The mode of action of treatment by IgG of haemolytic anaemia induced by an anti-erythrocyte monoclonal antibody

Tolerization of pathogenic antigens is one of the experimental strategies that has been proposed to prevent autoimmune disease. We have investigated here whether neonatal intraperitoneal infection of Lewis rats with Mycobacterium bovis-BCG has any effect on the expression of adjuvant arthritis (AA), an autoimmune disease that is produced by immunization of the rats with dead mycobacteria in mineral oil (i.e. Freund's complete adjuvant (FCA)). We found that neonatal infection with 10⁸ viable BCG bacilli rendered all Lewis rats resistant to the expression of AA after FCA immunization. This BCG-induced protection from reactive arthritis was not seen in Lewis rats infected with smaller inocula (10⁶ BCG bacilli) or if the infection was performed after the neonatal period (e.g. at 3 weeks of age). Neonatal administration of 65-kD mycobacterial heat shock protein (hsp65, a key antigen in the etiopathogenesis of AA) failed to protect Lewis rats from AA; injection of lactoferrin (an autoantigen that may be involved in the physiopathology of autoimmune arthritis) to newborn Lewis rats decreased the severity of AA observed after FCA immunization of the animals. Western blotting revealed that Lewis rats that had acquired resistance to AA also showed changes in their repertoire of antibody specificities; among these alterations was decreased anti-hsp65 reactivity. We conclude that neonatal infection with BCG, but not hsp65 injection, renders Lewis rats resistant to AA and that the phenomenon is associated with change in the repertoire of specificities of circulating antibodies.     

Diversification of response to hsp65 during the course of autoimmune arthritis is regulatory rather than pathogenic

Summary: Determinant spreading has been implicated in the pathogenesis of certain autoimmune diseases in animal models. We have observed that during the course of adjuvant arthritis (AA) in the Lewis rat, there is 'diversification' of response to the bacterial 65-kDa heat shock protein (Bhsp65) towards its carboxy-terminal determinants (BCTD). Strikingly, pretreatment of naive Lewis rats with BCTD affords significant protection from AA. Our preliminary studies indicate that the diversification of response to BCTD in the Lewis rat is probably triggered in vivo by the induction and enhanced processing of self(rat) hsp65. Thus, the self hsp65-directed T-cell responses appear to be involved in mediating natural remission from acute inflammatory arthritis induced by a foreign antigen, Myco-bacterium tuberculosis. This the first report describing that the new T-cell specificities arising during the course of an autoimmune disease are regulatory/protective rather than pathogenic. Moreover, our results suggest that a final common mechanism involving BCTD might be recruited by other rac strains which either are resistant to AA (WKY rats) or whose susceptibility to AA is modulated significantly by microbial flora (Fisher rats). The results of this study would contribute significantly to understanding of the pathogenesis of human rheumatoid arthritis, and in devising new therapeutic strategies for this disease.     

Differential rat T cell recognition of cathepsin D-released fragments of mycobacterial 65 kDa heat-shock protein after immunization with either the recombinant protein or whole mycobacteria

T cells specific for the mycobacterial 65 kDa heat-shock protein(hsp65) play a pivotal role in the development of adjuvant arthritis(AA) in Lewis rats. Upon adoptive transfer, CD4⁺ T cells recognizinga particular hsp65 epitope trigger the onset of disease. Activationof hsp65-reactlve T cells can be achieved by immunization withheat-killed mycobacteria in mineral oil—complete Freund'sadjuvant (CFA)—or with purified recombinant hsp65. Arthritis,however, will only develop after immunization with CFA. In fact,prelmmunlzatlon with hsp65 protects against any subsequent attemptto induce AA. In this study, we examined polyclonal lymph nodecell responses in Lewis rats, Immunized with either CFA or purifiedrecombinant hsp65 in incomplete Freund's adjuvant, to a setof hsp65 fragments generated by a mild digestion with cathepsinD. Prollferatlve responses to several hsp65 fragments variedwith the type of antigen used for immunization. A cathepsinD-released fragment, Identified as residues 376–408, preferentiallytriggered proliferation of rat T cells after hsp65 Immunization.Prelmmunlzatlon of Lewis rats with this peptlde delayed theonset and reduced the severity of AA. Prelmmunlzatlon with anotherfragment which was preferentially recognized after CFA immunization,representing residues 40–60, did not have such a protectiveeffect. Our findings suggest the presence of mycobacterial hsp65determinants that selectively trigger AA-regulatlng T cellsand illustrate that cathepsin D may be used as an experimentaltool to generate such determinants.     

Modulation of adjuvant arthritis in Lewis rats by recombinant vaccinia virus expressing the human 60-kilodalton heat shock protein.

The immune response to the mycobacterial 65-kDa heat shock protein (hsp65) is considered an important event in the induction of adjuvant arthritis (AA) in rats; this induction probably occurs through a molecular mimicry mechanism involving cross-reactivity against the rat homolog hsp60. To analyze the role of mammalian molecule hsp60 in arthritis, we generated a recombinant vaccinia virus (hsp60-VV) carrying the human hsp60 gene inserted into the thymidine kinase locus under the control of the 7.5k vaccinia virus promoter. Human hsp60 is almost identical to its rat homolog (97.4% linear amino acid homology) and shares about 50% of amino acid positions with Mycobacterium tuberculosis hsp65. The latter supposedly carries a critical epitope for AA induction that is not present in human hsp60. Infections with hsp60-VV of monkey cell cultures led to the expression of the human hsp60 molecule, as evidenced by immunoblotting analysis with specific monoclonal antibodies. Also, Lewis rats infected with hsp60-VV produced specific antibodies, demonstrating the in vivo expression of human hsp60 in the infected animals. Therefore, we used hsp60-VV to analyze whether the delivery of hsp60 could affect the induction of AA in Lewis rats. hsp60-VV clearly reduced and retarded arthritic symptoms when administered to rats at day 7 after AA induction. In contrast, inoculation of rats with a control recombinant vaccinia virus did not affect the course of the disease. The improvement in AA with hsp60-VV administration was associated with a specific immune response, as determined by the presence of antibodies to hsp60 in the sera and the proliferation induced by hsp60 of T cells from popliteal lymph nodes. These results support a critical role for immunity to heat shock proteins in AA. Since the protective construct is virtually identical to rat homolog hsp60, we conclude that immunity directed to conserved areas of this family of proteins is directly involved in the pathogenesis of AA.     

Inflammation activates self hsp60-specific T cells

Injection of incomplete Freund's adjuvant (IFA) into the footpads of BALB/c mice induced an acute inflammation. Draining popliteal lymph nodes showed major histocompatibility complex (MHC) class II-restricted proliferation when challenged in vitro with recombinant Mycobacterium bovis 65-kDa heat shock protein (hsp65). αβ Tcell receptor-positive, CD4⁺, hsp65-specific T cell lines and clones were generated from these lymph nodes, and 87% of clones responded to a P galactosidase fusion protein containing residues 238–573 of human hsp60. Seventy percent of these hsp60-responsive clones also responded to a synthetic peptide corresponding to residues 412–423 of the mouse hsp60. This peptide also induced significant responses in IFA-primed lymph node cells but not in lymphoid cells from unimmunized mice. These results demonstrate that T cells specific for epitopes in self hsp60 are activated during inflammatory responses induced in the absence of exogenous bacterial hsp65. The findings of this study may provide a basis for understanding the often reported isolation of mycobacterial hsp65-responsive T cells from inflammatory sites of arthritis patients, and the protective effects of preimmunization with hsp65 in experimental models of arthritis.     

Natural antibodies to 65 kD mycobacterial heat shock protein in rats do not correlate with susceptibility for Mycobacterium tuberculosis induced adjuvant arthritis

Natural antibodies to 65 kD heat shock protein (hsp65) of Mycobacterium bovis were found in the sera of Lewis rats. The levels of these natural hsp65 antibodies differed substantially between the individual rats. Each rat was subsequently tested for its susceptibility to develop arthritis following injection of M. tuberculosis in incomplete Freund adjuvant. It was found that the incidence and severity of the induced arthritis did not differ between groups of Lewis rats with relatively high and relatively low natural antibody levels to hsp65. Inoculation of rats without natural antibodies to hsp65 with intestinal contents did not induce hsp65 antibodies, although the rats were able to respond to the antigen.     

T-cell vaccination in experimental myasthenia gravis: A double-edged sword

Immunization with antigen-specific T cells has been used successfully in the treatment of several T cell-mediated experimental autoimmune diseases, including experimental allergic encephalomyelitis, thyroiditis, and adjuvant arthritis. The aim of this study was to determine whether T-cell vaccination could be used to down-regulate specifically the antibody response to AChR in experimental autoimmune myasthenia gravis (EAMG), an antibody-mediated disorder. We produced T cells specific for the acetylcholine receptor (AChR) by immunizing Lewis rats with torpedo AChR, harvesting the regional lymph node cells, and restimulating them in vitro with AChR. This cell population was expanded with IL2. The cells were then activated with concanavalin A (Con-A) and exposed to high hydrostatic pressure to augment their immunogenicity. We found that rats vaccinated with these cells did not manifest decreased antibody titers to AChR, when challenged. In fact, the antibody response to AChR was consistently potentiated by the vaccine treatment. This result could not be attributed to antigen carryover by the vaccinating cells or to induction of anti-idiotypic antibodies. Despite these results showing overall enhancement of the AChR antibody response, we found evidence of AChR-specific suppressor cells in the spleens of the vaccinated animals. Our observations indicate that T-cell vaccination can elicit both a positive immune response and a suppressive response in the same animal. If the T-cell vaccination strategy is to be useful for the treatment of MG, methods for amplifying the suppressive effect will need to be developed.     

An IgG thymolytic autoantibody in rats which has specificity for a subpopulation of T cells.

A cytotoxic anti-thymocyte IgG auto-antibody is present in Lewis rats which, in the presence of autologous complement, destroys (in vitro) 12-28 per cent of isologous or autologous thymocytes, a smaller number of lymph node cells and splenocytes, but not bone marrow or circulating lymphocytes. The labile cells in the thymus represent a finite subpopulation which is autologous antithymocyte antibody (ATS) sensitive and steroid resistant. The presence of the autoantibody is randomly distributed in outbred animals whereas in inbred Lewis rats, a strain in which the induction of some autoimmune reactions is under genetic control, the antibody is always present. In this strain, the susceptible T cells and the quantity of circulating autoantibody is significantly depressed during the productive phase of a T-cell mediated disease (adjuvant polyarthritis) and returns to normal after the disease becomes stabilized. There is a direct relationship between the amount of susceptible cells in the thymus and the amount of antibody in circulation, suggesting that the antibody could serve as a marker for a specific subpopulation of thymocytes which may have a regulatory influence on T-cell reactivity.     

The Dynamics of Articular Leukocyte Trafficking and the Immune Response to Self Heat-Shock Protein 65 Influence Arthritis Susceptibility

INTRODUCTION: Adjuvant arthritis (AA) shares several features with human rheumatoid arthritis, and it can be induced in the Lewis (LEW) rat but not the Wistar Kyoto (WKY) rat (both RT.1(l)) by immunization with heat-killed Mycobacterium tuberculosis (Mtb). We set out to unravel the mechanisms underlying the differential susceptibility to AA of these MHC-compatible rat strains. MATERIALS AND METHODS: We compared the levels of T-cell proliferative and cytokine response to the immunoregulatory self (rat) hsp65 (Rhsp65) after an arthritogenic (Mtb) challenge and the kinetics of migration of adoptively transferred, (111)Indium-labeled, Mtb-primed leukocytes into the hind paw joints of recipient rats. RESULTS AND DISCUSSION: The WKY rats raised a significantly higher level of T-cell proliferative response coupled with a temporally opposite cytokine profile against the disease-regulating Rhsp65 compared to that of LEW rats. Moreover, the arthritogenic leukocytes accumulated into the joints of WKY rats at significantly lower numbers than that in LEW rats. CONCLUSIONS: These results offer novel insights into the immune events influencing the pathogenesis of autoimmune arthritis.     

Arthritis transferred by cells derived from pre-inflammatory rat synovium.

Different cell populations isolated from rats during the period of latency of adjuvant arthritis were injected into the bloodstream of naive rats to test their ability to transfer articular disorders. Synovium-derived cells (synoviocytes) were able to induce arthritis in 3 out of 4 recipient animals, whereas peripheral blood leukocytes, peritoneal exudate macrophages, lymph node cells, synoviocyte lysates and synoviocytes from control animals were not able to do so. This model of cellular transferred arthritis is associated with antibody titres to hsp65 in rat sera. Our findings suggest a crucial role for synovial cells in the pathogenesis of adjuvant disease, which might be linked to their function as accessory cells.     

T cell reactivity to an epitope of the mycobacterial 65-kDa heat-shock protein (hsp 65) corresponds with arthritis susceptibility in rats and is regulated by hsp 65-specific cellular responses.

Adjuvant arthritis (AA) can be induced in genetically susceptible rats by immunization with heat-killed mycobacteria suspended in mineral oil. From our analysis of arthritogenic T cell clone A2b, obtained from an arthritic Lewis rat and specific for the 180-188 epitope of mycobacterial 65-kDa heat-shock protein (hsp 65), the possible origin of AA was explained by the existence of a molecular mimicry of the 180-188 epitope with a cartilage-associated self antigen. We now have shown that Lewis rats respond to the 180-188 epitope after Mycobacterium tuberculosis immunization and that arthritis-resistant Fisher and (Lewis x Fisher)F1 rats, although major histocompatibility complex class II identical with Lewis, do not respond to this epitope. However, in rare cases of arthritis in Fisher rats, responses to the epitope were seen. We obtained no evidence for a defect at the level of antigen processing and presentation or for suppression in Fisher rats. Thus, non-responsiveness in Fisher rats was likely due to a difference at the level of the T cell repertoire. Previously, we have reported that pretreatment with hsp 65 in experimental arthritis, and not only in AA, caused resistance to arthritis induction. We now present evidence that immunization with hsp 65 or in vitro stimulation with hsp 65 may lead to inhibition of responses specific for epitope 180-188. Thus the hsp 65-induced resistance to arthritis is probably caused by the induction of regulatory control specifically targeted at the 180-188 epitope. Especially in rats that tend to focus their responses on the critical 180-188 sequence, such as Lewis, regulation seems to develop following immunization with hsp 65. Since recent evidence suggests that hsp 65 and also the 180-188 epitope have a role in human arthritic conditions, the present findings are expected to contribute to further experimentation directed at exploiting hsp 65 or its epitopes for the development of new therapeutical approaches in humans.     

Vaccination against experimental autoimmune encephalomyelitis using a subencephalitogenic dose of autoimmune effector T cells. (2). Induction of a protective anti-idiotypic response

We previously reported that a subencephalitogenic dose (10(4) of activated anti-BP Z1a T cells rendered Lewis rats significantly resistant to EAE induced either actively or adoptively. This resistance was specific to EAE and persisted for over 4 months. The experiments reported in this paper were done to investigate the mechanisms of this resistance. We found that the state of vaccination was marked by a decrease in the in vitro proliferation and in vivo DTH responses to BP. Resistance could be transferred to recipient rats with the thymus or spleen cells of donor vaccinated rats. Vaccination led to the appearance of proliferative and DTH responses that were specifically directed to the Z1a T cells. The kinetics and compartmentalization of this anti-idiotypic responsiveness was studied by vaccinating rats in the hind footpads and monitoring the proliferative reactivity of the draining popliteal lymph node (PLN) and distal cervical lymph node (CLN) cells at various times. We found that the anti-idiotypic reactivity was confined to the PLN on days 5-6 and thereafter became systemic. Excision of the PLN on day 6, but not on days 3 or 11, robbed the rats of their acquired resistance to EAE. In contrast, the PLN cells of the vaccinated rats transferred resistance to naive donors. Thus, the lymphoid population containing cell-mediated anti-idiotypic responsiveness served as a vehicle of resistance. These results suggest that anti-idiotypic T-cell immunity to autoimmune effector T cells is involved in the resistance to EAE induced by T-cell vaccination.     

Arthritis induced in rats with adjuvant oil is a genetically restricted, alpha beta T-cell dependent autoimmune disease.

Adjuvant arthritis in rats is usually induced by injection of mycobacterium tubercle cell walls suspended in various adjuvant oils such as Freund's incomplete adjuvant (FIA) or pristane. We have recently shown that injection of adjuvant oils without inclusion of mycobacterium tubercle cell walls triggers arthritis [oil adjuvant-induced arthritis (OIA)] in the DA rat strain. The OIA is a genetically restricted disease since only DA rats are susceptible while Lewis, DA-fostered Lewis and F1 (Lew x DA) rats are relatively resistant. Activated alpha beta T cells infiltrate the affected joints of adjuvant oil-injected DA rats and treatment with monoclonal antibodies to the alpha beta T-cell receptor abrogates development of arthritis. These findings show that alpha beta T-cell activation is a critical event in the development of OIA.     

Role of the Bowel Flora for Development of Immunity to hsp 65 and Arthritis in Three Experimental Models

An infectious aetiology in rheumatoid arthritis (RA) has for long been suggested, although no conclusive evidence for this is at present available. Lately a large interest has been devoted to the involvement of heat shock proteins (hsps) in autoimmune disorders due to their conserved structure and immunogenic properties. Immunity to hsps has been observed both in human autoimmune conditions and in experimental models of autoimmune disease. We have studied the role of the bacterial flora and hsp immunity in the arthritic response in three experimental models of arthritis; type II collagen arthritis (CIA), adjuvant arthritis (AA) and oil induced arthritis (OIA); by using germ free and conventional DA rats.
A high incidence of severe arthritis developed in all the models evaluated irrespectively of whether the animals were in the conventional or germ free state. This confirms earlier results which show a minor effect of the bacterial flora in CIA and AA in high responder strains. These results also show that a severe OIA can develop in germ free animals. Despite the severe arthritic response induced, no serum antibody levels to hsp 65 could be detected in the germ free animals, which was in contrast to the conventional animals where a positive anti-hsp 65 serum response was seen in 35–80% of the animals with CIA, AA or OIA.
These results show that development of a humoral response to hsp 65 in these models of arthritis is dependent on the presence of a bacterial flora. Further, the lack of humoral immunity in germ free animals despite a severe arthritic response indicates that humoral immunity to hsp 65 is not involved in development of disease in these three models of experimental arthritis.     

Autoreactive CD4- CD8- alpha beta T cells to vaccinate adjuvant arthritis.

Studies suggested that experimental autoimmune diseases can effectively be prevented and treated by application of normal autoreactive T cells or autoreactive T cells in an attenuated form. In this study, several autoreactive CD4- CD8- T-cell clones (A2, A6, and A13 cells) were isolated for the first time from the draining lymph nodes of Lewis rats with adjuvant arthritis (AA). Surprisingly, intraperitoneal inoculation with A13 cells, but not A2 or A6 cells protected rats from AA both clinically and histologically. It was demonstrated that A13 cells were CD4- CD8- alpha beta T cells, and showed proliferative responses to irradiated syngeneic spleen cells (antigen-presenting cells; APC). Interestingly, A13 cells proliferated against concanavalin A (Con A) and staphylococcal enterotoxin B (SEB), but did not show any proliferation to Mycobacterium tuberculosis (Mt), or its 65 000 MW heat-shock protein (HSP). Rats protected from AA by inoculation with A13 cells showed a specific anti-idiotypic delayed-type hypersensitivity reaction compared with other autoreactive T cells (A2 or A6 cells). These findings demonstrate that AA can be suppressed by autoreactive CD4- CD8- alpha beta T cells, and these cells may be used as therapeutic agents in experimental autoimmunity.     

Dose-dependent mechanisms relate to nasal tolerance induction and protection against experimental autoimmune encephalomyelitis in Lewis rats.

Nasal administration of soluble antigens is an exciting means of specifically down-regulating pathogenic T-cell reactivities in autoimmune diseases. The mechanisms by which nasal administration of soluble antigens suppresses autoimmunity are poorly understood. To define further the principles of nasal tolerance induction, we studied the effects of nasal administration of myelin basic protein (MBP) on experimental autoimmune encephalomyelitis (EAE) in the Lewis rat. EAE is a CD4+ T-cell-mediated animal model for human multiple sclerosis. Nasal administration of guinea-pig (gp)-MBP at a dose as low as 30 micrograms/rat can completely prevent gp-MBP-induced EAE, whereas nasal administration of bovine (b)-MBP is not effective even at a much higher dosage. Cellular immune responses, as reflected by T-cell proliferation and interferon-gamma (IFN-gamma)-ELISPOT, were suppressed in rats receiving the two different doses (30 and 600 micrograms/rat) of gp-MBP, but not after administration of b-MBP. Rats tolerized with both doses of gp-MBP had also abrogated MBP-induced IFN-gamma mRNA expression in popliteal and inguinal lymph node mononuclear cells compared with rats receiving phosphate-buffered saline nasally. However, adoptive transfer revealed that only spleen mononuclear cells from rats pretreated with a low dose, but not from those pretreated with a high dose, of gp-MBP transferred protection to actively induced EAE. Low-dose (30 micrograms/rat) gp-MBP-tolerized rats also had high numbers of interleukin-4 (IL-4) mRNA-expressing lymph node cells, while high-dose (600 micrograms/rat) gp-MBP-tolerized rats had low numbers of IL-4 mRNA-expressing lymph node cells. Our data suggest an exquisite specificity of nasal tolerance. Dose-dependent mechanisms also relate to nasal tolerance induction and protection against EAE in the Lewis rat.     

The 65-kDa heat-shock protein in the pathogenesis, prevention and therapy of autoimmune arthritis and diabetes mellitus in rats and mice

Conclusions hsp are molecules which are highly conserved from procaryotes to eukaryotes. At a first glance the immune system should treat these molecules as self. However, strong immune reactions to bacterial hsp are observed during infection in mammals.hsp65 plays a role in several autoimmune diseases in animal models. In AA in Lewis rats the involvement of hsp65 has been revealed by T cell clones which induce disease in naive recipients, or by T cell vaccination experiments. T cell clones which show in vivo activity have been used as tools in vitro to define epitopes involved in the disease process. In this manner mycobacterial hsp65 and its epitope peptide 180–188 were deduced for AA in Lewis rats. Similarily the epitope p277 was defined for diabetes in NOD mice.The role of hsp65 in several other autoimmune diseases was seen when animals were pretreated with hsp65 and found to be protected from subsequent induction of autoimmune disease. From the involvement of hsp65 in several different autoimmune diseases, it would appear that hsp65 is somehow a key factor in natural autoimmunity. At a fist glance this is surprising since mycobacterial hsp65 shows 50% amino acid homology with human hsp65, in other words it is half-self.Peptide epitopes, peptide 180–188 in AA in Lewis rats and p277 in IDDM in NOD mice, have been used for peptide vaccination, which represents another possibility for prevention of autoimmune disease. The immunological mechanism which leads to resistance from autoimmune disease involves hsp65 immunity and appears not to be associated with tolerance or non-responsiveness to hsp65, but seems to be due rather to modulation of naturally existing networks of idiotype-anti-idiotype T cells organized around hsp65 as the target antigen.     

Modulation of experimental autoimmunity: treatment of adjuvant arthritis by immunization with a recombinant vaccinia virus.

Live recombinant vaccinia viruses, expressing antigens from pathogenic microorganisms, are studied for their use as vaccines designed for the protection against infectious diseases. Infections with these vaccinia virus recombinants, expressing proteins or epitopes from viruses, parasites, or bacteria, have resulted in the development of specific neutralizing antibodies or cytotoxic T lymphocytes. Here, we describe the generation of a recombinant vaccinia virus expressing the mycobacterial 65-kDa heat shock protein (HSP65). A vaccinia recombinant virus was constructed by placing the gene for the Mycobacterium bovis BCG HSP65 under control of a vaccinia virus promoter and inserting this mycobacterial gene in the thymidine kinase locus of the vaccinia virus genome. Mycobacterial HSP65 is a critical antigen in the autoimmune model of adjuvant arthritis induced in Lewis rats by the immunization with Mycobacterium tuberculosis. We report the induction of immunity directed to this mycobacterial HSP65 by testing for the presence of specific antibodies and T-cell proliferation. Furthermore, induction of such immunity resulted in a reduction of arthritis severity when given to rats before or, even more interestingly, during development of arthritis. Disease reduction was not found after administration of HSP65 in the absence of vaccinia virus as a vector when given during arthritis development. Therefore, recombinant vaccinia virus may offer new prospectives for specific intervention in autoimmunity.     

Immunoglobulins from rats that are resistant to adjuvant arthritis suppress the disease in arthritis-susceptible rats

The therapeutic effect of high doses of polyclonal immunoglobulins has been well established in various B cell-associated autoimmune diseases. In the present work we have examined the effect of low doses of immunoglobulins in adjuvant arthritis, a T cell-associated disease in the Lewis rat. Lewis rats were treated with purified rat immunoglobulins as well as their Fc and F(ab′)₂ fragments and their protective effect on adjuvant arthritis was evaluated. We found that early as well as late treatment with low doses of rat immunoglobulins induced refractoriness to disease induction. The effect was found to be carried out by the F(ab′)₂ part of the immunoglobulins and could be adsorbed by affinity purification on Mycobacterium tuberculosis. The protective antibodies were present in Fisher and BN rats that are resistant to adjuvant arthritis, but not in the arthritis susceptible Lewis and Wistar strains. We suggest that resistance to autoimmune arthritis is associated with the presence of protective immunoglobulins and that their effect is carried out through the antigen recognition part of the molecule.     

Studies ofd-penicillamine on strain variability and lymph node cellularity in adjuvant arthritis

Experiments were performed in order to ascertain the action ofd-penicillamine (PA) on adjuvant arthritis (AA) in rats and to develop a quantitative evaluation method for PA-like drugs, using Lewis, SD, and Wistar rats. Rats were inoculated in the tail with 0.6 mg ofMycobacterium butyricum suspended in 0.1 ml of liquid paraffin. PA apparently induced enhancement of arthritis only in Lewis rats with a good reproducibility. The enhancing effect of PA was seen when it was administered during the period from day –7 to day –1, from day 0 to day 6, or from day 14 to day 20. In control group of Lewis and Wistar rats, adjuvant caused a rapid increase in the cell number of lymph nodes just after the inoculation, and also a marked increase in spleen cells coinciding with the development of arthritis. In PA-treated Lewis rats, the cell numbers of lymph nodes and spleen significantly surpassed those of control rats. However, PA induced no difference from control in Wistar rats, which were not sensitive to PA treatment during the course of arthritis. These results indicate that AA in Lewis rats is a good model for evaluating the activities of PA-like drugs and that PA may affect lymphocytes in lymph nodes and spleen and induce severer arthritis in Lewis rats.