Cellular Autoimmune Response Research Articles

Involvement of Peritoneal Dendritic Cells in the Induction of Autoimmune Prostatitis

We have been working within a model of autoimmune prostatitis induced by the intraperitoneal administration of saline extract of rat male accessory glands (RAG) associated to liposomes. The intraperitoneal administration of RAG-liposomes elicits both primary and secondary cellular autoimmune responses to RAG as well as organ-specific lesions. To evaluate the participation of dendritic cells (DC) in the induction of the autoimmune response, we purified peritoneal DC (PDC) after a single injection of RAG-liposomes and we characterized this population by morphology and phenotype. Based on adherence and morphologic criteria, we determined that PDC comprised approximately 1% of the total peritoneal cells. The ultrastructure of the dendritic cell enriched fraction was assessed by electron microscopy. By FACS analysis, PDC showed a two to three-fold increase in expression of the IA molecule compared to macrophages. They expressed low but positive levels of the CD14 marker, and intermediate levels of both CD11b (Mac-1) and CD54 (ICAM-1) adhesion molecules. In addition, PDC transferred either intra-venously or intraperitoneally efficiently elicited the autoimmune response to RAG in normal receptors. These results support the involvement of peritoneal dendritic cells in the induction of autoimmune prostatitis, modifying the idea of macrophages as the single antigen presenting cell in the peritoneal cavity.

Autoantibodies against rat prostate antigens. Association of specific IGG2b and IGG2c with the DTH response.

Although autoimmune response against most tissues in the body has been extensively described, very little is known about autoimmune response against prostate antigens either in humans or animals. In this work we studied the autoimmune response elicited against rat prostate (RP) in Wistar rats immunized with a chemically modified extract of syngeneic male sex accessory glands (MRAG). We observed that one immunization was enough for the induction of positive delayed-type hypersensitivity test (DTH), which was higher on day 15 than on day 30. It was also enough to induce IgG autoantibodies to RP although a second injection was necessary to obtain a more frequent occurrence and a greater reactivity. The autoantibodies against RP were directed mainly to the cytosolic fraction and reacted at least with two molecules of 43 and 20 KD. Sera obtained on days 30 and 45 showed presence of specific IgG, IgA and IgM. Specific IgG2b and IgG2c were found on both days. On day 30 none of the sera presented IgG2a anti-RP, while on day 45 only 38% of the sera were considered positive for this isotype. No IgG1 anti-RP was detected in any serum of either bleeding. Direct immunofluorescence staining showed intense immunofluorescence in prostate epithelium, mainly in the apical zone of the gland, in animals that had received two immunizations with MRAG-CFA. No positive staining was seen in prostates obtained on day 30 after just one immunization, in sections of normal prostates or in sections of other rat organs. Our data indicate that the main isotypes involved in this autoimmune phenomenon are IgG2b and IgG2c. A strong association between the cellular autoimmune response measured by the DTH response and the IgG2b and IgG2c isotype was found at early stages of the disease. Since the DTH response and the IgG2b isotype have been previously associated with Th1-like activity in rats, our results suggest that Th1-like cells could be playing an active role in early stages of this disease.

Does autoimmunity to S-antigen play a role in Fuchs' heterochromic cyclitis?

Autoimmunity directed against retinal or choroidal antigens has been suggested to play a role in the chorioretinal lesions observed in patients with Fuchs' heterochromic cyclitis. This hypothesis was addressed and patients with Fuchs' heterochromic cyclitis were tested for cellular immunity (migration inhibitory factor assay) against human retinal S-antigen. A significantly higher percentage of patients with Fuchs' heterochromic cyclitis had a positive cellular autoimmune response to S-antigen than healthy controls and other patients with anterior uveitis. This finding is remarkable since Fuchs' heterochromic cyclitis is generally classified as an anterior uveitis and patients with Fuchs' heterochromic cyclitis without chorioretinal lesions also had a positive test. In view of these results and a sensitisation against a corneal antigen reported earlier in Fuchs' heterochromic cyclitis, it is suggested that a chronic low grade grade anterior uveitis or chorioretinitis of unknown origin may cause the release of potent autoantigens in these patients.

Characterization of the mouse autoantigen La (SS-B). Identification of conserved RNA-binding motifs, a putative ATP binding site and reactivity of recombinant protein with poly(U) and human autoantibodies.

To facilitate the study of autoimmunity to the nuclear Ag La (SS-B) we have isolated and characterized cDNA encoding the mouse La (SS-B) protein. Mouse La (SS-B) protein has 76.7% identity to both human and bovine La (SS-B) proteins and the previously recognized RNP-binding motifs were noted to be highly conserved across the three species. Examination of the primary sequence of human and bovine La (SS-B) newly identifies the site of a potential ATP-binding motif G/AXXXXGK which is preserved in mouse La (SS-B) despite a unique 16 amino acid insertion present in this region of the mouse protein. Analysis of mouse genomic DNA suggests a single gene encodes mouse La (SS-B) and no restriction fragment polymorphisms were identified in the three mouse strains investigated. Two alternate 5' untranslated regions were identified in mouse La (SS-B) cDNA and La (SS-B) mRNA was identified in a wide range of murine tissues consistent with its ubiquitous expression. Recombinant mouse La (SS-B) protein purified from Escherichia coli was shown to bind to poly(U) agarose and to react with sera containing anti-La (SS-B) antibodies obtained from patients with Sjögren's syndrome. The ability to produce recombinant mouse La (SS-B) should provide a valuable reagent for the study of the cellular autoimmune response as well as immunologic tolerance to La (SS-B) Ag in mice.

I-Aα k transgene Pairs with I-Aβ b gene and protects C57BL10 mice from developing autoimmune myasthenia gravis

The I-Aβ gene has been implicated in the pathogenesis of experimental autoimmune myasthenia gravis (EAMG), with amino acids at positions 67, 70, and 71 of the I-Aβ b chain that play a crucial role. In addition, the cell surface expression of the I-E molecule in C57BL10.Eα k transgenic mice was associated with the partially suppressed serum anti-acetylcholine receptor antibody and clinical expression of EAMG. In this study, the contribution of the I-Aα gene and the Aβ b:Aα k transpair in EAMG pathogenesis is assessed. The I-Aα k transgene was introduced into the B10 (Aβ b:Aα b) strain, and the I-Aα k chain was paired with I-Aβ b; therefore, the Aβ b:Aα k complex was expressed on the cell surface. Expression of the Aβ b:Aα k transpair in C57BL10 transgenic mice suppressed the cellular and humoral autoimmune responses to acetylcholine receptors (AChR), reduced the amount of muscle AChR bound with antibody, and significantly reduced the incidence of muscle weakness and its associated abnormal electrophysiological response.

Human asialoglycoprotein receptor as an autoantigen in chronic hepatitis

ASGPR may play a role in the pathogenesis of autoimmune chronic liver diseases. Several lines of evidence support this hypothesis. Antibodies to rabbit ASGPR could be found in various inflammatory liver diseases. In contrast, ASGPR preparations derived from human liver (h-ASGPR) were recognized predominantly by sera from patients with ai-CAH. Moreover, anti-h-ASGPR showed a close correlation to the inflammatory activity of ai-CAH both in terms of prevalence (88% in histologically proven active diseases), immunoglobulin class (IgM antibodies restricted to active inflammation) and behavior during treatment. Anti-h-ASGPR secretion could also be found in vitro, when PBL of patients were stimulated in cell culture. Anti-h-ASGPR antibodies did not correlate with a subgroup of ai-CAH; they also occurred in nearly 15% of patients with PBC. Other inflammatory liver diseases, as well as nonhepatic autoimmune disorders, seldom exhibited anti-h-ASGPR (less than 5%). Additionally, PBL and T-cell clones obtained from liver biopsies in patients with ai-CAH and PBC responded to h-ASGPR. Liver-infiltrating T cells were predominantly of CD4 phenotype and HLA class II restricted. Thus, the human ASGPR has been shown to represent a common target for humoral and cellular autoimmune response in chronic hepatitis probably contributing to disease induction or perpetuation.

Cardiac myosin-induced myocarditis as a model of postinfectious autoimmunity.

Immunization with purified cardiac myosin induces autoimmune myocarditis in A strain mice. Because this disease parallels Coxsackievirus B3 (CB3)-induced myocarditis in many respects, we are now using the immunization model as a virus-free system to study certain forms of immunologically-mediated heart disease. In the present article we will describe several characteristics of the humoral and cellular autoimmune response acting in myosin-induced myocarditis. Furthermore, we discuss hypotheses which might explain how myosin-reactive T cells recognize and attack the heart tissue.

Autoimmune responsiveness to retinal IRBP, S-antigen and opsin in proliferative vitreoretinopathy

Proliferative vitreoretinopathy (PVR) was induced in rabbits by intravitreal injection of homologous fibroblasts. During the 8 weeks after injection the immune responsiveness to three purified retinal autoantigens was studied. From 2 weeks after injection, animals that developed serious forms of PVR exhibited definite mitotic responses of their lymphocytes to stimulation by the retinal antigens. These responses could consistently be demonstrated for S-antigen and interphotoreceptor retinoid-binding protein (IRBP) during the subsequent period of examination. Marked responses were also noted to opsin, however, their occurrence was more variable. In mild forms of PVR or in controls the responses were weak or absent. This showed that the elevated cellular reactivities were induced by the development of PVR and not by some other experimental factor. Humoral immune responses to the three antigens were absent (as assayed by ELISA). The control groups did not exhibit any elevated immune responsiveness. There appears to be accumulating evidence that inflammation may play a role in the development of PVR. The present results indicate that cellular autoimmune responses to photoreceptor antigens are a secondary phenomenon in PVR, nevertheless, they may be an important factor in the subsequent development of severe PVR. This autosensitization may consequently be taken into consideration in the treatment of complicated human PVR.

Cellular Immune Response to la Induction by Intraocular Gamma-Interferon

BALB/c mice and Lewis rats were injected intraocularly with recombinant gamma-interferon (IFN-gamma). The distribution of Ia antigens and cellular infiltrates was studied over a 21-day time course. In mice, Ia antigens were induced on cells in the corneal stroma, corneal endothelium, iris, ciliary body, retinal pigment epithelium and cells in the retina. No detectable cellular infiltrate accompanied class II major histocompatibility (MHC) antigen induction in mice. In rats, cells in all of the intraocular tissues mentioned above were induced to express Ia antigens. However, in distinct contrast to mice, the induction of Ia antigens on intraocular structures in rats was accompanied by intense cellular inflammation composed predominantly of polymorphonuclear cells. These findings demonstrate that aberrant Ia expression on intraocular tissues by IFN-gamma is not sufficient to elicit a cellular autoimmune response in mice. The observed species-related differences in cellular immune response to class II MHC antigen induction on intraocular tissues parallels the susceptibility of mice and rats to experimental autoimmune uveitis.

Stress proteins, arthritis, and autoimmunity.

Stress proteins have been highly conserved during evolution not only because of their fundamental importance in the response of the cell to stressful assaults, but also because they have critical roles in cellular activation and cell growth, regulation of protein function, protein transport, and protein assembly. Research focusing on the basic cell biology of stress proteins is intense at present, and will surely continue to be for some time to come. Of particular interest to immunologists and rheumatologists is the convergence of data in several fields that suggest that stress proteins in microorganisms that commonly infect humans may be triggers of humoral and cellular autoimmune responses and consequent overt autoimmune disease expression. Thus, stress proteins of M tuberculosis and other bacteria are close homologs of stress proteins in mammals, and may be involved in the pathogenesis of adjuvant-induced arthritis in rats and, possibly, of RA and reactive arthritis in humans. A great deal of work remains to be done in this area, including (a) generation and propagation of specifically reactive T cell clones, (b) molecular delineation of the immune recognition elements and critical epitopes shared by microbial stress proteins and host proteins, (c) definition of the relative contribution of alpha beta and gamma delta TCRs to T cell reactivity to stress proteins, and (d) clarification of the circumstances that enable persistent T cell autoreactivity to stress proteins. The data at hand are sufficiently compelling, however, to suggest that vaccination against T cells that recognize stress proteins may eventually become part of our therapeutic armamentarium to prevent or cure some forms of arthritis.(ABSTRACT TRUNCATED AT 250 WORDS)

Molecular aspects of autoimmunity

Sustained humoral and/or cellular autoimmune responses are currently thought to be the primary causes of a wide spectrum of systemic and organ-specific human and animal disease. Although a very good picture of the immunopathological characteristics of these diseases has emerged, their etiologies remain unknown. Studies initiated to define these disease at the molecular genetic level were the subject of a recent meeting ∗ in Ville D'Esterel, Canada. Because these diseases are diverse and enormously complex, several avenues of investigation have been pursued. The primary focus of this meeting was the tripartite system of immunoglobulin (lg), T-cell antigen receptor (TCR) and major histocompatibility complex (MHC) genes.

Participation of different cellular types in the enhancement of autoimmune response of old animals to sex accessory glands in male rats: importance of macrophages

In a previous work, we showed that the immunization of male rats, 3 and 12 months old, with saline extract of rat male accessory glands chemically modified (MRAG) and human serum albumin (HSA) induced a higher humoral and cellular autoimmune response in old animals than in young ones. We have also demonstrated that the facilitation of the autoimmune response is transferred by spleen total cells of 12-month-old animals. The immune response to HSA was not modified. In this work, the cellular type involved in such facilitation was analyzed. For this transference experiment, cells enriched in T and B lymphocytes and macrophages were used. The results showed that the macrophage is the main cellular type involved. However, the transference was only total with the three cellular types together. The study, performed with macophages pulsed in vivo with MRAG-HSA and then transferred to normal recipients, indicated that although the macrophages from young and old animals were capable of presenting the antigens, the latter did this with significantly greater efficiency for the autoantigen.

Antigen receptor genes in autoimmune B and T cells.

Abnormal humoral and/or cellular autoimmune responses of sufficient magnitude and duration are sometimes considered the primary, and at other times secondary, contributors to many human and animal diseases (l), Clinically, the wide spectrum of autoimmune diseases has been divided into two main categories: systemic and organ-specific diseases. Types of autoimmune diseases frequenty overlap, and more than one autoimmune disorder tends to occur in the same individual. Among the non-organ-specific diseases, systemic lupus erythematosus serves as the prototype.

Multiple low-dose streptozotocin-induced diabetes in the mouse: further evidence for involvement of an anti-B cell cytotoxic cellular auto-immune response.

Anti-B cell auto-immunity may play a role in the pathogenesis of diabetes in mice resulting from multiple subdiabetogenic doses of the pancreatic B cell toxin, streptozotocin. In the present study we have investigated the cytotoxic anti-B cell response in these mice. A major role for B lymphocytes, macrophages, or their products in the cytotoxic response originally detected in vitro was eliminated by passing splenocytes from the mice treated with multiple subdiabetogenic doses of streptozotocin over a nylon wool column. The removal of the adherent cells enhanced the cytotoxicity against a rat insulinoma cell line in vitro by that expected due to enrichment of T-lymphocytes by approximately two-fold. The induction of diabetes after multiple subdiabetogenic doses of streptozotocin is strain dependent. Mice of five strains were immunized with rat insulinoma cells, but only splenocytes from the two strains susceptible to multiple subdiabetogenic doses of streptozotocin demonstrated a significant cytotoxic response against the rat insulinoma cells in vitro. Mice pre-immunized with either the rat insulinoma cells or with syngeneic islets labelled in vitro with the hapten trinitrophenol developed hyperglycaemia more rapidly than control mice after multiple subdiabetogenic doses of streptozotocin. In the latter experiment the control mice immunized with complete Freund's adjuvant alone also became hyperglycaemic after a modified multiple subdiabetogenic dose of streptozotocin that did not cause diabetes in non-immunized mice. In mice pre-treated with either adjuvant or cyclophosphamide and then given a modified multiple subdiabetogenic dose of streptozotocin (35 mg/kg X 5 rather than 40 mg/kg) the degree of hyperglycaemia was reduced and there was no protective effect of cyclophosphamide.(ABSTRACT TRUNCATED AT 250 WORDS)

Potentiation of autoimmune response in rats infected with Toxoplasma gondii. Effect of the infection route.

The aim of this report is to describe the influence of the way of infection with 3 X 10(3) trophozoites of Toxoplasma gondii on the auto- and heteroimmune responses of rats immunized with chemically modified rat male accessory glands (MRAG) and human serum albumin (HSA) 6 and 36 days after infection. The delayed hypersensitivity (DTH) response to MRAG was potentiated in rats infected in thymus proximity (p less than 0.02) when compared with rats only immunized. The parasites introduced intraperitoneally did not modify the cellular autoimmune response. The titers of hemagglutinating antibodies to MRAG were increased in animals infected by both ways (p less than 0.05). The response to HSA did not show significant difference between the infected and uninfected rats. Thymic involution and proliferation of lymphocytes and plasma cells were observed at 6 and 52 days post-infection only in rats infected in thymus proximity (p less than 0.05). A correlation between the potentiation of cellular autoimmune response and the injection of parasites in thymus proximity was observed.

Evaluation of the immunosuppression in an experimental model of autoimmunity: Suppressor activity of spleen cells from cyclophosphamide-treated rats

Rats immunized with chemically modified rat male accessory glands (MRAG) and injected 3 days later with cyclophosphamide (CY) were unable to develop humoral and cellular immune response to the autoantigen of MRAG. The present report demonstrates that the spleen mononuclear (SpM) cells transference from rats injected with CY 3 days after the antigen to normal male or female syngeneic animals before immunization with MRAG did not suppress the immune response to this antigen, whereas the transference of SpM cells from suppressed animals to animals previously immunized, depressed the delayed type hypersensitivity (DTH) response against MRAG (suppression of the expression) only in male rats. Similar results were obtained by transference of purified T cells. SpM cells did not suppress an established humoral immune response induced in male or female rats. The results suggest that non-adherent cells present in the spleen of male suppressed rats might be one of the responsible mechanisms for suppression of the efferent phase of the cellular autoimmune response to MRAG.

Analysis of Autoimmunity through Experimental Models of Thyroiditis and Allergic Encephalomyelitis

Publisher Summary This chapter presents the relationship between the normal state of self-tolerance and its abnormal corollary, autoimmunity. The several possible bases for loss of self-tolerance, including failure of immune regulation and abnormal presentation of potential self-antigens, are considered in terms of current understanding of cellular and humoral immune processes. A particularly thorough evaluation of suppressor cells and their possible role in self-tolerance and autoimmunity is presented. The pathogenic mechanisms that may be involved in autoimmune disease are examined in the light of two familiar experimental models, allergic encephalomyelitis and autoimmune thyroiditis. The pathogenic potential of cellular autoimmune responses in encephalomyelitis, on the one hand, and of autoantibody responses in thyroiditis, on the other, indicates the very different pathogeneses, which may operate in autoimmunity. The various mechanisms that are responsible for the loss of tolerance to self antigens can be divided into three general categories. First, abnormalities may occur in the regulatory mechanisms that control the normal immune response. Second, a component of self that was once sequestered and nonimmunogenic may become exposed and presented in an antigenic form to the immune system. Third, a normally tolerated self component may for some reason circumvent the prevailing regulatory mechanisms and activate one or more arms of a normal immune system. Numerous factors are involved in autoimmune diseases including genetic control at major histocompatibility complex (MHC) and non-MHC loci, immunologic regulatory mechanisms, self-nonself recognition, and logistics and/or nature of the target autoantigens.