S-Ag EAU. The immunopathogenic mechanism of EAU induced by these two retinal antigens are discussed.

Animals↗
PubMed1987

Cyclosporine and dexamethasone inhibit T-lymphocyte MHC class II antigens and IL-2 receptor expression in experimental autoimmune uveitis.

Results of recent studies indicated that a monoclonal ART18 antibody recognizes the receptor sites or closely related structures for IL-2 on activated rat T-cells. The major histocompatibility complex (MHC) class II (Ia) antigens (RT1B and RT1D in rat), detected with OX6 antibody, and OX17 antibody, may be present on activated rat T-cells. In the present report, we examined the effect of corticosteroids and cyclosporine (CsA) on the expression of IL-2 receptors and Ia antigens by the T-cells, which constituted the major cellular component of the ocular infiltration during the period of peak ocular inflammatory activity in experimental autoimmune uveoretinitis (EAU). Lewis rats immunized with retinal S-antigen (S-Ag) and treated for a limited time with suboptimal doses of either CsA or Dexamethasone (Dex) subsequently developed EAU. The inflamed ocular tissues were studied using an immunoperoxidase staining technique. CsA treatment resulted not only in the inhibition of IL-2 receptors on T-cells, but also in the prevention of the induction of Ia antigen expression on T-cells and other non-lymphoid cells. Dex treatment resulted in less inhibition of the expression of both class II antigens and IL-2 receptor by the infiltrating T-cells.

Animals↗
PubMed1986

Pinealocyte projections into the mammalian brain revealed with S-antigen antiserum.

Neural processes from mammalian pinealocytes have been discovered in several brain areas. These processes were visualized immunocytochemically in the Djungarian hamster, Phodopus sungorus, with an antiserum against bovine retinal S-antigen and traced as far as the region of the posterior commissure and habenular nuclei. This result indicates that pineal-to-brain connections exist in the mammal, and that the mammalian pineal gland, currently thought of only as a neuroendocrine organ, may communicate directly with select brain regions by way of these projections. The existence of mammalian pinealocyte projections is consistent with the view that these cells are not of glial origin but are derivatives of photoreceptor cells of the pineal complex of lower vertebrates that transmit signals to the brain by neural projections.

Animals↗
PubMed1986

T cell lines mediating experimental autoimmune uveoretinitis (EAU) in the rat.

Long-term S-antigen (S-Ag)-specific T lymphocyte lines were derived from the lymph nodes of immunized Lewis rats that had been pretreated with low-dose cyclophosphamide. The protocol consisted of functional selection by alternating cycles of stimulation with S-Ag presented on syngeneic accessory cells and proliferation in IL 2-containing spleen-conditioned medium, coupled with early phenotypic selection for cells bearing the helper/inducer membrane marker (W3/25), by panning on antibody-coated plastic dishes. This protocol consistently resulted in the rapid generation of in vivo functional cell lines capable of mediating experimental autoimmune uveoretinitis (EAU) when transferred into naive rats at 5 to 10 X 10(6) cells/rat systemically or 1 to 2 X 10(6) cells/rat intravitreally. The disease appeared within 6 to 8 days, usually with minimal anterior chamber involvement, and was often unilateral. Pathologic changes resembled those seen in EAU induced by active immunization. The disease could be transferred without concomitant formation of serum antibodies. The uveitogenic line cells were negative for Ia antigen and positive for the W3/25 membrane marker, which appeared to be stable in long-term culture. They proliferated vigorously in vitro and produced IL 2 in response to S-Ag or Con A, but not to unrelated antigens. The establishment of uveitogenic T helper lymphocyte lines will permit the analysis of the cellular mechanisms involved in EAU in a more defined system than has been available.

Animals↗
PubMed1986

Uveitis induced in primates by interphotoreceptor retinoid-binding protein.

Interphotoreceptor retinoid-binding protein was found to be highly uveitogenic in primates. All six monkeys immunized with bovine interphotoreceptor retinoid-binding protein developed ocular inflammation. The main clinical changes were sheathing of retinal vessels and deep well-circumscribed yellow-white lesions. Histologic changes in the retina included shortening of the outer segments and foci of inflammation, which extended through all retinal layers. Particularly profound were the choroidal changes, such as severe inflammatory infiltration, which often formed focal granulomas with epithelioid and giant cells. Some granulomas had the structure of Dalen-Fuchs nodules. These structures and other histologic changes in the monkeys closely resemble those in uveitic conditions in humans, such as sympathetic ophthalmia or Vogt-Koyanagi-Harada syndrome. These findings show that antigen that localizes specifically in the retina may initiate an immunopathogenic process affecting mainly the choroid.

Animals↗
PubMed1986

S-antigen-like immunoreactivity in a human pineocytoma.

A pineocytoma was investigated by means of immunocytochemistry with the use of a polyclonal antibody against bovine retinal S-antigen. Several cells of this tumor displayed strong S-antigen-like immunoreaction in analogy to certain pinealocytes in normal human pineal organs. This study indicates that S-antigen immunocytochemistry may be applied to characterize tumors of the pineal region.

Antigens↗
PubMed1986

Dual effects of pertussis toxin on lymphoid cells in culture.

Pertussis toxin (Ptx), a component of Bordetella pertussis, is responsible for many of the biological activities of this bacterium, including its potent adjuvant capacity. In attempt to better understand the Ptx activity on the immune response in vivo, we have examined the effect of Ptx on certain lymphoid cell responses in vitro which could be targets for the adjuvant activity of this molecule. Ptx was found to stimulate a variety of cell responses which include (a) increased production and release of interleukin-1 (IL-1) by human monocytes and murine macrophages; (b) co-mitogenesis, in combination with IL-1, in cultures of murine thymocytes; (c) mitogenesis in cultures of various peripheral lymphocytes; (d) increased production of IL-2 in cultures of human blood lymphocytes and rodent splenocytes; and (e) elevated release of IL-3 in cultures of murine spleen cells. In addition to its stimulatory effects, however, Ptx was found to inhibit responses of both mononuclear phagocytes and lymphocytes to other stimuli. Most activities of Ptx in vitro were achieved at the optimal concentration range of 1-10 micrograms/ml, which is 100-1000 times higher than that showing adjuvant effects in vivo. Possible explanations for the dual effect of Ptx and for the discrepancy in doses optimal for the effects in vivo and in vitro are discussed.

Animals↗
PubMed1986

The effects of pertussis toxin on the induction and transfer of experimental autoimmune uveoretinitis.

Experimental autoimmune uveoretinitis (EAU), an intraocular inflammatory disease, is induced in experimental animals by immunization with a retinal specific antigen, S-antigen (S-Ag), emulsified in complete Freund's adjuvant (CFA). The induction of EAU is enhanced by treating S-Ag-immunized animals with Bordetella pertussis. This study examined the effects of a purified component of B. pertussis, pertussis toxin (Ptx), on EAU induction as well as the mode of action of this toxin. Treatment of Lewis rats with Ptx concurrent with S-Ag and CFA enhanced EAU induction as shown by an earlier onset of disease, increased severity of ocular changes, and the reduction of the threshold amount of S-Ag needed for EAU induction. Treatment with Ptx selectively enhanced delayed-type hypersensitivity responses to S-Ag but did not affect specific antibody production. The mode of action of Ptx was analyzed by using the adoptive transfer of EAU by sensitized lymphocytes. Ptx treatment of donor rats enhanced the capacity of lymphocytes to transfer EAU. However, Ptx treatment of recipient rats on the day of cell transfer resulted in a delay in the onset of disease. These results indicate that Ptx enhances the immunopathogenic processes of EAU by enhancing lymphocyte activation and/or increasing their pathogenic activities.

Animals↗
PubMed1986

Different types of pinealocytes as revealed by immunoelectron microscopy of anti-S-antigen and antiopsin binding sites in the pineal organ of toad, frog, hedgehog and bat.

S-antigen- and opsin-immunoreactive sites were studied in the pineal organ of toad (Bufo bufo), frog (Rana tigrina), hedgehog (Erinaceus roumanicus) and bat (Myotis myotis) by light microscopic avidin-biotin-peroxidase and electron microscopic immunoglobulin-gold (immunogold), protein A-gold and avidin-biotin-ferritin techniques. The corresponding retinas served as reference tissues. A large number of photoreceptors of toad and frog pineal organ exhibited either strong or weak S-antigen immunoreaction in the outer segments, perikarya and basal processes. A small number of photoreceptors was S-antigen-negative. In general, the intensity of the reaction was stronger in the immunoreactive outer segments of the pineal organ than in those of the rods and certain cones of the retina. In hedgehog and bat, the perikarya and processes of the pinealocytes were either strongly or weakly S-antigen-positive or they lacked immunogold labeling. By use of an antibovine rhodopsin antiserum either strong or weak opsin immunoreactivity was found in the pineal outer segments of toad and frog. A small number of pineal photoreceptors lacked opsin antigenic sites. Double labeling with both antibovine S-antigen and antibovine opsin antisera showed that the opsin immunoreaction was present in the outer segments which also exhibited S-antigen immunoreaction. In the pineal organ of hedgehog and bat, no opsin immunoreaction was observed with the antisera used. It is proposed that in the pineal organ at least two types of photoreceptors are present: one "rod-type" elaborating rhodopsin accompanied by S-antigen and one (or two) "cone-type(s)" using an unknown photopigment(s). Obviously, the different photoreceptors enable the animal to perceive the different wavelengths of the light spectrum.

Animals↗
PubMed1986

Induction of experimental autoimmune uveoretinitis by T-cell lines.

Experimental autoimmune uveoretinitis was induced in genetically susceptible Lewis rats by passive transfer of T-lymphocyte cell lines from long-term cultures primed against soluble retinal antigen (S-Ag). A continuous T-cell line was established from non-adherent lymph node cells of S-Ag-immunized Lewis rats. The lymphoid cells were propagated in vitro by serially restimulating them with S-Ag in the presence of irradiated syngeneic spleen cells and expanding them in IL-2-containing media. The cell lines exhibited markers specific for T lymphocytes and the majority had the helper phenotype. When naïve rats were inoculated intravenously with anti S-Ag T-cell lines re-exposed to the antigen prior to injection, they developed uveoretinitis with both clinical and histological characteristics in half the time required by S-Ag to induce the disease by active immunization. The rats exhibited a delayed hypersensitivity skin reaction towards S-Ag.

Animals↗
PubMed1986

Lymphocyte migration in the adoptive transfer of EAU.

Experimental autoimmune uveoretinitis (EAU) was transferred into naive male Lewis rats using 1 X 10(8) indium-111 labeled lymphocytes from syngeneic donors immunized with S-antigen. The migration of the lymphocytes was monitored by gamma camera imaging and by determining the accumulation of radioactivity in selected organs. The majority of the cells leave the peritoneal cavity within 24 hr and migrate to the liver, spleen, and thymus. Only a small fraction of the labeled cells reach the eye. However, there were significantly more labeled cells present in eyes that developed EAU as compared with controls using lymphocytes sensitized against bovine serum albumin. These results indicate the adoptive transfer of EAU is a complex process in which only a small number of transferred cells actually reach the eye to induce uveoretinitis.

Animals↗
PubMed1986

Uveoretinitis and pinealitis induced by immunization with interphotoreceptor retinoid-binding protein.

Rats immunized with microgram amounts of interphotoreceptor retinoid-binding protein (IRBP), a glycoprotein which localizes specifically in the eye and pineal gland, developed uveoretinitis and pinealitis. The severity and onset of changes were found to be dose-related and to be enhanced by B. pertussis bacteria. In general, the inflammatory changes induced by IRBP resembled those provoked by S-antigen (S-Ag), but significant differences were noted between the two diseases. The possible usefulness of the new experimental autoimmune disease is discussed.

Animals↗
PubMed1986

Retinal S-antigen: immunocytochemical and immunochemical studies on distribution in animal photoreceptors and pineal organs.

Antiserum against bovine retinal S-antigen, a soluble protein (MW = 50 kDa) thought to be involved in phototransduction, was used in an immunohistochemical and immunochemical study of vertebrate eyes and pineal systems and invertebrate photoreceptor organs. Positive reactions, not seen with antiserum preabsorbed with highly purified S-antigen, were observed in planarian and starfish ocelli; scallop eyes; polychaete eye; crayfish compound eye; lamprey, salmon, frog, turtle, quail and hamster eyes. A specific reaction was also seen in the pineal organ of all the vertebrates examined, albeit weak in turtle and quail. In addition, several structures associated with photoreceptor organs, including the reduced frontal eyes of crayfish, the organ of Bellonci in crayfish eyestalk, and bipolar cells resembling those giving rise to Landolt's clubs in quail and golden hamster retinae, were immunopositive. Immunochemical studies revealed the presence of a single immunopositive band of protein which was similar but not identical in size in all vertebrate eyes and pineal organs (except that of chicken pineal) and invertebrate tissue examined. The wide distribution of positive reaction in photoreceptive tissue indicates that the retinal S-antigen determinant has been highly conserved during evolution.

Animals↗
PubMed1985

Immunocytochemical demonstration of retinal S-antigen in the pineal organ of four mammalian species.

By means of immunocytochemistry retinal S-antigen is selectively demonstrated in retinal photoreceptor cells of the rat and in pinealocytes of the hedgehog, rat, gerbil and cat. Brain areas surrounding the pineal organ are immunonegative. The immunoreactive material is evenly distributed in the perikarya of the cells. Occasionally, inner segments of retinal photoreceptors and processes of pinealocytes are also stained. The outer segments of retinal photoreceptors display a strong immunoreaction. In both pinealocytes and retinal photoreceptors the intensity of the immunoreaction varied considerably among individual cells. The immunocytochemical demonstration of retinal S-antigen in mammalian pinealocytes indicates that these cells still bear characteristics of photoreceptors. This finding is in accord with the concept that mammalian pinealocytes are derived from pineal photoreceptor cells of poikilothermic vertebrates.

Animals↗