Anti-acetylcholine receptor antibodies in primary biliary cirrhosis

Low concentrations of acetylcholine receptor antibodies were found in 16 out of 17 patients with primary biliary cirrhosis. Seven patients were treated or had been treated with penicillamine. Ten untreated patients had antibody levels corresponding to those found in the treated group. Our data support the presence of receptor antibodies of both IgG and IgM class.     

Experimental allergic orchitis in mice. I. A new model induced by immunization without adjuvants

Experimental allergic orchitis (EAO) was induced in cyclophosphamide (CY)-pretreated C3H/He mice by immunization with viable testicular cells (TC) without any adjuvants. The pathological changes such as hypospermatogenesis in the seminiferous tubules and mild cellular infiltration in the interstitium were observed in most mice thus treated. Delayed footpad reaction (DFR) against testicular antigen and anti-sperm antibody in sera were detected in those mice. This murine model of orchitis is new and simple in that no adjuvants are used for induction and can be useful in further studies on mechanisms of induction and maintenance of EAO.     

Anti-acetylcholine receptor antibodies decrease after thymectomy in patients with myasthenia gravis. Clinical correlations

Clinical course and changes in serum levels of antibodies to the acetylcholine receptor (a-AChR) were followed in 82 patients with myasthenia gravis during a period of 1-8 years after thymectomy. Decrease in a-AChR immediately after thymectomy was influenced by changes in a total IgG. Immunosuppressive medication affected serum a-AChR at all points of time. In a subgroup of 41 patients without thymoma who had no immunosuppressive drugs, there was a steady decrease in a-AChR concomitant with clinical improvement from 6 weeks after thymectomy.     

Anti-acetylcholine receptor antibodies in neonatal myasthenia gravis: heterogeneity and pathogenic significance

Precipitating, blocking and modulating anti-AChR antibodies and their capacity to recognize embryo or adult muscle were investigated in parallel in maternal and neonatal sera of fifty-two newborns and their myasthenic mothers. Twenty-four babies presented neonatal myasthenia gravis (NMG) with a common expression in twenty cases and foetal involvement in four cases. Occurrence of NMG was clearly related to levels of maternal precipitating, decamethonium blocking (DC blocking) and modulating antibodies (respectively P less than 0.001, P less than 0.02, P less than 0.01, Mann-Whitney test), these three parameters being interrelated. The only significant difference between mothers with severely affected babies and others with mild NMG newborns concerned DC blocking antibodies. Transfer fraction of DC blocking antibodies was significantly higher in NMG than in asymptomatic babies. Our data suggest that (1) the amount of anti-AChR antibodies, whatever the tested category, is involved in the pathogeny of NMG in a more direct manner than in adult MG where the correlation with their levels is poor, and (2) among antibodies, those with blocking effects could be preponderant for triggering NMG and be involved in the severity of the disease in the child.     

Anti-acetylcholine receptor idiotypes in myasthenia gravis analysed by rabbit anti-sera.

Anti-idiotype sera, raised in rabbits against anti-acetylcholine receptor (AChR) (idiotype) purified from the serum of three myasthenia gravis patients, inhibited binding of homologous idiotype to the AChR by up to 80%. The expression of idiotype in the three individuals changed very little over a period of several years, during which they showed a declining trend in overall anti-AChR antibody. Only one of the four anti-idiotype sera inhibited the binding of anti-AChR from a number of other patients. Our results indicate a consistency of idiotype expression within an individual, and fail to show substantial idiotype sharing between individuals.     

Foot-and-mouth disease virus-neutralizing antibodies induced in mice by anti-idiotypic antibodies.

A neutralizing monoclonal antibody (nmAb) to foot-and-mouth disease virus (FMDV) was used as antibody-1 (AB1) to induce anti-idiotypic antibodies (a-IdAb) in rabbits. The rabbit a-IdAb (AB2) were isolated on protein A-Sepharose, followed by cycles of separation on idiotype and isotype affinity columns. The specificity of the AB2 for the paratope of AB1 was determined by direct binding to AB1 in solid-phase radioimmunoassay (SP-RIA), and by competition RIA (C-RIA) with virus for binding to the AB1. The AB2, termed a-2PD11, was utilized to immunize six groups of female Swiss mice at weekly intervals with either one of three formulations, in doses of 50 micrograms or 5 micrograms, given in single subcutaneous (s.c.) spots. Anti-viral antibody (AB3) was first detected by RIA at the fifth week in the 50 micrograms/dose groups, and maximum levels were reached at the sixth week in the 50 and 5 micrograms/dose groups. The AB3 levels were at least three times higher for mice given 50 micrograms doses. In addition, the AB3 were also shown to neutralize FMDV infectivity in tissue culture and in a suckling mouse protection assay. Overall, mice exhibited variable responses to immunization with AB2. In a subsequent trial, mice received multispot s.c. and footpad injections of 50 micrograms of a-2PD11 coupled to keyhole limpet haemocyanin (KLH) on a weekly basis. In these mice, AB3 was detected earlier than in mice immunized with single s.c. injections. These results support the use of a-IdAb as potential surrogates of critical determinants for FMD vaccines.     

Autoimmunity induced by injection of virus-modified cell membrane antigens in syngeneic mice.

C3H/Bi mice developed autoantibodies after repeated inoculations of isolated membranes from primary tissue cultures of a syngeneic ascites lymphoma in which Newcastle disease virus had grown. This was in addition to the tumor transplantation resistance and cytotoxic antibodies previously demonstrated. The complement-fixing antibodies were completely removed from sera by adsorption with ascites tumor cells but only partially by normal mouse liver powder or C3H/Bi erythrocytes. With continued immunization, antibodies to deoxynucleoprotein and heterophile reagins also appeared. After several months, mice showing these serological reactions died with a wasting disease characterized by loss of lymphoid tissue and scarred, atrophied kidneys. No significant antibody response or autoimmune disease occurred in mice receiving membranes from uninfected syngeneic ascites lymphoma.     

Anti-acetylcholine receptor antibody related idiotypes in myasthenia gravis

Anti-acetylcholine receptor antibody associated idiotypes were defined by six murine monoclonal antibodies raised against purified receptor antibodies. Four of the monoclonal antibodies bound to idiotopes located within or close to the antigen binding site of the anti-receptor antibodies; the other two monoclonal antibodies were directed against framework determinants. These monoclonal antibodies recognized idiotopes present on immunoglobulins in 14-60% of patients presenting myasthenia gravis, indicating substantial idiotype sharing. These idiotopes were also found in patients with no detectable anti-receptor antibody activity in their serum. In all patients studied, the pattern of idiotypes fluctuated considerably during the course of the disease regardless of clinical symptoms. This suggests continuous modulation of the autoimmune process in myasthenia gravis.     

Gastritis in neonatal BALB/cCrSlc mice induced by immunization without adjuvant can be transferred to syngeneic nu/nu recipients

The popularly exploited murine neonatal thymectomy experimental autoimmune gastritis (nTx:EAG) model requires the animal to be in a state of lymphopenia. Here we report on a novel murine immunization (without adjuvant) model that can establish a lasting gastritis. We demonstrate that the immunization model (imm:EAG) results in a bona fide autoimmune disease and define the resulting pathology and serology observed and compare it with that reported for human autoimmune gastritis. Immune cells present in the stomachs of imm:EAG gastritic mice include CD8 T cells, CD11b and Gr1 (granulocytes/monocytes) and B cells. We detected circulating antibodies of immunoglobulin G1 (IgG1) subclass, with some IgG(2a) and IgG(2b) reactive to stomach membranes and the parietal cell proton pump. The class and subclass of autoreactive antibodies resulting from imm:EAG suggest a T helper 1 (Th1)/Th2 immune response. We establish that both self-reactive T and B cells from BALB/cCrSlc imm:EAG gastritic mice have the potential to induce a gastritis in BALB/c syngeneic nu/nu recipients. We conclude that this model is likely to be superior to the currently popularly exploited nTx:EAG and provide insight into and an understanding of the mechanisms of and remedies for autoimmunity in an intact immune system.     

Histological modifications of the lymph nodes in mice bearing syngeneic grafts of tumours induced by methylcholanthrene.

Light and electron microscopical studies demonstrate that regional but also non-regional lymph nodes of C57BL mice grafted by tumours, induced by methylcholanthrene, are able to elicit a complex immunological response of the cellular, as well as of the humoral types. No significant difference was found according to the growth rate and the immunogenicity of the six tumours investigated. The cellular immunization is predominant during the two first weeks. It is mainly characterized by the appearance in the paracortical area of numerous immunoblasts which are in close connexions with'dendritic' macrophages showing multiple long cytoplasmic expansions. During the same period of time, the reticulum cells become hyperplasic in the sinus. From the 15th day to the death of the animals, the cellular immunizaiton progressively regresses while a humoral immunity develops. It shows itself as an hypertrophy of the lymph follicles and an increase in the number of medullary cord plasma cells.     

Macrophage activation by adjuvants in aging mice

Peritoneal macrophages from young (3-8 mo) and aging (12-29 mo) mice of the C58, BALB/c, C3H/He, C57BI/6J, and B6D2F1 stains were compared for their capacity to become activated by various adjuvants in four assays. In chemiluminescence, activation by phorbol myristic acetate or zymosan of macrophages from aging mice of the C58, BALB/c, and C3H/He strains was increased approximately twofold greater than that of cells from young mice. A reversal of this was seen in the same three strains when measuring activation of phagocytosis by lipopolysaccharide, polyadenylate:polyuridylate (polyA:poly U), or muramyl dipeptide in that increased activity was induced readily in macrophages from young but not aging mice. Similarly, tumoricidal activity of macrophages from young but not aging mice was stimulated 6.0- and 4.4-fold by lipopolysaccharide and poly A:poly U, respectively, in the C58 strain (the only strain studied). Activation by lipopolysaccharide and poly A:poly U of the hexose monophosphate shunt in macrophages from the C58 and C3H/He strains also was significant in young but not aging mice, whereas it occurred in both age groups of the BALB/c and C57B1/6J mice. A reversal of response patterns was observed between aging female virgin and breeder C58 mice in the chemiluminescence and hexose monophosphate shunt assays in that the breeding mice mimicked the young virgin mice.     

Self reactive delayed type hypersensitivity (DTH) induced in mice by syngeneic lymphoblasts

Normal and x-irradiated A mice injected with syngeneic concanavalin A (Con A)-induced lymphoblasts revealed after challenge with syngeneic lipopolysaccharide (LPS)-induced lymphoblasts delayed type hypersensitivity (DTH) measured both by footpad swelling and by ¹²⁵IudR accumulation. Mice injected with allogeneic Con A-induced lymphoblasts and challenged with syngeneic LPS-induced lymphoblasts or vice versa, also generated an appreciable DTH response. In contrast, Con A-induced blast cells of human origin (xenogeneic cells) generated a considerably less effective DTH. The DTH response was more profound and consistent in x-irradiated mice, suggesting that irradiation sensitive cells control this response. The syngeneic DTH response was efficiently transferred to naive recipients with Thy-1⁺, nylon wool passed cells. The establishment of the DTH activity was associated with the lymphoblasts own (differentiation?) antigens and not with contaminants attached to the cells, such as Con A or fetal calf serum. The results were compared with similar results reported by other groups and the biological significance of all findings was evaluated.     

Induction of delayed hypersensitivity to protein antigens in mice without Freund adjuvants

Three ways for inducing tuberculin-type delayed hypersensitivity (DH) in mice to purified protein antigens without Freund adjuvant are described. Four strains of mice compared for susceptibility to sensitization with several antigens ranked SJL > CF-1 > CAF₁ = C57B1. Females were more easily sensitized than males. The first way of sensitizing without Freund adjuvant was simply to inject antigen intradermally in saline, but it could be used only with the potent antigen methylated human serum albumin (HSA). Six-mercaptopurine injections during the first 5 days of sensitization enhanced such sensitization in CF-1 but inhibited it in CAF₁ mice. The second way sensitized with a weaker antigen, chicken conalbumin (CA), and thus is more versatile. It consisted of injecting a saline solution of antigen into a 24-hr strong DH dermal reaction to an unrelated antigen (dextran). The third way was simplest and best: Freund adjuvant was replaced with aqueous Evans blue dye. Thus, distilled water solutions of antigen (CA or chicken ovalbumin) and dye injected subcutaneously induced DH indistinguishable from that induced with the same antigens in Freund adjuvant. Neither antigen in distilled water alone sensitized. The dye also intensified Arthus sensitization. This diazo dye therefore may be a practical, harmless water-soluble substitute for Freund adjuvant for inducing DH or cell-mediated immunity and for intensifying Arthus sensitization.     

Induction and suppression of anti-antibodies to syngeneic T cell-binding antibodies in mice

Considerable effort is being invested in antibody gene technologies for production of species-adapted anti-T cell antibodies which can overcome formation of neutralizing anti-antibodies (anti-Ab). By establishing a mouse model for the generation of syngeneic anti-T cell MoAb, we addressed the question of whether ideally species-adapted T cell-binding antibodies can prime mice to produce anti-Ab. Two anti-Thy-1.2 MoAbs of IgG2a (MmTC) or IgM (MmTC-IgM) isotype were generated in congenic C57Bl/6-Thy-1.1 mice. Three injections of MmTC in C57Bl/6-Thy-1.2 or (C57Bl/6-Thy-1.2×C57Bl/6-Thy-1.1)F₁ hybrids where they act as syngeneic anti-T cell MoAbs induced low anti-Ab. When MmTC was injected as Igh-mismatched antibody in CBA/J mice, high titre anti-MmTC antibodies were measured and fully mismatched skin allografts rejected within 26 days. MmTC injected twice weekly in syngeneic C57Bl/6 mice induced low anti-MmTC and prolonged graft survival up to day 117. In contrast, retreatment induced anti-MmTC with graft rejection within 32 days. Thus, upon retreatment, the immunosuppressive effects of MmTC were inhibited to a similar extent as that seen after antibody treatment in Igh-mismatched mice. However, a recently analysed immunological principle to suppress anti-Ab against T cell binding allo- or xenoantibodies by preinjection of T cell-depleting antibody with species differences in heavy chains also suppressed syngeneic anti-Ab after MmTC retreatment. This effect was accompanied by prolonged graft survival. Thus, our data indicate that inhibitory anti-Ab must be considered in humans even when treated with fully species-adapted anti-T cell MoAb, but may be suppressed by preinjection of a Fc region-mismatched anti-T cell antibody.     

Specificity of anti-DNA antibodies induced in normal mice by immunization with bacterial DNA.

To determine the specificity of anti-DNA antibodies induced in normal mice by immunization with bacterial DNA, sera from BALB/c mice immunized with single-stranded DNA from Escherichia coli (EC) were tested for binding to a panel of synthetic DNA and RNA homopolymers as well as duplexes. Results of these studies indicate that sera from EC DNA immunized mice preferentially bind certain DNA and RNA homopolymers as well as DNA duplexes. Furthermore, the specificity of the antibodies from immunized mice resembled those of sera from autoimmune MRL-lpr/lpr mice in terms of the synthetic antigens recognized, although some differences were noted in the magnitude of the response to individual duplexes. These results suggest that anti-DNA antibodies induced by bacterial DNA bind to DNA structures dependent on both the base and the sugar phosphate moieties of the nucleic acid antigen and may resemble some anti-DNA antibodies expressed in spontaneous autoimmune disease in these binding properties.     

Development of syngeneic monoclonal anti-idiotype antibodies to mouse monoclonal anti-asialoglycoprotein receptor antibody

Anti-idiotype antibodies (Ab2) play an important role in the homeostasis of immune responses and are related to the development and the disease activity of certain autoimmune diseases. The asialoglycoprotein receptor (ASGPR) is considered one of the target antigens in the pathogenesis of autoimmune chronic active hepatitis (AIH). We previously developed a mouse monoclonal antibody (clone 8D7) which recognizes rat and human ASGPR. In this study, to help investigate the anti-ASGPR antibody-anti-idiotype antibody network in patients with AIH, we developed a syngeneic mouse monoclonal Ab2 to the 8D7 anti-ASGPR antibody (Ab1). One clone, designated as 3C8, tested positive for specific reactivity to 8D7-Ab1 and did not bind to other irrelevant immunoglobulins. By competitive inhibition assays, the binding of 8D7-Ab1 to liver membrane extracts, i.e., the crude antigen preparation, was inhibited by 3C8-Ab2 in a dose-dependent manner, and the binding of 8D7-Ab1 to 3C8-Ab2 was inhibited by the liver membrane extracts. In the immunohistochemical analysis, 3C8-Ab2 blocked the specific staining of sinusoidal margins of rat hepatocytes by 8D7-Ab1. These results suggest that 3C8 anti-idiotype antibody recognizes the specific idiotypic determinants within the antigen-binding site of 8D7-Ab1.     

Postinflammation stage of autoimmune orchitis induced by immunization with syngeneic testicular germ cells alone in mice

We previously established an immunological infertility model, experimental autoimmune orchitis (EAO), which can be induced by two subcutaneous injections of viable syngeneic testicular germ cells on days 0 and 14 in mice without using any adjuvant. In this EAO model, CD4+ T-cell-dependent lymphocytic infiltration and immune deposits were found with spermatogenic disturbance on day 120. However, the late stage of EAO (= postactive inflammation stage on day 365) has not yet been investigated. Therefore, we investigated the histopathological characteristics of the late stage. The results revealed that the lymphocytic infiltration finally resolved; however, the seminiferous epithelium persistently showed maturation arrest and the Sertoli cell-only feature. In the seminiferous tubules showing maturation arrest, both proliferation and apoptosis of germ cells had occurred simultaneously. It was also noted that there were deposits of immunoglobulin G and the third component of complement on the thickened basement membrane of seminiferous tubules in the late stage of EAO. These results indicate that histopathology after active inflammation in EAO comprises persistent damage to the seminiferous epithelium and may resemble the histopathology of “idiopathic disturbance of spermatogenesis” in man.     

Murine tumor cells expressing the gene for the human interferon alpha beta receptor elicit antibodies in syngeneic mice to the active form of the receptor

The cellular receptor for the human alpha and beta interferons (IFN) was expressed, by gene transfer, in a murine hepatoma-derived cell line, BTG 9A. Injected subcutaneously into the syngeneic mouse (C57BL/6), the parental and the transfected cells grew and formed tumors which later regressed. More than half the mice bearing tumors derived from cells expressing the receptor, developed IgG antibodies capable of blocking the activity, on human cells, of human recombinant IFN-alpha B, -alpha A, -alpha D and of natural human IFN-beta, but not of recombinant IFN-gamma. Cross-reactivity of human IFN-alpha on murine and bovine cells was unaffected by these antibodies. The binding of human IFN-alpha to solubilized receptors from human lymphoid cell lines was also blocked and complexes of radiolabeled recombinant IFN-alpha A or IFN-alpha B, chemically cross-linked to their human receptor could be immunoprecipitated by the antisera. IFN alpha beta receptor protein, purified by electrophoresis in sodium dodecylsulfate, was not recognized. We conclude that the antibodies are directed against the forms of the IFN alpha beta receptor actually expressed on the membrane.     

Autoimmunity induced by syngeneic splenocyte membranes carrying irreversibly adsorbed paramyxovirus.

Newcastle disease virus was adsorbed to a membrane fraction prepared from splenocytes, and the resulting preparation was injected into syngeneic C3H mice. Complement fixing and cytotoxic antibodies reactive with syngeneic tissue and intact cells developed, and some mice died with autoimmune disease characterized by wasting, severe kidney damage, and loss of lymphoid tissue as described previously for animals receiving the membrane fraction of a syngeneic lymphoma in which Newcastle disease virus had grown. Similar experiments were done with L929 mouse fibroblasts and allogeneic spleen membrane fractions. With syngeneic spleen tissue and L929 fibroblasts, serological evidence of autoimmunity appeared after several injections, but deaths from autoimmunity were considerably delayed unless Freund's complete adjuvant was given with the antigen. The results suggest that antigen modification occurs after adsorption of the paramyxovirus to normal tissue as well as lymphoma cell membranes.     

Pathogenic autoimmunity to affinity-purified mouse acetylcholine receptor induced without adjuvant in BALB/c mice

Myasthenia gravis (MG) and experimental autoimmune myasthenia gravis (EAMG) are antibody-mediated disorders in which anti-acetylcholine receptor (anti-AChR) antibodies cause loss of muscle AChR and subsequent weakness. Many species are susceptible to induction of EAMG with purified xenogeneic AChR in adjuvant, but injection of Torpedo AChR without adjuvants can also induce evidence of EAMG. To see whether pathogenic autoimmunity could be induced in mice by isolated mouse AChR we injected BALB/c mice with several doses (1 pmole; about 0.1 ug) of affinity-purified AChR (from the BC3H1 cell line but thought to be identical with denervated mouse muscle) intraperitoneally, without adjuvant, over a period of 10-22 weeks. Some of the mice became ill and died. High levels of serum anti-mouse AChR, directed mainly towards the main immunogenic region, were found and, in the survivors, correlated with loss of muscle AChR. Thus BALB/c mice can mount an autoimmune response to minute amounts of mouse AChR, without the use of adjuvants, and this response is very similar to that found in MG. This novel finding has implications regarding the etiology of the human disease.