Interferon-induced expression of class II major histocompatibility antigens in the major histocompatibility complex (MHC) class II deficiency syndrome

Class II antigens encoded by genes of the major histocompatibility complex (MHC) are expressed by a variety of cell types and have a vital role in the cellular interactions required for an effective immune response. We have analyzed the regulation of HLA-DR, DP, and DQ class II antigen expression on cells of different lineage from an immunodeficient patient with the MHC class II deficiency syndrome. T and B lymphocytes, monocytes, and fibroblasts, which initially expressed no class II antigens, were treated with inductive stimuli that normally lead to enhanced expression of class II antigens. Monocytes, but not fibroblasts, cultured for 48–96 hr in the presence of recombinant gamma interferon expressed all three types of class II antigens. In contrast, T lymphocytes did not express class II antigens following their exposure to a variety of stimuli, including activation with phytohemagglutinin and culture in the presence of interleukin-2, transformation by the retrovirus HTLV-1 or HTLV-2, or exposure to the demethylating agent 5-azacytidine. Similarly, class II antigens were not induced on B cells by cross-linkage of surface immunoglobulin molecules with anti-mu, exposure to Epstein-Barr virus, or treatment with soluble factors secreted by activated T cells. These results demonstrate that the regulation of class II MHC antigen expression by monocytes and lymphocytes is dissimilar and suggest that different regulatory genes are involved in the control of class II antigen expression by cells of different lineage.     

Enhanced MHC class II expression in renal proximal tubules precedes loss of renal function in MRL/lpr mice with lupus nephritis

Enhanced MHC class II (Ia) antigen expression is a common feature of autoimmunity. The authors investigated the occurrence of renal Ia expression in MRL/MpJ-lpr/lpr (MRL/lpr) mice with lupus nephritis. By immunoperoxidase staining, normal C3H/FeJ and the congenic strain MRL/MpJ-+/+ express Ia in mononuclear cells in the interstitium only, whereas MRL/lpr with nephritis have abundant Ia expression in proximal tubules (PT), mainly towards the basolateral membrane, and in the characteristic perivascular infiltrates. To a lesser extent, enhanced Ia expression is also observed in the interstitium and in the glomerular mesangium. By Northern blot analysis, the increase in Ia surface determinants correlates with an increased steady-state level of class II mRNA for both I-A and I-E. Ia expression on PT starts focally at around 2-months of age, often in proximity to vascular infiltrates, and precedes overt glomerulo-nephritis and proteinuria. Enhanced class II expression is not restricted to the kidney. MRL/lpr have also increased interstitial class II antigen expression in liver, lung, and spleen compared with normal C3H/FeJ mice. Thus, MRL/lpr mice have enhanced systemic Ia expression, but Ia antigen expression is particularly prominent in PT and may play a key role in the initiation and progression of lupus nephritis.     

Enhanced major histocompatibility complex (MHC) class II antigen expression in lupus nephritis

Thirty-eight cases of lupus nephritis, all satisfying the American Rheumatism Association criteria for diagnosis of systemic lupus erythematosus (SLE), with renal involvement and biopsy were immunohistochemically studied for the expression of HLA-DR (DAKO: HLA-DR/alpha, TAL.1B5), one of the three known families belonging to the class II major histocompatibility complex (MHC), using a standard streptavidin-biotin-peroxidase method. 20 nephrectomies performed for renal trauma and tumours constituted the normal controls. Of the lupus nephritis cases, 34 were females and 4 males. Ethnically, 20 were Chinese, 13 Malay, 4 Indian and 1 of indigenous origin. Their ages ranged from 16 to 59 years (mean of 31 years). Histologically, 23 expressed World Health Organisation (WHO) class IV (diffuse proliferative), 10 WHO class V (diffuse membranous), 4 WHO class II (pure mesangiopathy) and 1 WHO class III (segmental and focal proliferative) nephritis. Activity scores ranged between 5 to 19 (mean = 8.6) and chronicity scored between 2 to 7 (mean = 3.2) on a standard scoring system. Similar to other studies, HLA-DR was expressed in the glomerular capillaries and peritubular capillaries of all and mesangium, tubules (proximal, distal and collecting), veins and arterioles of some normal controls. Interestingly, HLA-DR expression was noted in the arteries of 25% of the normal controls, a finding hitherto not reported. The frequency of lupus nephritis cases expressing HLA-DR in the various anatomical components did not differ significantly from the normal controls except that HLA-DR expression in arteries and arterioles was seen at a significantly increased frequency (p < 0.01) in lupus nephritis. This increased expression did not correlate with the WHO class, activity or chronicity scores. It therefore appears that MHC class II shows increased expression in the arterial system of lupus nephritis kidneys. The significance of this is unclear but could be related to heightened (gamma-interferon activation which may be a de novo phenomenon or result of T cell proliferation and activation in SLE.     

Dietary fat influences the expression of autoimmune disease in MRL/lpr/lpr mice.

Near-isocaloric diets with qualitative and quantitative differences in fat content have a profound influence on the manifestation and progression of the autoimmune syndrome that occurs in female MRL/lpr mice. In these animals, a high (9%) lipid intake resulted in a significantly higher mortality rate: 60% (saturated fat) and 75% (unsaturated fat) compared to 35% at 1 year for a group fed a diet low in fat. Furthermore, beginning at 7 months of age mice from both of the high fat diet groups exhibited a significantly higher incidence of proteinuria than mice in the low fat group. Immunologically, the group fed the high unsaturated fat diet had the highest incidence of anti-dsDNA autoantibodies, and the high saturated fat group had the poorest macrophage phagocytic function. The low fat diet preserved near 'normal' immune function in general, particularly IL-2 production. No significant differences were noted in either the production of rheumatoid factor or natural killer cell activity, irrespective of age or diet.     

Varying expression of major histocompatibility complex antigens on human renal endothelium and epithelium

Pre-anastomosis wedge biopsies from 14 cadaveric donor kidneys were examined for the expression of class I (HLA-ABC) and class II (HLA-DR) antigens in renal tissue. Two monoclonal antibodies to class I antigens and four to class II antigens were used in an indirect immunoperoxidase technique. Consistent expression of both antigens was demonstrated on the surface of glomerular, peritubular capillary and venous endothelial cells. Renal arteries contained only class I antigens. Proximal tubules contained varying amounts of each antigen in their cytoplasm. Sixteen human lymphocytotoxic allo-antisera showed marked variation in their ability to detect HLA antigens on the kidney. The selection of donors for recipients of renal allografts involves the complement-dependent cytotoxicity test and the failure of some lymphocytotoxic antisera to bind to the kidney indicates that some suitable patients may be incorrectly excluded. The use of a binding assay using an immunoperoxidase technique should be included in cross-match techniques particularly for patients who have high levels of circulating cytotoxic antibodies.     

Immunohistochemical location of major histocompatibility complex class 1 antigens in human placenta

Distribution of major histocompatibility complex class I antigens in the postpartum human placenta was studied by immunohistochemical method. Positive staining was observed in endotheliocyte cytoplasm in vessels of chorionic villi. The surface of trophoblast, cytotrophoblast, and connective tissue cells did not stain. These data indicate a peculiar «masking» of antigens essential for normal course of gestation.     

Varying expression of major histocompatibility complex antigens on human renal endothelium and epithelium.

Pre-anastomosis wedge biopsies from 14 cadaveric donor kidneys were examined for the expression of class I (HLA-ABC) and class II (HLA-DR) antigens in renal tissue. Two monoclonal antibodies to class I antigens and four to class II antigens were used in an indirect immunoperoxidase technique. Consistent expression of both antigens was demonstrated on the surface of glomerular, peritubular capillary and venous endothelial cells. Renal arteries contained only class I antigens. Proximal tubules contained varying amounts of each antigen in their cytoplasm. Sixteen human lymphocytotoxic allo-antisera showed marked variation in their ability to detect HLA antigens on the kidney. The selection of donors for recipients of renal allografts involves the complement-dependent cytotoxicity test and the failure of some lymphocytotoxic antisera to bind to the kidney indicates that some suitable patients may be incorrectly excluded. The use of a binding assay using an immunoperoxidase technique should be included in cross-match techniques particularly for patients who have high levels of circulating cytotoxic antibodies.     

TNFalpha inhibition in MRL/lpr mice ameliorates pulmonary but not renal disease

TNFalpha inhibition has a clearly beneficial effect in a number of arthritides and in Crohn's disease. The exact mechanism of action is uncertain with studies showing inhibition of chemokines, inhibition of adhesion molecule expression, and improved T-cell function. Unlike most therapeutic interventions for autoimmune disease, TNFalpha inhibition appears to act on specific pathologic processes. It is not known how wide-spread these TNFalpha-mediated pathologic processes are. Efforts to expand the use of TNFalpha inhibition have had notable successes but have been disappointing in other disorders. We hypothesized that TNFalpha-mediated pathologic processes might play a significant role in the end-organ effects seen in SLE. We modeled SLE by using MRL/lpr mice and treated with two types of TNFalpha inhibitor. Pulmonary disease was significantly improved in the treated groups compared to controls. In contrast, renal disease was unaffected suggesting that in lupus, where multiple organs are affected, different pathologic processes may be mediating the end-organ damage. This has important implications for designing therapeutics for SLE.     

MRL/lpr狼疮小鼠肾脏明胶酶表达随增龄变化及意义

目的 观察不同周龄MBL/lpr狼疮小鼠肾脏明胶酶的表达及其随增龄而发生的活性变化及意义。方法 取8、16与24周龄RMRL/lpr狼疮小鼠的肾组织进行常规病理检测。利用含有放射自显影的成像乳胶对冷冻肾组织切片进行原位明胶酶活性的检测;利用免疫组织化学检测肾脏明胶酶A与明胶酶B的酶B的蛋白表达变化,十二氨基磺酸钠-聚丙烯酰胺凝胶电泳（SDS-PACE）明胶酶谱法检测肾脏明胶酶A、B的活性变化。结果 8周龄狼疮小鼠肾组织吵仅在血管处检测到明胶酶的活性;16与24周龄狼疮小鼠肾小球内明胶酶的净活性明显增加。在肾小球以及肾小管间质上也可检测到明胶酶的活性,乙二胺四乙酸（EDTA）能够抑制肾脏明胶酶的活性,免疫组织化学与SDS-PAGE明胶酶谱法结果显示其肾组织中明胶酶A与明胶酶B的蛋白质表达及活性均明显增加。结论 明胶酶A、B在自发性狼疮小鼠肾炎中的表达及活化随增龄均明显增加,活化态的明胶酶可能在狼疮性肾炎细胞外基质重塑中发挥重要的作用。     

Genetic dissection of the complex pathological manifestations of collagen disease in MRL/lpr mice

An MRL strain of mice bearing a Fas-deletion mutant gene, lpr, MRL/MpJ-lpr/lpr (MRL/lpr) develops collagen disease involving vasculitis, glomerulonephritis, arthritis and sialoadenitis, each of which has been studied as a model for polyarteritis, lupus nephritis, rheumatoid arthritis and Sjögren’s syndrome, respectively. Development of such lesions seems dependent on host genetic background since the congenic C3H/HeJ-lpr/lpr (C3H/lpr) mice rarely develop them. To identify the gene loci affecting each lesion, a genetic dissection of these complex pathological manifestations was carried out. First, histopathological features in MRL/lpr, C3H/lpr, (MRL/lpr × C3H/lpr) F1 intercross, and MRL/lpr × (MRL/lpr × C3H/lpr) F1 backcross mice were analyzed. Genomic DNA of the backcross mice were subjected to association studies by Chi-squared analysis for determining which polymorphic microsatellite locus occurs at higher frequency among affected compared to unaffected individuals for each lesion. As a result, gene loci recessively associated with each lesion were mapped on different chromosomal positions. We concluded that each of these lesions in MRL/lpr mice is under the control of a different set of genes, suggesting that the complex pathological manifestations of collagen disease result from polygenic inheritance.     

Activation of genetically major histocompatibility complex (MHC) class II-deficient B lymphocytes

It has been suggested that MHC class II molecules can transduce signals required for B-cell activation. Enhancement or inhibition of B-cell stimulation by anti-MHC class II molecule antibodies has likewise been reported. The study of B cells from patients with a combined immune deficiency due to a defective expression of MHC class II genes provides a useful tool for approaching the functional role of B-cell HLA class II molecules. We have thus analyzed the specific and nonspecific, cognate and noncognate B-cell activation of genetically HLA class II-deficient lymphocytes. B lymphocytes from 14 tested patients were able to synthesize RNA following stimulation with ionomycin and phorbol myristate acetate or anti- antibodies and with mannan, a T cell-independent polysaccharidic antigen. They were also able to synthetize DNA following the addition of ionomycin and PMA or of anti- antibodies in the presence of recombinant interleukin 2. Pokeweed mitogen failed to induce B-lymphocyte terminal differentiation into immunoglobulin-producing cells in the presence of normal T lymphocytes, while a combination of anti-CD2 antibodies were capable of triggering IgG synthesis. B-cell activation, whatever the condition used, did not induce HLA class II expression. Mannan-specific T cell-dependent antibody production (IgM) was detected in 6 of 14 patients. Anti-influenza virus antibody production was always found absent. These results are compatible with the hypothesis that B-cell activation events that do not require a cognate interaction with T cells can occur in the absence of HLA class II molecule expression, while the absence of HLA class II molecule expression prevents T-B cognate interaction.     

The major histocompatibility complex (MHC) of the secondary transplant tissue donor influences the cross-reactivity of alloreactive memory cells

Memory cells are currently thought to be a major barrier to tolerance induction in transplantation. However, whether alloreactive memory cells resulting from a primary transplant have cross‐reactivity in a second transplant is unclear. Here, we used skin transplantation from BALB/c mice donors to presensitize C₅₇BL/6 (B6) mice. One month later, several strains of mice (including BALB/c, DBA/2, NOD, C3H and B6 mice) were chosen as donors to construct a memory model of heterotopic cardiac transplantation. The higher degree of major histocompatibility complex (MHC) mismatch to sensitizing MHC resulted in longer median survival times (MSTs, BALB/c 3.63 days versus C3H 6.08 days). After 3.5 days of cardiac transplantation, compared with the BALB/c and DBA/2 groups, in the groups of NOD and C3H, the infiltration of inflammatory cells in the grafts, the proportion and proliferation of memory cells in spleens and the function of allogeneic antibodies decreased significantly. The varying degrees of MHC mismatch between the primary and secondary donors influenced the intensity of alloreactive memory cell function, the higher degree of MHC mismatch resulted in better tolerance during secondary transplantation, and these may be related to the changed activation, proliferation and function of the alloreactive memory cells.     

Relationship between target antigens and major histocompatibility complex (MHC) class II genes in producing two pathogenic antibodies simultaneously

In this report,we present 15 patients with histological and immunopathologically proven pemphigus vulgaris (PV). After a mean of 80 months since the onset of disease, when evaluated serologically, they had antibodies typical of PV and pemphigoid (Pg). Similarly, 18 patients with bullous pemphigoid (BP) and mucous membrane pemphigoid (MMP) were diagnosed on the basis of histology and immunopathology.After a mean of 60 months since the onset of disease, when their sera were evaluated they were found to have Pg and PV autoantibodies. In both groups of patients the diseases were characterized by a chronic course, which included several relapses and recurrences and were non-responsive to conventional therapy. The major histocompatibility complex class II (MHC II) genes were studied in both groups of patients and phenotypes associated typically with them were observed. Hence, in 33 patients, two different pathogenic autoantibodies were detected simultaneously. The authors provide a computer model to show that each MHC II gene has relevant epitopes that recognize the antigens associated with both diseases. Using the databases in these computer models, the authors present the hypothesis that these two autoantibodies are produced simultaneously due to the phenomena of epitope spreading.     

Androgen control of autoimmune expression in lacrimal glands of MRL/Mp-lpr/lpr mice

The purpose of the present study was to determine, by utilizing an animal model of Sj?gren'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 Sj?gren's syndrome.     

Quantitative modifications of major histocompatibility complex (MHC) antigens induced by recombinant gamma interferon in two human breast cancer lines

H466-B and T47-D breast carcinoma cell lines were treated with recombinant gamma interferon (r gamma IFN) to study major histocompatibility complex (MHC) class I and class II antigen responses. Untreated H466-B cells released B2 microglobulin (B2M) into the culture medium and expressed B2M and class I heavy chain on 100% of the cells. The expression of class II antigens (DR) was limited to 8 +/- 4% of the cells. This subpopulation was isolated by cell sorting and labelled with 35S methionine. Protein extracts were immunoprecipitated with anti-DR antibody and subjected to two dimensional non-equilibrium pH gradient electrophoresis (2D-PAGE). A normal pattern of expression of invariant, alpha and beta chains was shown. The MHC antigenic expression of H466-B parental cell line was not modified by interferon treatment. Untreated T47-D cells did not release B2M into the culture medium, expressed B2M and class I heavy chain on 100% of the cells but did not express class II molecules using radio-immunoassay or 2D-PAGE. As early as 24 h after r gamma IFN addition, T47-D cells released B2M into the medium, B2M and class I heavy chain were significantly greater than that of untreated cells, and class II antigenic expression was found, all these in a dose dependent manner. 2D-PAGE analysis of class II antigens revealed the profile of human DR molecules but this expression seemed incomplete since only single alpha and beta spots were detected suggesting a possible defect in the sialilation of DR molecules. These results show a heterogeneity in MHC antigenic responses to r gamma IFN and suggest that synthetized class II molecules may be incompletely processed.     

Serum soluble MD-1 levels increase with disease progression in autoimmune prone MRL(lpr/lpr) mice

MD-1 is a secreted protein that forms a complex with radioprotective 105 (RP105) and this complex plays a crucial role in lipopolysaccharide (LPS) recognition by B cells. Disease progression is known to improve in RP105-deficient lupus-prone MRL(lpr/lpr) mice. Furthermore, a soluble form of the homologous MD-2 protein is present in the plasma of septic patients and can opsonize gram-negative bacteria in cooperation with Toll-like receptor (TLR) 4. We have now established a flow cytometry-based assay to detect the soluble form of murine MD-1 (sMD-1) and explored potential roles in autoimmunity. The assay was quantitative and validated with sera from MD-1-deficient mice. Interestingly, heat-inactivated murine serum diminished the ability of sMD-1 to bind RP105. The sMD-1 was secreted by bone marrow-derived macrophages from C57BL/6 mice. Autoimmune prone MRL(lpr/lpr) mice had higher levels of sMD-1 than control MRL(+/+) mice, and levels markedly increased with disease progression. Expression of MD-1 but not MD-2 mRNA increased with age in the liver and kidney of MRL(lpr/lpr) mice. Finally, immunohistochemical analyses revealed that MD-1 was present in infiltrated macrophages within perivascular lesions of the MRL(lpr/lpr) kidney. This correlation suggests that sMD-1 may contribute to pathogenesis in this autoimmune disease model.     

Ethanol impairs major histocompatibility complex (MHC) class II molecule-mediated but not MHC class I molecule-mediated T cell response in alcohol-consuming mice

The goal of this study was to determine whether alcohol affects alloantigen-induced proliferative and cytolytic activity of T cells in mice, and whether the altered immune response was in part due to a defect of IL-2 activity. The ability of spleen cells from individual alcohol-consuming C57BL/6 mice to generate allo-specific mixed lymphocyte response (MLR) and cytotoxic T lymphocyte (CTL) was compared to that of mice fed on an isocaloric maltose diet and regular diet. Allospecific MLR and CTL were generated by sensitizing spleen cells of C57BL/6 mice against spleen cells from BALB/c mice, and the allo-specific CTL activity was determined by the ability of the CTL to kill 51Cr-labeled P815 mastocytoma target cells. Our results showed that the allo-specific MLR of the responder cells from alcohol-consuming mice was significantly reduced (40% reduction, p<0.0 1), and the addition of exogenous interleukin 2 (IL-2) could not reverse the suppression of MLR induced by ethanol. However, our results clearly showed that ethanol has little suppressive effect on allo-reactive CTL of alcohol-consuming mice as compared to the alloreactivity of the control mice (P>0.05). Finally, we also demonstrated that ethanol did not impair the alloantigen-induced IL-2 production in the mixed lymphocyte cultures (P>0.1).     

Monophosphoryl lipid A (MPL) upregulates major histocompatibility complex (MHC) class I expression by increasing interferon-gamma (IFN-gamma)

Tumor immunity is primarily mediated by cells as CD8+ cytotoxic T lymphocytes (CTL) recognize tumor antigen by MHC class I molecules. But most tumors are associated with a decreased expression of MHC class I to escape the antitumor immunity of the host. Our previous data have demonstrated that MPL has an antitumor effect on metastatic lung cancer of B16 melanoma with enhancing cytotoxicity due to increase of IFN-gamma and IL-2, and decrease of IL-4, which indicates the stimulation of type 1 helper T cells (Th1). To determine the effects of MPL, IFN-gamma, TNF-alpha, and IL-1 alpha on MHC class I expression of B16 melanoma cells, we evaluated the expression of MHC class I molecules with treatments of MPL, IFN-gamma, TNF-alpha, and IL-1 alpha by flow cytometry. The supernatant of MPL-treated spleen cells in vitro upregulated the expression of MHC class I molecules of B16 melanoma cells compared to the control supernatant of spleen cells. The MHC class I expression of B16 melanoma cells treated with IFN-gamma, but not TNF-alpha or IL-1 alpha, increased in a time-dependent manner. In conclusion, MPL upregulated MHC class I expression of B16 melanoma cells by activating spleen cells via IFN-gamma. These data suggest that increased IFN-gamma by MPL is responsible for the upregulation of MHC class I expression to augment cytotoxicity. Therefore, we suggest that MPL could play an important role in immunotherapy.