Pulmonary clearance of Mycoplasma pulmonis in rats with respiratory viral infections or of susceptible genotype

We sought to determine whether or not increased severity of bronchopulmonary disease due to Mycoplasma pulmonis infection in rats with respiratory viral infections and in rats of susceptible genotype could result from altered pulmonary clearance. Pathogen-free rats were exposed to aerosols of radiolabeled M. pulmonis and the numbers of M. pulmonis colony-forming units, and amounts of radiolabel in the lungs were determined immediately after exposure or 4 hours later. Intrapulmonary killing of M. pulmonis during the 4-hour interval was determined from decreases in ratios of colony-forming units to radiolabel, and physical clearance was determined from decreases in radiolabel. Neither intrapulmonary killing nor physical clearance differed between control F344 rats and F344 rats inoculated with Sendai virus or sialodacryoadenitis virus, or between F344 and LEW rats. Rates of intrapulmonary killing and physical clearance were 64 +/- 3% and 44 +/- 2%, respectively (overall means +/- standard error).

Corticosterone-independent alteration of lymphocyte mitogenic function by amphetamine

Amphetamine, a neural stimulatory agent with acute effects mimicking those of stress, is shown here to elevate plasma corticosterone levels and suppress spleen and peripheral blood lymphocyte (PBL) mitogenic responses to concanavalin A (Con A) and phytohemagglutinin (PHA) when administered to rats. Pretreatment of the rats with propranolol, a nonselective beta-adrenergic receptor antagonist, totally prevented the amphetamine-induced suppression of lymphocyte mitogenic reactivity to Con A and PHA in the spleen and to PHA in the peripheral blood; however, the PBL mitogenic response to Con A was only partially restored. Although the amphetamine-induced alterations in immune function were prevented by propranolol pretreatment, the elevated plasma corticosterone response was not. This suggests that corticosterone is not modulating the mitogenic activity of splenic lymphocytes or PHA-reactive PBLs. On the other hand, Con A-reactive PBLs may be affected by corticosterone and/or other mechanisms, which may include the catecholamines.

Immune system of the spontaneously hypertensive rat. I. Sympathetic innervation

Extensive bidirectional interactions are believed to exist between the sympathetic nervous system and the immune system. The spontaneously hypertensive rat (SHR) is known to possess both increased sympathetic nervous system activity with increased tissue catecholamine levels in several peripheral organs and a moderate T lymphocyte immune deficiency. We examined the development of innervation in both primary (thymus) and secondary (spleen) organs of the immune system of the SHR compared to immunocompetent Wistar-Kyoto (WKY), Fisher 344 (F-344), and Long Evan (LE) rats from birth through 24 weeks. Using glyoxylic acid-induced histofluorescence to visualize monoaminergic nerve fibers, coded specimens were examined and morphologically evaluated for the extent and distribution of innervation. The innervation of the SHR thymus was significantly increased at 2 and 12 weeks of age over the other strains. Unlike the control strains, splenic innervation in SHR was delayed until 2 weeks of age when it suddenly became exuberant. At 12 weeks, the innervation of the SHR spleen was increased over all control strains. By 24 weeks the innervation had regressed to a level comparable to the levels of the other rat strains in these tissues. During the suckling period, the size (weight) of the WKY spleen was larger and the level of innervation was decreased compared to the other strains. These strain-related differences in the development of sympathetic innervation of thymus and spleen likely reflect the complex, bidirectional interplay between the nervous and the immune systems.(ABSTRACT TRUNCATED AT 250 WORDS)

Stress-induced alterations in interferon production and class II histocompatibility antigen expression

Mild electric foot-shock has been shown to be a stressor that can alter immune responses. Male Lewis rats were exposed to one session of 16 5.0-s 1.6-mA foot-shocks. Production of interferon-gamma by splenocytes in response to concanavalin-A was decreased in spleens from the shocked rats compared to control spleens. Spleen cells from rats treated with nadolol, a peripherally acting beta-adrenergic receptor antagonist, and then shocked, showed dose-dependent attenuation of the suppression of interferon-gamma production. This suggests that catecholamines mediate shock-induced suppression of interferon-gamma production. The percentage of splenic mononuclear cells expressing class II histocompatibility (Ia) antigens on their surfaces from spleens of shocked rats was determined by flow cytometry. Significantly decreased class II positive mononuclear cells were present in the spleens of shocked rats in comparison to the spleens of control rats. This may reflect an alteration of cell trafficking or decreased production of class II antigens.

Shared T-cell receptor gene usage in experimental allergic neuritis and encephalomyelitis

Experimental allergic neuritis, an autoimmune disease of the peripheral nervous system, is a model for human Guillain-Barré syndrome. Experimental allergic neuritis is mediated by CD4+ T cells reactive with myelin P2 protein. We demonstrate that these T cells use the same members of T-cell receptor V gene families for both their alpha (V alpha 2) and beta (V beta 8) chains as T cells that cause experimental allergic encephalomyelitis, an autoimmune disease of the central nervous system. Furthermore, these T cells appear to be idiotypically related. Therefore, completely different T-cell lines with different antigen specificities, producing entirely different diseases, share common T-cell receptors.

Modulation of immune status by a conditioned aversive stimulus: evidence for the involvement of endogenous opioids

Recent research has shown that presentations of an unconditioned aversive stimulus, such as electric shock, can induce alterations of immune function in rats. Furthermore, it has been demonstrated that an innocuous stimulus paired with an unconditioned aversive stimulus can acquire immunomodulatory properties. Research has suggested that endogenous opioid activity is responsible for the alterations of immune function by unconditioned aversive stimulation. The present study evaluated the effect of administration of opiate receptor antagonists, naltrexone and N-methylnaltrexone, on the immunomodulatory effect of a conditioned stimulus (CS) that had been paired with electric footshock. Naltrexone dose-dependently attenuated the CS-induced suppression of the in vitro proliferative response of splenic lymphocytes to concanavalin A, lipopolysaccharide, and a combination of ionomycin and phorbol myristate acetate. Naltrexone also attenuated the CS-induced reduction in natural-killer cell activity. In contrast, the quaternary form of naltrexone, N-methylnaltrexone, did not significantly attenuate the CS-induced immunomodulatory effects. Collectively, these findings indicate that endogenous opioid activity is involved in CS-induced alterations of immune function. Moreover, the lack of effectiveness of N-methylnaltrexone in attenuating the CS-induced immunomodulatory effect suggests that the opioid receptors involved in the effect are located in the central nervous system.

Suppression of the development of adjuvant arthritis by a conditioned aversive stimulus

The present study evaluated the effect of a conditioned aversive stimulus (CS) on the development of adjuvant-induced arthritis in Lewis rats. Experiment 1 showed that presentation of a CS, on days 12, 14, and 16 following injection with adjuvant containing mycobacterium tuberculosis, resulted in a pronounced suppression of the development of arthritis as measured by a clinical disease severity rating scale and spleen weight. In contrast, presentation of the CS on days 0, 2, and 4 following injection did not have any effect on the development of arthritis. Experiment 2 showed that the suppression of adjuvant arthritis by exposure to the CS was blocked by administration of propranolol, a nonselective beta-adrenergic receptor antagonist. These results demonstrate that a CS can alter the development of adjuvant-induced arthritis, but the effect is dependent upon the timing of the antigen exposure and the presentation of the CS. Moreover, the present findings suggest that blocking beta-adrenergic receptors during presentations of the CS prevents the suppressive effect of the CS.

Facial nerve transection causes expansion of myelin autoreactive T cells in regional lymph nodes and T cell homing to the facial nucleus

Nervous tissue expression of immunological signal and recognition molecules, as well as lymphoid tissue immune responses after facial nerve trauma was studied in male rats of the Lewis and Brown Norway (BN) strains. In both rat strains nerve transection caused within four days the appearance of IFN-gamma-like immunoreactivity in the cytoplasm of axotomized motor neurons and an induction of MHC class I and II, and CD4 molecules on surrounding glial cells to a similar extent. T lymphocytes also infiltrated the facial nuclei ipsilateral to the axotomy in all animals. The number of autoreactive T cells in superficial cervical lymph nodes, which in response to whole myelin or peptides of myelin basic protein (MBP) secreted IFN-gamma increased markedly after axotomy. This response was more conspicuous in Lewis rats, which are susceptible to experimental allergic encephalomyelitis (EAE), than in BN rats, which are EAE resistant. A proportion of the axotomized Lewis rats also developed widespread perivascular infiltration of mononuclear cells in the CNS, reminiscent of EAE. Hypothetically, a strong expansion of myelin autoreactive IFN-gamma producing T cells secondary to nerve trauma may have immunopathological consequences in genetically predisposed individuals. It is also possible that myelin reactive T cells, whether recruited to the lesioned nerve, could have impact on macrophage function during Wallerian degeneration in the distal stump.

Suppression of experimental autoimmune uveoretinitis by intraorchidic administration of S-antigen

Experimental autoimmune uveoretinitis (EAU) induced by immunization of albino Lewis rats with a retinal soluble antigen (S-antigen) has been studied extensively by many workers. An intraorchidic injection of S-antigen 4 days prior to immunization of the animal with the antigen emulsified in adjuvant was found to prevent the onset of the disease. Orchiectomy in 24 hr after the intraorchidic injection did not abolish the effect of treatment. The systemic suppression induced by the orchidic treatment persisted at least for 3 weeks after treatment. In rats that received orchidic treatment, delayed-type hypersensitivity was markedly inhibited but anti-S-antigen antibody levels in the serum were as high as those in immunized rats without orchidic pretreatment. These results indicate that antigen challenge to the testis is a novel method to systemic activation of the immunosuppressive mechanism.

Thymus-mediated immune tolerance to renal allograft is donor but not tissue specific

Studies were conducted in Lewis (RT1l) rats to determine whether the process of unresponsiveness to kidney graft induced by the intrathymic glomerular transplantation were donor-strain specific as suggested by previous studies (Remuzzi et al., Lancet 1991;337:750-752). When glomeruli from Sprague-Dawley rats were injected in the thymus of Lewis rats, the subsequent kidney graft from a "third party" Brown-Norway (RT1n) rejected within 9 to 14 days. Moreover, an alternative site for glomerular antigen inoculation, such as i.p. administration, failed to induce a state of unresponsiveness to renal allograft. Whether tolerance was tissue specific was investigated by intrathymic injection of a preparation of donor blood cells that only included white cells. Such a maneuver, followed 10 days later by a kidney transplant, allowed indefinite renal graft survival in all animals, whereas all rats injected intrathymically with blood cell medium alone rejected the kidney graft in 8 to 11 days. Shortening the time interval between intrathymic injection of blood cells and kidney transplantation still allowed the graft to survive indefinitely. Finally, Lewis (RT1l) rats with chronic renal failure injected intrathymically with blood cells from Brown-Norway (RT1n) rats tolerated indefinitely a subsequent kidney graft from the same donor. These findings indicate that (1) the induction of immune tolerance to renal allograft induced by intrathymic injection of antigens is donor but not tissue specific; (2) the time interval between intrathymic injection of donor cells and the subsequent kidney transplantation can be reduced to 24 h; and (3) uremia does not preclude the possibility of renal allograft tolerance after the thymus procedure.

Behavioral conditioning prolongs heart allograft survival in rats

Conditioned immunosuppression using a taste aversion paradigm has been demonstrated in a number of laboratory models but few reports have demonstrated changes in immunity sufficient to be of clinical relevance. The experiments reported here demonstrate that the survival of heart allografts in rats can be prolonged by behaviorally conditioned immunosuppression using cyclosporin A (CsA) as an unconditioned stimulus in taste aversion conditioning. Conditioned animals received saccharin as the conditioned stimulus paired with an injection of CsA at 10 and 6 days prior to transplantation. They were reexposed to saccharin alone 1 day prior to and 3 days after transplantation. On these occasions the conditioned group displayed taste aversion behavior when offered saccharin and a significant prolongation of heart graft survival was observed compared to the conditioned and nonconditioned control groups. These experiments suggest that behaviorally conditioned immunosuppression may have important clinical implications as an adjunct to drug treatments in transplantation medicine.

Effects of gangliosides on the expression of autoimmune demyelination in the peripheral nervous system

To test whether gangliosides (GA) might exert neuritogenic effects in vivo, experimental allergic neuritis (EAN) was studied clinically, neuropathologically, and immunologically in Lewis rats immunized with bovine peripheral nerve, P2 myelin protein, P2 myelin protein plus two different doses of GA, P2 with galactocerebroside (GC), and GA alone, each emulsified in adjuvant. All except the GA-treated group developed signs of EAN between days 11 and 14 after the injection. Rats immunized with P2 alone were the most severely affected. Rats given P2 plus GA and those given P2 plus GC displayed a significantly lower clinical score. Histological analysis revealed a comparable degree of inflammation of the peripheral nervous system and demyelination in the spinal nerve roots of bovine peripheral nerve- and P2-immunized rats. The P2 plus GA and P2 plus GC groups revealed similar degrees of pathology in the spinal nerve roots but the latter group stood apart from the rest in that it showed widespread peripheral nervous system changes extending distally into the sciatic nerve. Serological analysis demonstrated that P2 and GC, but not GA, elicited antibody (IgG) responses, but there was no correlation between antibody titer and clinical or histological involvement. The present data fail to support an enhancing role for gangliosides in the expression of EAN and, by extrapolation, in the Guillain-Barré syndrome, for which EAN serves as the laboratory model, and in which suggestions have been made that antibodies to GA may have pathogenetic significance.

Monoclonal antibodies against myelin proteolipid protein: identification and characterization of two major determinants

This report describes the preparation and characterization of a panel of monoclonal antibodies (mAbs) against the myelin proteolipid protein (PLP). A Lewis rat was immunized with bovine proteolipid apoprotein and 27 mAbs were selected based on their reactivity against bovine PLP on enzyme-linked immunosorbent assays. Eleven mAbs recognized the PLP carboxyl-terminal sequence when tested against a panel of synthetic peptides in a solid-phase assay. A carboxyl-terminal pentapeptide (residues 272-276) was sufficient for antibody binding and the terminal phenylalanine residue was found particularly important. Deletion, modification, or replacement of this residue markedly reduced or obliterated antigen-antibody interaction. Nine mAbs reacted with a second antigenic determinant, residues 209-217, but these could be identified only by competitive immunoassays. This peptide was a more effective inhibitor than the longer peptides 202-217 and 205-221, suggesting that flanking residues may interfere with peptide-antibody interaction. Seven antibodies did not react with any of the synthetic peptides tested and their determinants remain unidentified. Immunoblot analysis showed that the mAbs reacted with both the PLP and the DM-20 isoforms. Twenty-three of the mAbs were of the immunoglobulin G2a or b isotype; the remaining antibodies were immunoglobulin M and all of these were specific for residues 209-217. Cultured murine oligodendrocytes were stained by most of the mAbs tested, but the most intense reactivity was observed with the carboxyl-terminus-specific mAbs. The immunocytochemical analyses demonstrate that the mAbs react with the native PLP in situ and show their potential usefulness for studies of the cell biology of myelin and oligodendrocytes.

Analysis of the expression and immunostimulatory capacity of class I major histocompatibility antigens on rat trophoblast cell lines

In rat strains expressing the a and other major histocompatibility complex (MHC) haplotypes, subpopulations of placental trophoblast cells synthesize the nonclassical class I Pa antigen in preference to the classical RT1.Aa antigen. In this study, a rat trophoblast cell line, R8RP.3, which was derived from midgestation placentas of PVG.R8 (RT1.Aa) rats, was shown to express class I antigens similarly to those of trophoblast cells in situ. Both unstimulated and IFN-gamma-exposed metabolically labeled R8RP.3 cells synthesized more Pa than RT1.Aa antigen. The reverse was true for labeled spleen cells from PVG.R8 rats. The R8RP.3 cells failed to stimulate allogeneic lymphocyte proliferation even when high levels of both classical and nonclassical class I MHC antigens were expressed on their membranes after incubation with IFN-gamma. These experiments thus supply the first evidence that the inductive phase of the immune response is not promoted by trophoblast cell class I MHC antigens, which could explain the failure of mothers to mount immune responses to class I MHC positive trophoblast cells.

Factors that influence fertility after vasovasostomy in rats

OBJECTIVE

To determine if fertility after vasovasostomy of immunologically responsive Lewis rats differs from that of the less responsive Sprague-Dawley strain and to relate fertility to antisperm antibodies, fluid flow in the vas deferens, and testicular structure.

DESIGN

Male rats received: (1) bilateral vasectomies; (2) vasectomies followed 3 months later by vasovasostomy; or (3) sham operations.

SETTING

Research laboratory.

MAIN OUTCOME MEASURES

Fertility was assessed by caging males with three females for 2 weeks and subsequently counting implantation sites. Antisperm antibodies were measured with an enzyme-linked immunosorbent assay, fluid flow through vas deferens segments was tested in vitro, and testicular structure was studied microscopically.

RESULTS

Nearly all vasovasostomized Lewis rats were infertile (33 of 34), whereas 62% (18 of 29) Sprague-Dawley rats were fertile after vasovasostomy (P less than 0.001). In fertile Sprague-Dawley males, significant correlations existed between: (1) implantation sites or females impregnated; and (2) antisperm antibodies early after vasectomy, vas flow, and testicular morphology.

CONCLUSIONS

Genetic differences affect fertility after vasovasostomy. Fertility after vasovasostomy is also influenced in a multifactorial manner by the immune response, mechanical elements, and structural changes in the reproductive tract.

Clonal diversity of basic protein specific T cells in Lewis rats recovered from experimental autoimmune encephalomyelitis

T cell lines selected from Lewis rats recovered from experimental autoimmune encephalomyelitis (EAE) respond not only to the immunodominant 72-89 epitope of basic protein (BP), but also to secondary epitopes including the I-A restricted 43-67 region of guinea pig (Gp) BP and the I-E restricted 87-99 sequence of rat (Rt) BP. The current study demonstrates at the clonal level the diversity of T cell responses to Gp- and Rt-BP in EAE-recovered rats. As predicted from the response pattern of BP-selected T cell lines, T cell clones from the lines responded to both the dominant and secondary epitopes of BP. In addition, a new majority clonal type was identified that responded to whole BP but not to epitopes represented on enzymatic cleavage fragments or synthetic peptides spanning the BP molecule. Clones representative of each of the three types of Gp-BP responses were characterized for phenotype, major histocompatibility complex restriction, and biologic activity in vivo. All of the clones were strongly CD4+ and co-expressed CD8 at modest levels as measured by both immunofluorescence and Northern blots. All three T cell specificities were I-A restricted. However, only the 72-89 responsive clone could transfer clinical EAE, due most likely to its unique ability to respond to Rt-BP. In contrast, the Gp-BP 43-67 reactive T cell clone transferred protection against EAE, whereas the whole Gp-BP reactive clone transferred delayed-type hypersensitivity response but was neither encephalitogenic nor protective. Thus, the recovery process from EAE is distinguished by an increased diversity of protective clones as well as innocuous clones that may be spawned as encephalitogenic T cells are regulated.

Factor XIII of blood coagulation inhibits the oxidative phagocyte metabolism and suppresses the immune response in vivo

Factor XIII of blood coagulation (F XIII) belongs to the family of transglutaminases and is a major cell product of certain subsets of macrophages. The gene for F XIIIA is coupled to the immune response genes of the HLA-region on chromosome 6. F XIII dose- dependently inhibits the in vitro chemiluminescence response of human phagocytes. About 0.1 units of F XIII/ml (final) decreased the chemiluminescence response to about 50%. In addition, about 0.6 units of F XIII/ml inhibits 50% of the release of the lysosomal hydrolase N-acetyl-beta glucosaminidase in both immune complex stimulated and unstimulated monocytes. Intraperitoneal application of F XIII reduced the activity of phagocytes in a F XIII dose dependent manner. 0.25 units of F XIII reduced the chemiluminescence reaction of murine peritoneal M phi to about 50% of the activity of PBS treated animals after 2 or 24 hours of in vivo incubation. In the Fisher/Lewis rats skin transplantation model, injections of 5 units of F XIII/animal on days 1-7 or on days 10-17 increased the survival times of the transplants from the control value of 17.0 +/- 1.4 to 26.0 +/- 2.0 and 23.0 +/- 2.4 days, respectively. F XIII may represent a novel and physiological immune suppressive agent for a broad range of human diseases of autoimmune character.

[Role of food antigens and alcohol in idiopathic nephritis with IgA deposits]

It is generally thought that antigens inducing the formation of IgA immune complexes in primary IgA nephropathy and responsible for mesangial immune deposits are of infectious and alimentary origin. To investigate the possible role of alimentary antigens in eliciting the IgA mucosal immune response we studied the reactivity and the formation of mesangial IgA deposits in rodents following different experimental conditions: a) on gluten-free diet and oral immunization with gliadin; b) on gluten and soya free diet and oral immunization with soya; c) on chronic alcoholic intoxication. We found that oral immunization with gliadin induced the formation of mesangial deposits of IgA similar to those observed in human primary IgA nephropathy. On the contrary, oral immunization with soya failed to induce the formation of similar immune deposits even though the lectin components in soya and in gliadin are similar. Chronic ethanol intoxication induced an increase in serum IgA against alimentary antigens suggesting an increase in intestinal permeability due to alcohol. Mean times we observed significant IgA mesangial deposits. Our experimental data suggest that alimentary antigens can play a significant role in inducing primary IgA nephropathy.

Separation of pluripotent stem cells and early B lymphocyte precursors with antibody Fall-3

A major goal in the study of hematopoiesis is to obtain populations of primitive stem cells, free of restricted and mature cells. We previously showed that a small population of normal bone marrow, the Thy-1loLin- cells, was highly enriched for pluripotent stem cells that repopulate lethally irradiated mice. These cells also differentiated along the B lymphocyte lineage in response to the stromal elements in Whitlock-Witte cultures. These two hematopoietic activities were entirely contained in and were enriched to similar extents in the Thy-1loLin- population. Here we show for the first time that these two activities can be resolved functionally and phenotypically. The cells that respond to the stroma in lymphoid culture are more sensitive to the cytotoxic drug 5-Fluorouracil than are stem cells. Furthermore, we have derived a new monoclonal antibody, Fall-3, that detects primitive stem cells but does not label the B cell precursor. This indicates that the small Thy-1loLin- population is heterogeneous, containing precursors restricted to the B cell lineage as well as pluripotent stem cells. Antibody Fall-3 defines a novel stem cell antigen, expressed on all primitive stem cells and thus, will be useful in the further characterization and isolation of both stem cells and B cell precursors.

Complement-dependent antibody-mediated cytotoxicity (C'AMC) to pancreatic islet cells in the spontaneously diabetic BB/OK rat: interference from cell-bound and soluble inhibitors

Sera from 30 newly diagnosed diabetic BB/OK rats were analyzed cross-sectionally for complement-dependent antibody-mediated cytotoxicity (C'AMC) to pancreatic islet cells using different 51Cr release test systems. The sera contained enough active complement to lyse either sheep erythrocytes or 51Cr-labelled rat islet cells that had been sensitized with specific rabbit antibodies, but, in the presence of BB/OK rat islet cell antibody they released significant amounts of islet cell-bound 51Cr only after addition of rabbit complement. In a one-step assay, 19 out of the 30 sera produced lysis significantly above that by sera from the non-diabetes-prone WOK strain. This was increased 2.5-fold (p less than 0.01) by briefly washing the serum-treated cells before adding complement (two-step assay), indicating that C'AMC inhibitory activity was present in the diabetic sera. Some inhibitory activity could still be detected in heated sera but only when they were added to the cells immediately before the rabbit complement. Islet cell lysis was still substantial after preferential inactivation of factor B of the alternative complement activation pathway (by heating at 50 degrees C), and thus mainly depended on the classical pathway. From these findings it is concluded that (a) islet cell surface antibodies in diabetic rats activate heterologous complement via the classical pathway, (b) anti-islet C'AMC is sensitive both to species-restricted interference in interactions between homologous antibody and homologous complement in the target cell membrane, and to a distinct serum inhibitor that impairs the ability of membrane-fixed BB/OK rat antibody to interact with rabbit complement.

Suppression of experimental autoimmune encephalomyelitis by oral administration of myelin antigens: IV. Suppression of chronic relapsing disease in the Lewis rat and strain 13 guinea pig

Oral administration of proteins is a long-recognized method of inducing antigen-specific peripheral immune tolerance. We previously showed that oral administration of myelin basic protein suppresses monophasic experimental autoimmune encephalomyelitis in the Lewis rat when it is given in association with immunization and prior to disease onset. As a potential therapy for human autoimmune disease, it is crucial to determine whether oral tolerance can ameliorate an ongoing immune response. We therefore asked whether oral administration of myelin antigens, after sensitization and disease expression has occurred, could affect immunological, clinical, or pathological features of experimental autoimmune encephalomyelitis. Chronic relapsing experimental autoimmune encephalomyelitis was induced in the Lewis rat and strain 13 guinea pig by immunization with whole guinea pig cord homogenate, complete Freund's adjuvant, and Mycobacterium tuberculosis. Following recovery from the first attack, animals were orally given bovine myelin, guinea pig myelin, or guinea pig myelin basic protein three times per week for up to 3 months. Animals receiving myelin products orally had decreased severity and frequency of clinical relapses, decreased delayed-type hypersensitivity responses to myelin antigens, diminished inflammation in the central nervous system (CNS), and decreased areas of CNS demyelination. In the rat, guinea pig myelin basic protein was as effective as guinea pig myelin in ameliorating the disease and also resulted in decreased serum anti-myelin basic protein antibody levels. No exacerbation of disease or worsening of pathological findings occurred in the animals given myelin products. These results demonstrate that oral administration of myelin antigens can suppress chronic relapsing experimental autoimmune encephalomyelitis and have direct relevance to therapy of human demyelinating disorders such as multiple sclerosis.

Increased serum IgG2b and IgM & IgG1 Fc receptors expressed on tissue mast cells in experimental GVHR and HVGR rat models

Chronic graft-versus-host reaction (GVHR) due to male specific (H-Y) antigen was induced by the injection of syngeneic (DA x Lewis) F1 female cells into (DA x Lewis)F1 male rats. Chronic host-versus-graft reaction (HVGR) based on major histocompatibility complex (MHC) (RT1a) occurred when host Lewis (RT1(1)) rats were transplanted (DA x Lewis)F1 donor cells (RT1a & RT1I). Chronic GVHR and HVGR were activated at fixed periods. The first attacks of the GVHR and HVGR were recognized 50-80 days after cell transplantation, but the most intensive attacks of both responses were observed 120-175 days after cell transplantation. During the most intensive attacks, two rats died from either GVHR or HVGR. Rat immunoglobulin assays measured by radial immunodiffusion (RID) showed that serum IgG2b rose to 10.600-11.500 mg/ml in the rats that had the advanced GVHR or HVGR. The tissue mast cells derived from the loose lymphoid tissues of the medullary and subcapsular sinuses have proliferated in the mesenteric lymph nodes of the rats. IgM and IgG1 binding Fc receptors expressed on the mast cells were demonstrated indirectly using alkaline phosphatase conjugated ant-rat IgM and anti-rat IgG1.

T cell receptor beta-chain usage in experimental autoimmune uveoretinitis

Genomic rearrangements to the T-cell receptor (TCR) V beta 8 gene locus were examined in T cells derived from the lymph nodes of Lewis rats immunized with either S-Antigen or peptides derived from interphotoreceptor retinoid binding protein (IRBP). The cells used in these studies are from T-cell lines that have been selected by several cycles of antigen/IL-2 stimulations, or clones isolated from these lines. No apparent rearrangement of the V beta 8 gene was observed by Southern analysis, suggesting that if indeed there are T cells using V beta 8 gene elements they represent small proportions of the cells in these T-cell lines that induce EAU (uveitogenic T cells) and that the lines may consist of large numbers of clones. On the other hand, we have demonstrated V beta 8 gene expression in uveitogenic T-cell populations by Northern analysis and by polymerase chain reaction (PCR). Although V beta 8 gene transcripts were detectable in pathogenic, but not in non-pathogenic, T-cell lines using a V beta 8 cDNA probe, RNA from pathogenic T cell lines did not hybridize to another probe specific for rat V beta 8.2. Taken together, these results suggest that, unlike the T-cell lines that mediate experimental allergic encephalomyelitis (EAE), some T-cell lines that induce EAU do not predominantly express V beta 8.2 gene but other member(s) of the V beta 8 family.