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R R Caspi

Publications and source records attributed to R R Caspi.

At least 91 records · Page 5Linked to original sources
PubMed1990

Experimental autoimmune uveoretinitis in mice. Induction by a single eliciting event and dependence on quantitative parameters of immunization.

Experimental autoimmune uveoretinitis (EAU) in the mouse is a recently developed model of ocular autoimmunity. Dependence of disease induction on qualitative and quantitative parameters of immunization was studied in B10.A mice immunized with interphotoreceptor retinoid-binding protein (IRBP). It was found that use of Bordetella pertussis adjuvant as well as its mode of preparation was of critical importance for disease induction; no disease was induced if pertussis adjuvant was omitted. The minimal effective protocol for EAU induction when the vaccine form of B. pertussis adjuvant was used consisted of pretreatment with cyclophosphamide, two divided doses of IRBP in complete Freund's adjuvant (CFA), and two divided doses of B. pertussis vaccine. Any reduction in the immunization schedule resulted in reduced incidence of disease. In contrast, substituting purified B. pertussis toxin (PTX) for the vaccine allowed reduction of the immunization schedule to a single dose of IRBP in CFA and omission of the cyclophosphamide pretreatment. Severity and incidence of disease could be quantitatively controlled by varying the respective doses of IRBP and PTX. In addition, a chronic or an acute clinical course of EAU could be obtained by using either a low-dose or a high-dose immunization, respectively. Establishment of a single dose induction protocol and the quantitation of the immunopathogenic response as a function of the variables of immunization lay the foundation for the further development and utilization of this promising model of ocular autoimmunity.

Adjuvants, Immunologic↗
PubMed1990

Pathology of experimental autoimmune uveoretinitis in mice.

The histopathology and immunopathology of murine experimental autoimmune uveoretinitis (EAU) following active immunization with the interphotoreceptor retinoid-binding protein (IRBP) were studied. The methods used included conventional light microscopy and immunoperoxidase staining. Lesions were located mainly in the uvea and the retina and were characteristically focal. The prominent histopathologic findings in the retina were vasculitis, granuloma, retinal fold, focal serous detachment, and loss of photoreceptors. Granulomas, formation of Dalen-Fuchs nodules, inflammatory cellular infiltration and increase in the thickness of the choroid and ciliary body were frequent findings. Subretinal neovascularization occurred in 10% of the experimental animals. Mild to moderate inflammation was also noted in the vitreous. The predominant infiltrating cells in the retinal and uveal granuloma and the Dalen-Fuchs nodules were macrophages. In contrast, the predominant infiltrating cell types in the vitreous were T helper/inducer lymphocytes. T suppressor/cytotoxic cells were rarely seen. Expression of Ia antigens on the ocular cells was confined to the immediate area of the inflammatory sites. The kinetics of histopathology showed two peaks at the 5th and 10th week after immunization, suggesting a relapsing course of the disease.

Animals↗
PubMed1990

The mouse as a model of experimental autoimmune uveoretinitis (EAU).

An EAU model has been developed in the mouse using the retinal soluble antigen (SAg), and the interphotoreceptor retinoid-binding protein (IRBP). Immunogenetic studies indicate that sensitivity to disease is H-2 dependent, but some data suggest that non-MHC genes may also contribute to the regulation of EAU. IRBP was a more potent uveitogen than SAg. Ability to mount lymphocyte and antibody responses was exhibited both by EAU-susceptible and by EAU-resistant strains, and could not be used as a predictive parameter. Dependence of disease induction on variables of immunization was studied in B10.A mice (I-Ak) immunized with IRBP. Use of Bordetella pertussis as additional adjuvant was a prerequisite for successful disease induction. Use of purified pertussis toxin (PTX), rather than a suspension of pertussis bacteria, allowed reduction of the immunization protocol to a single dose of IRBP in CFA. Severity and incidence of disease, as well as its clinical course, were directly affected by the dose of antigen and PTX, and could be controlled by varying their respective doses. A spectrum of disease, from hyperacute to chronic, could be obtained. The chronic type of EAU tended to relapse, with lesions reappearing after a brief period of essential quiescence. The special advantages of the murine EAU model for the study of ocular autoimmunity are discussed.

Animals↗
PubMed1990

Enhancing effect of cyclosporins A and G on bone marrow colony formation.

The development of the number of colonies (cell colony-forming units, CFU-C) in soft agar from normal mouse bone marrow (BM) cells was enhanced 60% when total bone marrow cells (BMC) were preincubated for 1 h with either cyclosporin A (CsA) or cyclosporin G (CsG) before plating. Using cell fractionation techniques we found that the removal of macrophages enhanced CFU-C in noncyclosporin-treated BM and that cyclosporins mediated an additional enhancing effect. A similar enhancing effect on CFU-C in noncyclosporin-treated BM was obtained by depleting it of total T cells or Lyt-2.2+ cells. However, CFU-C growth in the residual BM population was no longer enhanced by cyclosporin. Conversely, removal of Lyt-1.2+ cells did not enhance CFU-C in noncyclosporin-treated BM, but the CFU-C in this population were enhanced by cyclosporin treatment. These results suggest that CsA and CsG can increase the cloning efficiency of normal mouse BMC, possibly by inhibiting an endogenous Lyt-2.2+ suppressor cell.

Animals↗
PubMed1989

Glial cells as suppressor cells: characterization of the inhibitory function.

Rat retinal glial cells (Müller cells) profoundly suppress antigen-driven activation, as well as the subsequent interleukin-2 (IL-2)-dependent expansion of autoimmune and conventional-immune syngeneic T-helper lymphocytes, through a contact-dependent mechanism. Characterization of this inhibitory function showed that some activation parameters of autoimmune T-helper lymphocytes specific to the retinal soluble antigen, responding to antigen presented on syngeneic antigen-presenting cells, were differentially affected by coculture with Müller cells. In contrast to endogenous IL-2 production, IL-2-receptor generation and proliferation, the production of interleukin-3 and of interferon-gamma were not inhibited. Inhibition of IL-2-supported proliferation of cells which had already generated the IL-2 receptor was markedly potentiated in the presence of the specific antigen, in a dose-dependent manner. The extent of inhibition was proportional to the number of Müller cells in the culture. The suppression appeared not to involve a major histocompatibility complex (MHC) Class II-related interaction and could act across allogeneic and even xenogeneic barriers. Inhibition affected normal lymphocytes, including primed T cells responding to antigen or to IL-2, unprimed spleen cells responding to the T-cell mitogen concanavalin A (Con-A) and, to a lesser extent, unprimed spleen cells responding to the B-cell mitogen bacterial lipopolysaccharide (LPS). Several permanently transformed cell lines of mouse, rat and human origin were not affected. These results may suggest participation of organ-resident cells in regulation of locally occurring immune processes.

Animals↗
PubMed1988

Characterization of a suppressor cell line which downgrades experimental autoimmune uveoretinitis in the rat.

A Ts lymphocyte line was isolated from spleens of rats primed with the retinal soluble Ag (SAg) in the anterior chamber of the eye. This line could inhibit in vitro SAg-driven proliferation of uveitogenic Th lymphocytes, in a radioresistant, Ag-independent manner. Adoptively transferred Ts line cells were found to downgrade experimental autoimmune uveoretinitis in actively immunized syngeneic recipients. The initial surface phenotype (OX8+) of the Ts line was unstable in vitro, however, the cells expressed suppressor function irrespective of phenotype. The mechanism of suppression did not appear to involve consumption of IL-2 or direct cytolysis of uveitogenic Th lymphocytes, but rather the production of a soluble suppressor factor. These findings may suggest an in vivo role for suppressor lymphocytes, capable of inhibiting primed Th cells, in the regulation of experimental autoimmune uveoretinitis.

Animals↗
PubMed1988

Intraocular trafficking of lymphocytes in locally induced experimental autoimmune uveoretinitis (EAU).

Experimental autoimmune uveoretinitis (EAU) was induced in naive Lewis rats by intravitreal adoptive transfer of 10(6) long-term S-antigen (S-Ag)-specific syngeneic T-lymphocyte lines of helper/inducer phenotype (ThS). These cells were stimulated with the T-cell mitogen concanavalin A (Con A) in culture for 48 hr and subsequently labeled with tritiated thymidine. Lymph node cells (LNC) cultured in parallel were used as controls. Histopathology and light microscopic autoradiography of the ocular tissue was performed at several time points to analyze the cell migration in relation to the development of EAU. The disappearance of both types of lymphocytes from the vitreous was similar and large numbers of host leukocytes were attracted into the vitreous. However, significantly more S-Ag-specific cells penetrated the retina and induced EAU (P less than 0.008). These results suggest that the development of EAU by intravitreal injection of S-Ag-specific T lymphocytes occurs by the migration of antigen-specific cells into the retina and recognition of the specific antigen, with subsequent release of soluble mediators that interact with the host effector cells, ultimately leading to specific photoreceptor damage.

Animals↗
PubMed1988

Glial retinal Müller cells produce IL-1 activity and have a dual effect on autoimmune T helper lymphocytes. Antigen presentation manifested after removal of suppressive activity.

The Müller cell is the major glial element of the mammalian retina. It can be induced to express MHC class II determinants in culture, when exposed to supernatant from activated lymphocytes. In an in vitro co-culture system, Müller cells had been shown to exert a profound inhibitory influence on Ag- and IL-2-driven proliferation of Th cell lines. In the present report we demonstrate that Müller cells can produce IL-1 activity, and that in conditions where their inhibitory action is suppressed, they display the capacity to efficiently function as APC. Mildly trypsinized and glutaraldehyde-fixed Müller cells that had been preincubated with Ag and IFN-gamma-containing rat spleen conditioned medium were able to present Ag to an S-Ag specific Th lymphocyte line, which has the capacity to induce a severe uveoretinitis in rats. Addition of the Ag after fixation did not result in presentation, showing that Müller cells had to process the nominal Ag into an immunogenic form. It was also found that the efficiency of presentation was greatly increased in the presence of naive syngeneic or allogeneic accessory cells. This enhancing effect could not be reproduced with rIL-1. This report extends our ongoing study of interactions between the retinal glial Müller cell and T lymphocytes. The results show that these interactions can be diverse, even opposite in different conditions, and suggest the possibility that Müller cells could play a determining role in the course of immune reactions at the level of the neuro-retina.

Animals↗
PubMed1988

A new model of autoimmune disease. Experimental autoimmune uveoretinitis induced in mice with two different retinal antigens.

Experimental autoimmune uveoretinitis (EAU) is an organ-specific, T lymphocyte-mediated autoimmune disease, which serves as a model for several human ocular inflammations of an apparently autoimmune nature. EAU pathology in some rodents and in monkeys can readily be induced by immunization with several different retinal proteins; however, advancing research into the cellular mechanisms of this disease has raised the need for an EAU model in an immunologically and genetically well defined species. We report here the induction of EAU in the mouse, which has hitherto been considered a species refractory to EAU, with two retinal Ag, the retinal soluble Ag and the interphotoreceptor retinoid-binding protein. Although all the mouse strains tested exhibited lymphocyte responses and antibody titers to both retinal Ag, EAU was inducible in only some of the strains, and the uveitogenic responses to retinal soluble Ag and interphotoreceptor retinoid-binding protein appeared to be mutually exclusive. The EAU model in mice was found to differ in several respects from the EAU model in other rodent species. Induction of the disease was achieved with a relatively high dose of Ag and an intensified immunization protocol, and the onset of disease was later, the duration was longer, and the course was less acute. Anterior segment involvement was slight or nonexistent, and damage to the retina and uvea was of a focal rather than of a diffuse nature. Murine EAU appeared to approximate some types of human uveitis more closely than the EAU models described in other rodent species with respect to its pathologic manifestations as well as its more chronic course. The relatively longer duration of the active stage of disease in murine EAU should facilitate therapeutic intervention in established disease, which was not feasible in the more acute models of EAU. The extensive knowledge of the immunologic parameters of the mouse and the availability of genetically defined strains should be of great value in the study of cellular mechanisms and immunogenetics of ocular autoimmune disease.

Animals↗
PubMed1988

Differential effects of cyclosporins A and G on functional activation of a T-helper-lymphocyte line mediating experimental autoimmune uveoretinitis.

The effect and relative efficiency of cyclosporin A (CsA) and cyclosporin G (CsG) on suppressing the activation of primed autoimmune rat T-helper lymphocytes were assayed. The autoimmune T-helper cells (ThS) are a long-term line specific to the retinal soluble antigen (SAg) and can adoptively transfer experimental autoimmune uveoretinitis (EAU), after in vitro reactivation with antigen or mitogen, to naive syngeneic hosts. Antigen-driven production of interleukin-2 (IL-2) and antigen-driven proliferation were inhibited in a dose-dependent manner and to a similar extent at each of the respective cyclosporin concentrations. CsA was 8-10 times more potent than CsG, with ID50-CsA occurring at 0.5 to 2 ng/ml, and ID50-CsG at 5 to 20 ng/ml, depending on the experiment and the cyclosporin batch. Addition of exogenous lymphokines in the form of rat spleen concanavalin A (Con A)-conditioned medium (SCM) or recombinant IL-2 (but not recombinant IL-1) was able to reverse only about half of the inhibition, as measured along the linear part of the dose-response curve. Inhibition of IL-2 production was lost if a maximally inhibitory dose of cyclosporin was added to the cultures later than 8 hr after antigen stimulation, while proliferation was still suppressed to 50% by cyclosporin added as late as 12 hr and could not be restored by addition of SCM. Both cyclosporins at concentrations that blocked proliferation and IL-2 production significantly suppressed the generation of high-affinity and low-affinity IL-2 receptors by ThS in response to antigen (as assayed by direct binding of 125I-IL-2). These results suggest that CsA and CsG inhibit antigen-induced expansion of ThS by interfering with more than one activation step. In contrast, the in vitro activation of the uveitogenic potential of ThS cells, incubated with antigen in the presence of CsA or CsG and adoptively transferred into untreated recipients, was not affected by the cyclosporins. Thus, triggering of the pathogenic potential of primed autoimmune T-helper lymphocytes can take place in the presence of cyclosporin and in the absence of cellular proliferation.

Animals↗
PubMed1988

Dynamics of experimental autoimmune uveoretinitis induced by adoptive transfer of S-antigen-specific T cell line.

Long-term S-antigen (S-Ag) specific T lymphocyte lines can induce experimental autoimmune uveoretinitis (EAU) when transferred into naive rats systemically or intravitreally. The uveitogenic lymphocyte line (ThS) stains positively for the ART 18 (IL-2 receptor) and W3/25 (T helper/inducer); negatively for OX6 (RT1B) and OX8 (T suppressor/cytotoxic cells). The inflammation induced by systemic or intravitreal transfer of the ThS line was studied with respect to the surface markers of the infiltrating cells, as well as the markers expressed by the resident ocular cells, by immunohistopathological techniques. On day 4 to 5 after systemic injection of the ThS line, rare T cells (W3/25+, ART 18+) and macrophages (OX42+, OX6+) surrounded by some resident cells that expressed MHC class II antigens were identified in the ciliary body and choroid. Shortly thereafter (10-20 hr) more macrophages, polymorphonuclear leukocytes, and T lymphocytes (W3/25+, then OX8+) appeared in the inflamed eye. The kinetics was similar to EAU induced by active immunization. The rats with severe disease expressed the MHC class II antigens on large numbers of resident cells in the eye. Intravitreally transferred ThS cells migrated to the retina within 24 hr of transfer. Infiltration of macrophages (OX6+, OX42+) and other T lymphocytes (OX6+, W3/25+ or OX8+), in conjunction with photoreceptor damage, were observed within the next 24-48 hr. The cells with the ThS markers disappeared from the eye on day 4-5 post transfer. These findings suggest that the ThS line can recognize the photoreceptor S-Ag in vivo.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

The biological activity and immunotherapeutic properties of AS-101, a synthetic organotellurium compound.

AS-101 (ammonium trichloro[dioxoethylene-O,O'-]tellurate) is a newly developed synthetic compound with immunomodulating properties and minimal toxicity. We evaluated the effects of AS-101 on various parameters of the activation and function of immunocompetent cells. AS-101 induced IL-2 receptor expression, IL-2 production and proliferation by human and mouse lymphocytes in vitro and enhanced the production colony-stimulating factor (CSF) by mouse spleen cells. In vivo treatment of Balb/c mice with AS-101 caused a significantly increased production of IL-2 and CSF in vitro in the presence of mitogen. When administered systemically to mice, AS-101 mediated antitumor effects in vivo. These results suggest that AS-101 is an active biological response modifier, which might have potential use in the treatment of conditions such as malignancy, AIDS and some types of immune deficiency.

Adjuvants, Immunologic↗
PubMed1987

Organ-resident, nonlymphoid cells suppress proliferation of autoimmune T-helper lymphocytes.

Local presentation of autoantigen by organ-resident cells inappropriately expressing Ia determinants has been implicated in organ-specific autoimmunity. Experimental autoimmune uveoretinitis, induced in rats by immunization with retinal soluble antigen, is used as a model of organ-specific autoimmunity. In an in vitro system derived from this model, uveitogenic rat T-helper lymphocytes specific to the retinal soluble antigen, or control T-helper lymphocytes reactive to the purified protein derivative of tuberculin, were cocultured with Ia-expressing syngeneic retinal glial cells (Müller cells) in the presence of specific antigen. Antigen presentation was not apparent under ordinary culture conditions, and the Müller cells profoundly suppressed the proliferative response of primed T-helper lymphocytes to antigen presented on conventional antigen-presenting cells, as well as their subsequent interleukin-2 (IL-2)-dependent expansion. Suppression of proliferation was accompanied by inhibition of IL-2 production in response to antigen, as well as by reduction in high-affinity IL-2 receptor expression, and proceeded via a contact-dependent mechanism. These results suggest a role for locally acting suppression mechanisms in immune regulation and maintenance of tissue homeostasis.

Animals↗
PubMed1987

Antigen-directed retention of an autoimmune T-cell line.

We have used the T-cell-mediated, organ-specific autoimmune disease model of experimental autoimmune uveoretinitis (EAU) in the Lewis rat to study antigen-directed retention of autoimmune T helper cells in the target organ. We have compared the migration into the eye of two T-helper-cell lines: ThS, specific for retinal S antigen (S-Ag), that is uveitogenic to normal syngenic recipients, and ThP, specific to purified protein derivative of tuberculin (PPD), that is non-uveitogenic. The retention of adoptively transferred 51Cr-labeled ThS and ThP was studied up to the stage of disease induction in unprimed animals, during the acute stage of EAU induced by active immunization with S-Ag, and during the acute stage of a uveitis induced by a nonocular antigen (bovine serum albumin, BSA). Low numbers of cells from the two lymphocyte lines were detected in the eyes of unprimed animals, with no obvious increase of ThS over ThP, despite induction of EAU in the recipient animals by the injected ThS cells. In S-Ag-induced EAU many more ThS accumulated in the eye than ThP. In BSA uveitis both T-cell lines accumulated in the eye to the same extent, but more than in control noninflamed eyes. These results demonstrate the presence of increased antigen-specific retention of circulating autoimmune T helper lymphocytes during the acute stage of an ocular antigen-specific, but not ocular antigen nonspecific, inflammation. Since detectable accumulation of ThS cells in the eye was not a prerequisite for the induction of EAU, this phenomenon appears to be the result, rather than the cause, of the autoimmune process.

Animals↗
PubMed1986

A rapid one-step multiwell tray test for release of soluble mediators.

A simple one-stage bioassay for testing the release of diffusible mediators from cells has been developed in a modified standard 96-well tissue culture tray. The method is based on connecting the adjacent wells containing the producer and the indicator cells, so as to allow free passage of the culture supernatant, but not of the cells, between the connected wells. This method obviates the use of semipermeable membranes, requires minimal numbers of producer cells, and allows the harvesting of replicate cultures by using standard cell harvesting equipment.

Biological Assay↗
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

A comparison of the effectiveness of cyclosporine A, D, and G in the treatment of experimental autoimmune uveitis in rats.

Cyclosporine A (CsA), one compound in the family of cyclosporines, has effectively modulated the course of S-antigen induced experimental autoimmune uveitis (EAU). Cyclosporines G (CsG) and D (CsD), related to CsA in structure, were evaluated in their ability to prevent or modulate EAU in Lewis rats. 10 mg/kg/day IM of CsA effectively prevented the expression of EAU when therapy began on the day of immunization, while the same dosage of CsG prevented EAU in 81% of animals, and CsD only in 33%. Higher concentrations of CsG (40 mg/kg/day) did effectively block manifestations of the disease. Topical administration of CsG did not prevent the expression of disease but local protection was seen when the 500 micrograms CsG was placed intracamerally into only one eye. The in vitro comparison of these cyclosporines' capacity to alter proliferation and IL-2 release of a rat T-cell line capable of inducing EAU showed marked differences. CsA appeared to be most effective at abrogating these cellular functions at all concentrations tested, while CsD was least effective. CsG, however, approached the effectiveness of CsA. CsG is felt to be markedly less nephrotoxic than CsA, the secondary effect that is most commonly encountered, and could potentially be useful in the treatment of human intra-ocular inflammatory disease.

Animals↗