Female MRL Research Articles

Involvement of oxidative stress in trichloroethene‐mediated autoimmunity

Reactive oxygen and nitrogen species (RONS) are implicated in the pathogenesis of several autoimmune diseases (ADs). Increased lipid peroxidation (LPO) and nitration are reported in systemic ADs. LPO-derived aldehydes (LPDAs) such as malondialdehyde (MDA) and 4-hydroxynonenal (HNE) are highly reactive and bind proteins covalently, but their potential to elicit an autoimmune response and contribution to disease pathogenesis remain unclear. Similarly, nitrated proteins could also contribute to disease pathogenesis. Therefore, the focus of this study was to establish a link between RONS and induction/exacerbation of autoimmune response. Autoimmune-prone female MRL +/+ mice (5-week old) were treated with trichloroethene (TCE), an environmental contaminant known to induce autoimmune response, for 48 weeks (0.5 mg/ml in 1% Alkamuls EL-620 via drinking water), and formation of autoantibodies to LPDA-protein adducts was followed in the sera of control and TCE-treated mice. Even though mice from both groups showed formation of anti-MDA-protein adduct antibodies, the response was significantly greater in TCE-treated mice. Similarly, TCE-treated mice also showed greater response for anti-HNE-protein adduct antibodies. TCE treatment in these mice resulted in higher serum iNOS and nitrotyrosine levels. Increased oxidative stress was also associated with remarkable increases in anti-nuclear-, anti-ssDNA- and anti-dsDNA- antibodies in the sera of TCE-treated mice. These findings clearly suggest that oxidative stress is closely associated with greater autoimmune response and could be an important mechanism in the pathogenesis of ADs. Supported by NIH ES013510.

Environmental Contaminant Trichloroethylene Promotes Autoimmune Disease and Inhibits T-cell Apoptosis in MRL+/+ Mice

The ability of environmental contaminant trichloroethylene to alter immune function and promote autoimmunity was tested in female MRL+/+ mice. MRL+/+ mice exposed to occupationally relevant doses of trichloroethylene in their drinking water for 32 weeks developed autoantibodies and pathological evidence of autoimmune hepatitis. The ability of trichloroethylene (TCE) to promote autoimmunity was associated with the expansion of activated (CD44hi CD62Llo) CD4+ T-lymphocytes that produced increased levels of the pro-inflammatory cytokine interferon (IFN)-γ. Activated T-lymphocytes can accumulate if activation-induced apoptosis is suppressed. Consequently, the effect of TCE on apoptosis in CD4+ T-lymphocytes was investigated. These experiments were conducted with TCE and one of the major oxidative metabolites of trichloroethylene, namely trichloroacetaldehyde hydrate (TCAH). CD4+ T-lymphocytes isolated from MRL+/+ mice exposed to TCE or TCAH in their drinking water for 4 weeks were resistant to activation-induced apoptosis in vitro. The TCE-or TCAH-induced decrease in activation-induced apoptosis was associated with decreased expression of FasL, one of the cell surface molecules that mediate apoptosis. These results suggest that exposure to the common water contaminant TCE or its metabolite TCAH inhibits activation-induced apoptosis in CD4+ T-lymphocytes, thereby promoting autoimmune disease by suppressing the process that would otherwise delete activated self-reactive T-lymphocytes.

A soy diet accelerates renal damage in autoimmune MRL/Mp- lpr/ lpr mice

Isoflavones, which are phytoestrogens present in large quantities in soy and soy-derived products, have estrogenic activity, inhibit protein tyrosine kinase, and exert other effects in the human body. Thus, the recent spread of soy consumption in Western populations emphasizes the need to more fully understand the potential effects in the body, especially in abnormal immune conditions. In the present study, the influence of a soy diet on lupus disease in MRL/Mp- lpr/ lpr (MRL/ lpr) mice was investigated. Weanling female MRL/ lpr mice (4 weeks) were fed a soy diet (20% soybean protein and 5% soybean oil). The soy diet exacerbated renal damage; findings in this mouse strain included accelerated proteinuria, elevated serum creatinine concentrations, and reduced creatinine clearance. No effects were detected, however, in C3H/HeN mice, which have the same H-2 k genetic background as MRL/ lpr mice do. A tendency toward an increase in thymus weight and proliferation of T cells in spleen and B cells in lymph nodes were found at the age of 16 weeks. These findings indicate that a soy diet, in comparison with a casein diet, significantly exacerbates the clinical course of this autoimmune disease. Further research on the mechanism of this effect of soy-rich diets is needed, and isoflavone supplementation for systemic lupus erythematosus patients should be carefully reevaluated.

Immunotoxic Response of Oleic Acid Anilide and its Hydrolysis Products in Female MRL +/+ Mice

An epidemic of a multi-systemic disease, known as the toxic oil syndrome (TOS), was caused by consumption of edible oil denatured with 2% aniline. Oleic acid anilide (OAA) has been suggested as one of the most likely etiologic agents responsible for TOS based upon its presence in high quantities in TOS-related oil samples. The aim of this study was to evaluate the immune response of OAA and contribution of its hydrolysis products (aniline and oleic acid) in the immunotoxic response. Female MRL+/+ mice were treated with equimolar doses of OAA, aniline or oleic acid (0.8 mmol/kg), i.p., twice a week for 6 weeks. The levels of immunoglobulins IgE, IgG and its isotypes (IgG1, IgG2a, IgG2 b, and IgG3), and the appearance of antinuclear antibodies (ANA) were determined in the serum. Exposure to OAA and oleic acid caused significant increases in IgG, IgG1, IgG2a, and IgG2b levels as compared to aniline and control groups, whereas IgG3 value increased only in OAA-treated mice. The IgE levels in OAA-, aniline-, and oleic acid-treated groups were higher than the controls. Among the various treatment groups, sera from 50% of the OAA-treated mice gave rise to intense homogenous fluorescence patterns on Hep-2 cells, suggesting the presence of significant levels of antinuclear antibodies (ANA). Furthermore, analysis of serum cytokines showed significant increases in G-CSF levels in OAA- and aniline-treated mice. Among the tissues examined, morphological changes were confined to the spleen, which showed increased lymphocyte population in OAA- and aniline-treated mice. These studies indicate that OAA and its hydrolysis products cause perturbations in the immune response, and could contribute to TOS-related immune derangements.

Selective Repopulation of Mice Liver after Fas-Resistant Hepatocyte Transplantation

Hepatocyte transplantation has been proposed as a potential therapeutic method to treat irreversible liver failure and inherited hepatic disorders, although transplanted cells do not easily reconstruct the liver tissue under intact conditions. This study was aimed at modulating the recipient liver conditions to promote repopulation of the liver after hepatocyte transplantation. Hepatocytes isolated from male MRL-lpr/lpr (lpr) mice with a mutation of Fas antigen were transplanted in a number of 1 x 10(6) cells in female MRL-+/+ (wild-type mice) by intrasplenic injection. An agonistic anti-Fas antibody (0.15 mg/kg) was administered intravenously 24 h after cell transplantation. We also administrated the antibody at 0.3 mg/kg 1 week after grafting and at 0.6 mg/kg 2 weeks after transplantation. The liver specimens were taken at different time intervals for histological examination. The reconstructed male lpr hepatocytes in the female wild-type mice were determined by a real-time quantitative PCR assay using the primers and probe for the sry gene. The pathologic findings of the recipient livers after treatment with anti-Fas antibody revealed a large number of apoptotic hepatocytes. The grafted lpr hepatocytes were observed to reconstruct as much as 6.9% of the recipient liver in the anti-Fas antibody-treated group 3 months after transplantation. In contrast, we observed the transplanted cells at lower than 0.1% in the nontreated livers. These findings demonstrated that repeated induction of apoptosis in recipient hepatocytes shifts the environment of the liver to a regenerative condition. This method may be useful to promote the reconstruction of transplanted hepatocytes in a recipient liver.

Anti-Malondialdehyde Antibodies in MRL+/+ Mice Treated with Trichloroethene and Dichloroacetyl Chloride: Possible Role of Lipid Peroxidation in Autoimmunity

Trichloroethene (TCE) and one of its metabolites dichloroacetyl chloride (DCAC) are known to induce/accelerate autoimmune (AI) response in MRL+/+ mice as evident from anti-nuclear, anti-ssDNA, anti-cardiolipin, and DCAC-specific antibodies in the serum (Khan et al., Toxicol. Appl. Pharmacol. 134, 155–160, 1995). In the present study, we measured anti-malondialdehyde antibodies (AMDA) in the serum of TCE- or DCAC-treated mice in order to understand the contribution of lipid peroxidation to this AI response. Female MRL+/+ mice (5 weeks old) received ip injections of 10 mmol/kg TCE or 0.2 mmol/kg of DCAC in corn oil (100 μl) every 4th day for 6 weeks, while controls received an equal volume of vehicle only, and AMDA was measured in the sera of these animals by an ELISA established in our laboratory. While TCE treatment caused only marginal induction of AMDA, DCAC treatment elicited a significant AMDA response. Furthermore, a time–response study of DCAC (0.2 mmol/kg, every 4th day, for 2, 4, 6, or 8 weeks) showed an induction of AMDA (3/4) after 4 weeks of treatment, which was even greater at both 6 and 8 weeks of DCAC treatment (5/5). These findings were further substantiated by the presence of AMDA in systemic lupus erythematosus-prone MRL-lpr/lpr mice as early as 6 weeks of age. Presence of AMDA, as observed in this study, not only indicates increased lipid peroxidation (oxidative stress), but also suggests a putative role of oxidative stress in inflammatory autoimmune diseases.

Effects of dietary ω3 and ω6 lipids and vitamin E on proliferative response, lymphoid cell subsets, production of cytokines by spleen cells, and splenic protein levels for cytokines and oncogenes in MRL/MpJ- lpr/lpr mice

ω3 Fatty acid rich fish oil (FO) and vitamin E may delay the progress of certain autoimmune diseases. The present study examined the mechanisms of action of ω3 lipids and vitamin E in autoimmune-prone MRL/ lpr mice suffering from extensive lymphoproliferation, lupus-like symptoms, and accelerated aging. To determine whether the effects of ω3 lipids in autoimmune disease is linked to vitamin E levels, weanling female MRL/ lpr and congenic control MRL/++ mice were fed diets containing 10% corn oil (CO) or 10% FO at two levels of vitamin E (75 IU or 500 IU/kg diet) for 4 months. The appearance of lymph nodes was delayed in the mice fed FO, and higher levels of FO offered further protection against the appearance of lymph nodes. Analysis of the spleen cells revealed that the cells positive for Thy.1 and Fas were significantly higher in the MRL/++ mice. The groups fed high levels of vitamin E generally exhibited higher levels of Fas. The proliferative response of splenocytes of MRL/++ mice to mitogens was significantly higher compared with MRL/ lpr mice. Interleukin (IL)-10 production by spleen cells was significantly higher in FO-fed MRL/ lpr mice than in CO-fed mice. In mice fed a high level of vitamin E, the production of IL-12 and tumor necrosis factor-α was significantly lower and IL-2 was significantly higher than in animals fed a low level of vitamin E. Proinflammatory cytokines were higher in the MRL/ lpr mice and both FO and vitamin E lowered the levels of proinflammatory cytokines and lipid mediators. Western blots revealed that c-myc and c-ras were significantly lower and IL-2 and transforming growth factor (TGF)-β1 levels were significantly higher in the spleens of MRL/++ mice. FO lowered c-myc and high levels of vitamin E in the diets normalized the levels of TGF-β1 in MRL/ lpr mice. The observations from this study suggest that both FO and vitamin E modulate the levels of specific cytokines, decrease the levels of proinflammatory cytokines, inflammatory lipid mediators, and c-myc, and increase TGF-β1 levels in spleens of MRL/ lpr mice and thus may delay the progress of autoimmune diseases.

P3C104 - Induction of anti-malondialdehyde antibodies in dichloroacetyl chloride-treated female MRL +/+ mice

A solid-phase extraction (SPE)–liquid chromatography (LC)–mass spectrometry (MS) method was developed to concentrate and detect nine cyanotoxins simultaneously, including six microcystins (MCs) congeners, nodularin (NOD), anatoxin-a (ATX) and cylindrospermopsin (CYN), in pure and natural waters. A dual cartridge SPE assembly was tested for the operating parameters of cyanotoxin extraction. A surrogate standard (SS), 1,9-diaminononane, was spiked in all the samples before the SPE extraction, and an internal standard (IS), 2,3,5-trimethylphenyl methyl carbamate, was spiked before LC/MS analysis. The method detection limit (MDL) was 2–100 ng/L for nine cyanotoxins in pure water and was increased by a factor of three to ten in a more complicated water matrix. The recoveries based on SS were between 83 and 104%, while those based on IS were 80–120%. The developed method was successfully employed in analyzing 33 water samples collected from eutrophic lakes, water treatment plants and distribution taps. MCs, NOD, and CYN were detected in the reservoir water, with concentrations as high as 36 μg/L. In addition, for the first time in Taiwan’s tap water, CYN was detected at concentrations as high as 8.6 μg/L. Quality control data for the field samples shows that the analytical scheme developed is appropriate for monitoring cyanotoxins.

Myeloperoxidase autoantibodies distinguish vasculitis mediated by anti-neutrophil cytoplasm antibodies from immune complex disease in MRL/Mp-lpr/lpr mice: a spontaneous model for human microscopic angiitis.

Anti-neutrophil cytoplasm antibodies (ANCA) with specificity for myeloperoxidase (MPO) occur in the sera of patients with microscopic angiitis, an autoimmune disease characterized by necrotizing vasculitis and crescentic glomerulonephritis. These autoantibodies have been shown to stimulate neutrophil degranulation and are believed to participate in pathogenesis. A neutrophilic vasculitis has been reported in MRL-lpr mice which has histological appearances similar to microscopic angiitis. In the present study we show that 22% of female MRL-lpr mice develop MPO autoantibodies. These animals develop a clinical syndrome of vasculitis and glomerulonephritis that is distinct from immune complex disease. Anti-MPO monoclonal antibodies derived from these mice are polyreactive and react with double-stranded DNA. They bind a conformational epitope on human MPO which is also expressed by activated human neutrophils. The results suggest that a subset of MRL-lpr mice develop ANCA-related vasculitis rather than systemic lupus erythematosus and may be used as a model for human microscopic angiitis.

Renal expression of fibrinolytic genes and tissue factor in a murine model of renal disease as a function of age.

Abnormal expression of fibrinolytic genes [e.g., tissue-type and urokinase-type plasminogen activators (t-PA and u-PA) and their specific inhibitor (PAI-1)] and of the procoagulant molecule tissue factor (TF), has been reported in various types of renal diseases. In this review, the expression pattern of these genes was demonstrated in two murine models of renal disease. One is acute renal failure due to microthrombosis under septic conditions, using endotoxin-treated mice, and the other one is lupus nephritis observed in female MRL lpr/lpr mice. Quantitative reverse transcription-polymerase chain reaction analysis and in situ hybridization were employed to investigate the expression of their mRNAs in tissues from endotoxin-treated mice or from MRL lpr/lpr mice. A dramatic increase in PAI-1 activity in plasma and in PAI-1 mRNA in the kidneys was observed in both models, and this increase appeared to correlate with fibrin deposition in the renal microvasculature and with the progression of lupus nephritis. In addition to these changes in PAI-1, decreases in u-PA mRNA and increases in TF mRNA were demonstrated in the kidneys from lupus-prone mice as a function of age. Similar changes were also observed in the kidneys from endotoxin-treated mice. The induction of PAI-1 and TF, and the decrease in u-PA expression in the kidneys of lupus-prone or of endotoxemic mice may promote the formation of renal microthrombi and thus contribute to the progression of renal damage in these models.

Time-Dependent Autoimmune Response of Dichloroacetyl Chloride in Female MRL +/+ MICE

Welders are exposed to dichloroacetyl chloride (DCAC) when trichloroethene (TCE) is used as a degreasing agent. Human exposure to TCE and tetrachloroethane can also lead to formation of DCAC in situ through metabolism. Due to its strong acylating property, it can bind with cellular macromolecules and act as hapten and consequently may elicit autoimmune (Al) response. Earlier, we reported that both TCE and DCAC induce/accelerate Al response in MRL +/+ mice, and DCAC even at 50 fold lower concentration induced greater Al responses. These studies, however, were conducted at a single time point (six weeks of treatment) and therefore necessitate a time-dependent characterization of this DCAC-induced Al response. Female MRL + /+ were given ip treatments of 0.2 mmol/kg DCAC in 100 μl of corn oil every 4th day, while controls received an equal volume of corn oil only. DCAC treatment resulted in spleen weight increases at all time points whereas serum IgG showed significant increases at 4, 6 and 8 weeks of treatment. Serum autoantibodies, i.e., anti-nuclear antibodies, anti-single stranded DNA antibodies and anti-cardiolipin antibodies showed positive responses only after 4 weeks of treatment. However, the optimal responses were observed at 6 weeks and subsequently the responses diminished (at 8 weeks). The DCAC-specific antibodies showed a pattern similar to autoantibodies, i.e., an optimal response at 6 weeks of treatment. Our results thus suggest that DCAC under the current experimental conditions induces an optimal Al response at 6 weeks of treatment and further emphasize the usefulness of MRL +/ + mice in studying chemical-induced autoimmunity.

Dietary vitamin A deficiency and the immune system in a murine model of systemic lupus erythematosus

The purpose of this study was to investigate the effects of dietary vitamin A deficiency on the onset and progression of systemic lupus erythematosus (SLE), a severe autoimmune disorder, using the murine SLE model, MRL MPJ - lpr lpr ( MRL l ) mice. Sixty weanling female 4-week old MRL lpr mice were randomly assigned to either the vitamin A-deficient (A −), A-sufficient (A +), and A-sufficient diet/feed restricted (DR) groups. The weight losses due to the onset of SLE for both the A+ and the DR groups were greater than that for the A- group (P<0.01 at 16 weeks of treatment or 24 weeks of age). Both thymus and spleen weights as the percentage of body weights for the A- group were lower than those for the A + and the DR groups within 12 weeks of diet treatment (or 20 weeks of age). The degree of the abnormality in splenocyte composition, viz. an increased ratio of Thy 1.2 (total T cells) and a relatively decreased ratio of SmIg positive splenocytes (total B cells), was more severe in both the A + and the DR groups than in the A − group. This change suggests that vitamin A deficiency may suppress the proliferation of abnormal T splenocytes in MRL l mice. The results of T and B splenocyte proliferation stimulated by mitogens, either concanavalin A (Con A) or lipopolysaccharide (LPS) in vitro, indicated that vitamin A deficiency exerted a suppressive effect on the activities of abnormal T and B splenocytes of MRL l mice. The deficiency of vitamin A in the diet also suppressed serum anti-DNA autoantibody production in MRL l mice. In summary, it caused a suppression in autoimmunity as expressed by a decreased hyperactivity in both cellular and humoral immune functions in MRL l mice. The overall results suggest that dietary vitamin A deficiency retarded the progression of SLE and resulted in a better survival of MRL l mice.

Trichloroethene-Induced Autoimmune Response in Female MRL +/+ Mice

Trichloroethene (TCE) has been implicated in the pathogenesis of autoimmune diseases such as systemic lupus erythematosus (SLE) and scleroderma in humans. However, experimental studies have not been conducted to establish the role of TCE in causing autoimmunity and/or SLE. To clarify the role of TCE in autoimmune responses, subchronic studies were carried out in female autoimmune prone mice (MRL +/+). Three groups of mice (5 weeks old) received intraperitoneal injections of 10 mmol/kg of TCE, 0.2 mmol/kg of dichloroacetyl chloride (DCAC) (one of the metabolites of TCE with strong acylating property), or an equal volume (100 μl) of corn oil alone (controls). Animals were dosed every 4th day for 6 weeks and euthanized 24 hr following the last dose. Sera and major tissues were collected and analyzed. Spleen weights in the TCE and DCAC groups increased 36% with a similar pattern of change in the spleen-to-body weight ratios. Serum IgG in the TCE and DCAC groups increased 45 and 322%, respectively. Using specific ELISA assays for mice, autoimmune antibodies were detected in the sera of TCE- and DCAC-treated mice in the following patterns: for anti-nuclear antibodies; controls, 0/4; TCE, 4/4; DCAC, 3/5; for anti-ssDNA antibodies; controls, 0/4; TCE, 2/4; DCAC, 5/5; for anti-cardiolipin antibodies; controls, 0/4; TCE, 0/4; DCAC, 3/5. An ELISA developed for the measurement of DCAC-specific antibodies using conjugated DCAC-albumin as an antigen showed the following pattern: for controls, 0/4; TCE, 0/4; DCAC, 5/5. These results suggest that TCE and its metabolite, DCAC, induce and/or accelerate autoimmune responses in female MRL +/+ mice. The greater responses induced by DCAC at a dose 50 times lower than TCE suggests that this metabolite may be important in the mechanisms leading to TCE-induced autoimmunity.

A Single Injection of Staphylococcus aureus Enterotoxin B Reduces Autoimmunity in MRL/ lpr Mice

MRL/Mp- lpr/lpr (MRL/ lpr) mice carry a mutation in the Fas gene whose product is involved in the regulation of lymphocyte apoptosis. This mutation is associated with the lpr phenomenon, i.e., a massive expansion of phenotypically abnormal CD4 -CD8 - cells ("double negative," DN) α/β T cells ( lpr cells) that becomes manifest at 3-4 months of age. As in normal mice, intravenous SEB injection into 2- or 6-month-old female MRL/ lpr mice causes a transient expansion of SEB-reactive V β8 + T cells, followed by a deletion of this subset. In contrast, in the same animals, the frequency of abnormal Vβ8 +CD4 -CD8 -cells is not modulated by SEB. Whereas DN T cells are completely resistant to SEB-mediated deletion in vivo, their precursors appear susceptible to SEB-induced deletion. Thus, a single injection of SEB prior to the surge of DN T cells in peripheral lymphoid organs, at 2 months of age, is sufficient to cause a stable long-term (6 months) deletion of DN cells. This is accompanied by a significant amelioration of autoimmune parameters (autoantibody titers, incidence of arthritis and nephritis), thus pointing to the feasibility of employing superantigens for simple manipulations of the immune repertoire that result in the long-term prophylaxis of autoimmune diseases.

Pulmonary perivascular and interstitial inflammation in [formula omitted] mice : III. Modulation by cyclophosphamide and sex hormones in 4- and 6- month-old animals

Estradiol (E) abolished clearing of pulmonary inflammation in 2-month-old male MRL MpJ - lpr lpr ( MRL l ) mice treated with cyclophosphamide (CY). To determine if this effect persisted in animals with advanced disease, we studied male and female MRL l mice, aged 4 and 6 months (4M, 6M, 4F, and 6F, respectively). Mice were treated, beginning at 1 month of age, with saline, CY (12 mg/kg/day), CY + castration, CY + castration + testosterone (T) in females, and CY + castration + E in males. CY had no effect on pulmonary inflammation in 4M, possibly because of the development of relatively mild lesions. However, CY was highly effective in 6M. CY + castration + T significantly reduced overall inflammation in 6F and showed a trend in 4F. CY alone had a variable effect on bronchoalveolar lavage fluid (BALF) cells and BALF IgG in both males and females. However, concurrent treatment with T was required for histologic changes of pulmonary inflammation to fully respond to a high dose of CY in female mice. E-treated males had reduced responsiveness to CY.

Diethyldithiocarbamate, a novel immunomodulator, prolongs survival in autoimmune [formula omitted] mice

MRL- lpr lpr mice die at an early age from a spontaneously developing systemic lupus erythematosus-like disease and are characterized by massive lymphadenopathy, hyperproliferation of Lyt-2 L3T4 (null) T cells, decreased responses to mitogens, thymic atrophy, and very high serum autoantibody levels. Diethyldithiocarbamate (DTC), an immunomodulator suggested to enhance T cells, was used to treat 12-week-old female MRL- lpr lpr mice (25 mg/kg/week). DTC treatment significantly prolonged survival (50% mortality, 43 weeks vs 20 weeks). Increased survival was associated with decreased lymphadenopathy, decreased proliferation of null cells, restoration of impaired mitogen responses, decreased thymic atrophy, and decreased serum levels of anti-DNA and anti-histone antibodies. Studies of cell surface antigen phenotype demonstrated increased expression of Lyt-2 and macrophage surface antigens. No effect on L3T4 single staining cells was observed. These results show that DTC significantly alters the disease course in these mice and suggest that DTC may be a useful treatment for autoimmune disease.

Androgen control of autoimmune expression in lacrimal glands of [formula omitted] mice

The purpose of the present study was to determine, by utilizing an animal model of Sjögren's syndrome, whether androgen therapy might ameliorate autoimmune sequelae in the lacrimal gland. Age-matched female MRL Mp - lpr lpr mice were administered subcutaneous implants of placebo- or testosterone-containing pellets after the onset of disease. Lacrimal glands and for comparison, submandibular glands were collected from sacrificed mice immediately prior to androgen administration and following 17 and 34 days of maintained hormone exposure. Tissues were processed for light microscopy and examined with a computer-assisted image analysis system. Results demonstrated that testosterone exposure dramatically reduced lymphocyte infiltration in lacrimal tissue: following 34 days of treatment, the percentage infiltrate had undergone a 12-fold decrease. This hormone action, which was time dependent, involved significant abrogations in both infiltrate size and number. Testosterone administration also induced a significant 2- to 3-fold rise in lacrimal gland weight and acinar area and a 2-fold reduction in acinar density/field, compared to values in placebo-treated controls. In addition, androgen administration significantly decreased the magnitude of lymphocyte infiltration in submandibular glands. Overall, our findings demonstrate that androgen therapy may reverse autoimmune sequelae in lacrimal, as well as submandibular, glands in a mouse model of Sjögren's syndrome.

Prevention of lupus diseases in [formula omitted], NZBxNZW, and BXSB mice treated with a cyclophosphazene derived drug

A polyclonal activation of lymphocytes (PA) has been suggested to play a pathogenic role in autoimmune and immune complex diseases, particularly in mouse lupus. “DIAM 4,” a cyclophosphazene derived drug, selected on the basis of its ability to modulate a PA has been used to treat female MRL I , female NZBxNZW, and male BXSB mice. In these three strains of mice, the treatment was found (I) to induce an inhibition of the PA, (2) to prevent the increase of anti-DNA antibody levels and the simultaneous decrease of C3 levels, (3) to prevent the appearance of proteinuria, the deposition of immune complexes in glomeruli, and the development of kidney lesions. Moreover in MRL I mice, lymphoproliferation was prevented. These results suggest that drugs able to modulate a PA might be efficient in the treatment of mouse lupus nephritis. Such a principle of immunomodulation might open the way to new possibilities of treatment of lupus and other immune complex diseases.

Increased Susceptibility to Leishmania tropica Infection in Autoimmune MRL/MpJ-lpr Mice

Homozygous possession of the single autosomal recessive gene, lpr (lymphoproliferation) is associated with increased susceptibility to acute infection with Trypanosoma cruzi in four congenic strains of mice (Boyer et al., 1983, Parasit. Immunol. 5: 135-142). Animals bearing the lpr gene, which controls certain autoimmune and lymphoproliferative manifestations (Murphy and Roths, 1978. In Genetic Control of Immune Disease, N. R. Rose, P. E. Bigazzi, and N. L. Warner (eds.). Elsevier North Holland, Amsterdam, pp. 207-220), show increased parasitemia or mortality when compared to their congenic partners that lack the gene. In the study described here we sought to determine if possession of the lpr gene might also influence susceptibility to another protozoan parasite, Leishmania tropica. Our data indicate that female MRL/MpJ-lpr mice injected with L. tropica promastigotes are susceptible to the infection, whereas their congenic partners, MRL/MpJ-+, are resistant to an identical dose of parasites. Because the two strains are of the same haplotype (H2k) and differ only in possession of the lpr gene, our results suggest that this single, non-H2-associated gene can influence susceptibility to infection with L. tropica. Leishmania tropica (WR 309) amastigotes were aspirated by needle from the lesions of infected BALB/cJ mice and allowed to transform into promastigotes. Eight-wk-old female MRL/ MpJ-lpr and MRL/MpJ-+ mice (Jackson Laboratory) were infected via subcutaneous injection of 5 x 107 organisms into the left rear footpad. The right rear footpad was injected at the same time with phosphate-buffered saline and footpad measurements (mm) made weekly with a Pocotest micrometer. The measurements on the MRL strains and additional C57BL/6J and BALB/cJ animals were expressed as the ratio between right and left footpad thicknesses. As seen in Figure 1 the two congenic MRL strains responded differently to infection with L. tropica. The MRL/MpJ-lpr mice were unable to control the parasites and showed a slow progressive expansion of the lesion. This result, albeit less pronounced than that found in L. tropica-sensitive BALB/cJ (H2d) mice is similar to that reported in DBA/1 animals (H2q) (Howard et al., 1980, Parasit. Immunol. 2: 303-314). Surviving MRL/MpJ-lpr animals also had metastatic lesions. MRL/MpJ-+ mice showed a pattern of lesion development similar to that of C57BL/6J (H2b) animals. Data on the genetic factors that influence susceptibility to L. tropica infection indicate substantial differences between mouse strains (Cox, 1981, Nature 291: 111-112). These differences appear to be largely H2-independent, although a certain retarding influence of H2k on the later stages of lesion growth has been observed in animals with the susceptible BALB/c (H2d) background (Howard et al., 1980, op. cit.). The hypersusceptibility of BALB/c mice is determined