The worldwide declines in amphibian populations have largely been caused by infectious fungi and bacteria. Given that vertebrate immunity against these extracellular pathogens is primarily functioned by the major hist...The worldwide declines in amphibian populations have largely been caused by infectious fungi and bacteria. Given that vertebrate immunity against these extracellular pathogens is primarily functioned by the major histocompatibility complex（MHC） class Ⅱ molecules, the characterization and the evolution of amphibian MHC class Ⅱ genes have attracted increasing attention. The polymorphism of MHC class Ⅱ genes was found to be correlated with susceptibility to fungal pathogens in many amphibian species, suggesting the importance of studies on MHC class Ⅱ genes for amphibians. However, such studies on MHC class Ⅱ gene evolution have rarely been conducted on amphibians in China. In this study, we chose Omei treefrog（Rhacophorus omeimontis）, which lived moist environments easy for breeding bacteria, to study the polymorphism of its MHC class Ⅱ genes and the underlying evolutionary mechanisms. We amplified the entire MHC class ⅡB exon 2 sequence in the R. omeimontis using newly designed primers. We detected 102 putative alleles in 146 individuals. The number of alleles per individual ranged from one to seven, indicating that there are at least four loci containing MHC class ⅡB genes in R. omeimontis. The allelic polymorphism estimated from the 102 alleles in R. omeimontis was not high compared to that estimated in other anuran species. No significant gene recombination was detected in the 102 MHC class ⅡB exon 2 sequences. In contrast, both gene duplication and balancing selection greatly contributed to the variability in MHC class ⅡB exon 2 sequences of R. omeimontis. This study lays the groundwork for the future researches to comprehensively analyze the evolution of amphibian MHC genes and to assess the role of MHC gene polymorphisms in resistance against extracellular pathogens for amphibians in China.展开更多
Purpose:To investigate the density, distribution and morphology of macrophages and MHC class II -positive dendritic cells in the iris and ciliary body of lewis rats. Methods:Immunohistochemistry was performed using mo...Purpose:To investigate the density, distribution and morphology of macrophages and MHC class II -positive dendritic cells in the iris and ciliary body of lewis rats. Methods:Immunohistochemistry was performed using monoclonal antibodies specific to monocytes and macrophages (ED1,ED2) and MHC class II -positive cells (OX6) on wholemounts of the iris-ciliary body complex isolated form normal lewis rats.Results:A well developed network of macrophages was present in the iris and ciliary body of normal lewis rats. These cells, morphologically displaying dendriti-form or pleiomorphic appearance, were more densely arranged in mid-iris (950 + 189 cells/mm2) than in iris base (482 ± 78 cells/mm2) and pupil margin (595 ± 92 cells/mm2). A similar network of MHC class II -positive cells with a cell density 452 ± 78 cells/mm2 was almost uniformly distributed in the iris of normal lewis rats.Conclusions : A network of macrophages and MHC class II -positive cells was established in the iris and ciliary body of展开更多
AIM: To investigate the role of MHC class Ⅱ in the modulation of gastric epithelial cell apoptosis induced by H pylori infection.METHODS: After stimulating a human gastric epithelial cell line with bacteria or agonis...AIM: To investigate the role of MHC class Ⅱ in the modulation of gastric epithelial cell apoptosis induced by H pylori infection.METHODS: After stimulating a human gastric epithelial cell line with bacteria or agonist antibodies specifi c for MHC class Ⅱ and CD95, the quantitation of apoptotic and anti-apoptotic events, including caspase activation, BCL-2 activation, and FADD recruitment, was performed with a ? uorometric assay, a cytometric bead array, and confocal microscopy, respectively.RESULTS: Pretreatment of N87 cells with the anti-MHC class Ⅱ IgM antibody RFD1 resulted in a reduction in global caspase activation at 24 h of H pylori infection. When caspase 3 activation was specifically measured, crosslinking of MHC class Ⅱ resulted in a marked re-duced caspase activation, while simple ligation of MHC class Ⅱ did not. Crosslinking of MHC class Ⅱ also re-sulted in an increased activation of the anti-apoptosis molecule BCL-2 compared to simple ligation. Confocal microscope analysis demonstrated that the pretreatment of gastric epithelial cells with a crosslinking anti-MHC class Ⅱ IgM blocked the recruitment of FADD to the cell surface.CONCLUSION: The results presented here demonstrate that the ability of MHC class Ⅱ to modulate gastric epi-thelial apoptosis is at least partially dependent on its crosslinking. Furthermore, while previous research has demonstrated that MHC class Ⅱ signaling can be pro-apoptotic during extended ligation, we have shown that the crosslinking of this molecule has anti-apoptotic ef-fects during the earlier time points of H pylori infection. This effect is possibly mediated by the ability of MHC class Ⅱ to modulate the activation of the pro-apoptotic receptor Fas by blocking the recruitment of the accessory molecule FADD, and this delay in apoptosis induction could allow for prolonged cytokine secretion by H pylori-infected gastric epithelial cells.展开更多
AIM: To investigate the relationship between the polymorphism of class Ⅱ transactivator (CⅡTA) gene promoters and chronic hepatitis B (CHB).METHODS: Genomic DNA was prepared from peripheral blood leukocytes. Promote...AIM: To investigate the relationship between the polymorphism of class Ⅱ transactivator (CⅡTA) gene promoters and chronic hepatitis B (CHB).METHODS: Genomic DNA was prepared from peripheral blood leukocytes. Promoters Ⅰ, Ⅲ and Ⅳ of gene were analyzed respectively with polymerase chain reaction single strand conformation polymorphism (PCR-SSCP) in 65 patients with CHB, 26 patients with acute hepatitis B (AHB) and 85 normal controls.RESULTS: No abnormal migration was found in PCR-SSCP analysis of the three promoters in the three groups. Also,no sequential difference was observed at the three promoters among the CHB patients, AHB patients and normal controls.CONCLUSION: No polymorphism in promoters Ⅰ, Ⅲ and Ⅳ of CⅡTA gene exists in CHB patients, ABH patients and normal controls, suggesting that the promoter of CⅡTA gene might be a conserved domain.展开更多
The major histocompatibility complex(MHC) genes play pivotal roles in the immune system of vertebrates against antigens.They are also significant indicators of genetic structure,and are vital to species-level populati...The major histocompatibility complex(MHC) genes play pivotal roles in the immune system of vertebrates against antigens.They are also significant indicators of genetic structure,and are vital to species-level population viability analyses and disease risk assessments.In this study,two DRA and two DQA sequences were isolated from Hainan Eld's deer(Cervus eldi hainanus) using rapid amplification of cDNA ends(RACE) and single-strand conformation polymorphism-heteroduplex(SSCP-HD) analysis.Nucleotide sequence analysis revealed large differences between the two DQA sequences,especially in their exon 2 regions,but only minimal differences between the variants of the DRA gene.Comparison of the predicted amino acid sequences of the Ceel-MHC class Ⅱ A variants with those from six other species revealed that these molecules share high homology among ruminants.A phylogenetic tree of four class Ⅱ A sequences from Hainan Eld's deer and the other species placed the newly identified DQA and DRA genes on two distinct branches(100%-supportively),and further divided the two DQA sequences into 98%-supportive DQA1 and 99%-supportive DQA2 clusters,respectively.Therefore,this study identified monomorphic Ceel-DQA1 and Ceel-DQA2 genes,and one dimorphic Ceel-DRA gene from Hainan Eld's deer.展开更多
The role of MHC class Ⅱ transactivator (CⅡTA) in constitutive or IFN-γ inducible expression of HLA molecules in human malignant hematological cell lines was investigated. The expression of HLA molecules and CⅡTA ...The role of MHC class Ⅱ transactivator (CⅡTA) in constitutive or IFN-γ inducible expression of HLA molecules in human malignant hematological cell lines was investigated. The expression of HLA molecules and CⅡTA protein was detected by Western blot, immunohistochemistry and flow cytometry. The expression of CⅡTA gene was determined by RT-PCR. The capability of peripheral blood T cell reaction stimulated by tumor cells was monitored by mixed lymphocyte reaction. It was found that the HLAⅡ-positive tumor cells expressed the CⅡ TA quite well, and the expression of HLAⅠ+Ⅱ was increased in the tumor cells with constitutive or inducible expression of CⅡ TA after induced by IFN-γ. The tumor cells which did not express CⅡ TA after induced by IFN- γ were not response to the expression of HLAⅡ promoted by IFN- γ. It suggests a correlation between the inability of some malignant hematological cell lines in response to IFN-γ for HLA expression and the deficiency in the inducible expression of CⅡTA, indicating CⅡ TA might take part in the regulation of HLA Ⅰ+Ⅱ expression in the tumor cells, which might play an important role in tumor immunologic escape.展开更多
This word was supported by grant from Military Medical Research Foundation of china (96z032). ** To whom correspondence and requests for reprints should be addressed. This is one of papers of the special ...This word was supported by grant from Military Medical Research Foundation of china (96z032). ** To whom correspondence and requests for reprints should be addressed. This is one of papers of the special issue on gene therapy research (Chin J Cancer Res Vol. 9 No. 4 December, 1997). In order to investigate the antitumor effects of the in vivo G CSF gene therapy mediated by liposome and its mechanisms, human G CSF gene was encapsulated into liposome and was directly injected into tumor mass of C 26 colon adenocarcinoma bearing mice. After direct intratumoral injection of liposome encapsulated G CSF DNA, the subcutaneous tumor growth was dramatically inhibited and the survival time was prolonged signifi cantly. Tumor regression could be observed in about 30% of C 26 bearing mice. By the analysis of the antitumor mechanisms, we found that anti G 418 (600ug/ml) clone could be selected from the tumor cells freshly separated from the treated C 26 tumor mass, and secretion of G CSF in the supernatant could be detected. Northern blot also confirmed the expression of hG CSF by the tumor cells. Higher expressions of MHC class I(H 2k d) molecule and ICAM 1 on the tumor cells could be observed. The results demonstrated that liposome can effectively transfect G CSF gene into tumor cells in situ , and then increase the immunogenicity of the tumor cells which may contribute to the activation of the local antitumor immune responses effectively.展开更多
为进一步丰富鱼类MHC class Ⅱ基因的研究,同时也为进一步探讨低磷饲料中添加维生素D3对鱼类免疫功能可能的影响,实验利用RACE(Rapid-amplification of c DNA ends)即c DNA末端快速扩增技术,成功克隆出黄颡鱼(Pelteobagrus fulvidraco)...为进一步丰富鱼类MHC class Ⅱ基因的研究,同时也为进一步探讨低磷饲料中添加维生素D3对鱼类免疫功能可能的影响,实验利用RACE(Rapid-amplification of c DNA ends)即c DNA末端快速扩增技术,成功克隆出黄颡鱼(Pelteobagrus fulvidraco)主要组织相容性复合体(Major histocompatibility complex,MHC)class Ⅱ抗原基因,全长1074 bp,其中ORF(Open reading frame)708 bp,编码236个氨基酸,5′UTR(5′端非翻译区)78 bp,3′UTR(3′端非翻译区)259 bp。进行氨基酸序列比对分析得到:黄颡鱼MHC class Ⅱ基因ORF氨基酸序列与长吻逘(Leiocassis longirostris)的氨基酸序列相似度最高为69.5%,与锦鲤(Cyprinus carpio)的氨基酸序列相似度最低为50.4%。利用q PCR对黄颡鱼MHC class Ⅱ基因进行组织表达分析,结果表明MHC class Ⅱ在小肠、肝脏、鳃中表达较高;在肌肉、鳍条中表达较低;而在肾、脾脏、脑、头肾中表达量极低(几乎检测不到)。在低磷饲料中添加维生素D3显著诱导了该基因的上调表达。研究结果展示了黄颡鱼MHC class Ⅱ抗原基因的分子结构、组织表达以及维生素D3的作用,在降低磷排放的同时,为今后黄颡鱼免疫抗病及分子选育等方向的深入研究及免疫型饲料的使用奠定了基础。展开更多
AIM: To investigate the role of MHC classⅡin the modulation of gastric epithelial cell apoptosis induced by H pylon infection. METHODS: After stimulating a human gastric epithelial cell line with bacteria or agonist ...AIM: To investigate the role of MHC classⅡin the modulation of gastric epithelial cell apoptosis induced by H pylon infection. METHODS: After stimulating a human gastric epithelial cell line with bacteria or agonist antibodies specific for MHC classⅡand CD95, the quantitation of apoptotic and anti-apoptotic events, including caspase activation, BCL-2 activation, and FADD recruitment, was performed with a fluorometric assay, a cytometric bead array, and confocal microscopy, respectively. RESULTS: Pretreatment of N87 cells with the anti-MHC classⅡIgM antibody RFD1 resulted in a reduction in global caspase activation at 24 h of H pylori infection. When caspase 3 activation was specifically measured, crosslinking of MHC class n resulted in markedly reduced caspase activation, while simple ligation of MHC classⅡdid not. Crosslinking of MHC class n also resulted in an increased activation of the anti-apoptosis molecule BCL-2 compared to simple ligation. Confocal microscope analysis demonstrated that the pretreatment of gastric epithelial cells with a crosslinking anti-MHC classⅡIgM blocked the recruitment of FADD to the cell surface. CONCLUSION: The ability of MHC class n to modulate gastric epithelial apoptosis is at least partially dependent on its crosslinking. The crosslinking of this molecule has anti-apoptotic effects during the earlier time points of H pylori infection. This effect is possibly mediated by the ability of MHC classⅡto modulate the activation of the pro-apoptotic receptor Fas by blocking the recruitment of the accessory molecule FADD, and this delay in apoptosis induction could allow for prolonged cytokine secretion by H pylori-infected gastric epithelial cells.展开更多
We investigated the predicted function of proteins eluded from human MHC class Ⅱ molecules.Peptides that are presented by MHC class Ⅱ were obtained from the SYFPEITHI database and the corresponding proteins were fou...We investigated the predicted function of proteins eluded from human MHC class Ⅱ molecules.Peptides that are presented by MHC class Ⅱ were obtained from the SYFPEITHI database and the corresponding proteins were found in the SWISSPROT database.The functions of these proteins were predicted using the protfun server.Our analysis showed that human proteins presented by MHC class Ⅱ molecules are likely to be in the cell envelope,be a receptor or involved in immune responses.Presented proteins from bacteria and virus,on the other hand,are more likely to be involved in regulatory functions,translation,transcription as well as replication.These results can lead to better understanding the autoimmunity and the response to infections.Cellular & Molecular Immunology.2005; 2(1):49-56.展开更多
基金supported by the National Natural Science Foundation of China(No.31201713,No.31270425 and No.31470442)
文摘The worldwide declines in amphibian populations have largely been caused by infectious fungi and bacteria. Given that vertebrate immunity against these extracellular pathogens is primarily functioned by the major histocompatibility complex（MHC） class Ⅱ molecules, the characterization and the evolution of amphibian MHC class Ⅱ genes have attracted increasing attention. The polymorphism of MHC class Ⅱ genes was found to be correlated with susceptibility to fungal pathogens in many amphibian species, suggesting the importance of studies on MHC class Ⅱ genes for amphibians. However, such studies on MHC class Ⅱ gene evolution have rarely been conducted on amphibians in China. In this study, we chose Omei treefrog（Rhacophorus omeimontis）, which lived moist environments easy for breeding bacteria, to study the polymorphism of its MHC class Ⅱ genes and the underlying evolutionary mechanisms. We amplified the entire MHC class ⅡB exon 2 sequence in the R. omeimontis using newly designed primers. We detected 102 putative alleles in 146 individuals. The number of alleles per individual ranged from one to seven, indicating that there are at least four loci containing MHC class ⅡB genes in R. omeimontis. The allelic polymorphism estimated from the 102 alleles in R. omeimontis was not high compared to that estimated in other anuran species. No significant gene recombination was detected in the 102 MHC class ⅡB exon 2 sequences. In contrast, both gene duplication and balancing selection greatly contributed to the variability in MHC class ⅡB exon 2 sequences of R. omeimontis. This study lays the groundwork for the future researches to comprehensively analyze the evolution of amphibian MHC genes and to assess the role of MHC gene polymorphisms in resistance against extracellular pathogens for amphibians in China.
基金a grant from Pubic Health Ministry of ChinaNatural Science Fundation of Guangdong Province
文摘Purpose:To investigate the density, distribution and morphology of macrophages and MHC class II -positive dendritic cells in the iris and ciliary body of lewis rats. Methods:Immunohistochemistry was performed using monoclonal antibodies specific to monocytes and macrophages (ED1,ED2) and MHC class II -positive cells (OX6) on wholemounts of the iris-ciliary body complex isolated form normal lewis rats.Results:A well developed network of macrophages was present in the iris and ciliary body of normal lewis rats. These cells, morphologically displaying dendriti-form or pleiomorphic appearance, were more densely arranged in mid-iris (950 + 189 cells/mm2) than in iris base (482 ± 78 cells/mm2) and pupil margin (595 ± 92 cells/mm2). A similar network of MHC class II -positive cells with a cell density 452 ± 78 cells/mm2 was almost uniformly distributed in the iris of normal lewis rats.Conclusions : A network of macrophages and MHC class II -positive cells was established in the iris and ciliary body of
基金Supported by the National Institutes of Health Grants DK50669, DK56338 and National Institutes of Health T32 AI007536-06 Training Grant
文摘AIM: To investigate the role of MHC class Ⅱ in the modulation of gastric epithelial cell apoptosis induced by H pylori infection.METHODS: After stimulating a human gastric epithelial cell line with bacteria or agonist antibodies specifi c for MHC class Ⅱ and CD95, the quantitation of apoptotic and anti-apoptotic events, including caspase activation, BCL-2 activation, and FADD recruitment, was performed with a ? uorometric assay, a cytometric bead array, and confocal microscopy, respectively.RESULTS: Pretreatment of N87 cells with the anti-MHC class Ⅱ IgM antibody RFD1 resulted in a reduction in global caspase activation at 24 h of H pylori infection. When caspase 3 activation was specifically measured, crosslinking of MHC class Ⅱ resulted in a marked re-duced caspase activation, while simple ligation of MHC class Ⅱ did not. Crosslinking of MHC class Ⅱ also re-sulted in an increased activation of the anti-apoptosis molecule BCL-2 compared to simple ligation. Confocal microscope analysis demonstrated that the pretreatment of gastric epithelial cells with a crosslinking anti-MHC class Ⅱ IgM blocked the recruitment of FADD to the cell surface.CONCLUSION: The results presented here demonstrate that the ability of MHC class Ⅱ to modulate gastric epi-thelial apoptosis is at least partially dependent on its crosslinking. Furthermore, while previous research has demonstrated that MHC class Ⅱ signaling can be pro-apoptotic during extended ligation, we have shown that the crosslinking of this molecule has anti-apoptotic ef-fects during the earlier time points of H pylori infection. This effect is possibly mediated by the ability of MHC class Ⅱ to modulate the activation of the pro-apoptotic receptor Fas by blocking the recruitment of the accessory molecule FADD, and this delay in apoptosis induction could allow for prolonged cytokine secretion by H pylori-infected gastric epithelial cells.
基金Supported by the National Natural Science Foundation of China,No. 30270597
文摘AIM: To investigate the relationship between the polymorphism of class Ⅱ transactivator (CⅡTA) gene promoters and chronic hepatitis B (CHB).METHODS: Genomic DNA was prepared from peripheral blood leukocytes. Promoters Ⅰ, Ⅲ and Ⅳ of gene were analyzed respectively with polymerase chain reaction single strand conformation polymorphism (PCR-SSCP) in 65 patients with CHB, 26 patients with acute hepatitis B (AHB) and 85 normal controls.RESULTS: No abnormal migration was found in PCR-SSCP analysis of the three promoters in the three groups. Also,no sequential difference was observed at the three promoters among the CHB patients, AHB patients and normal controls.CONCLUSION: No polymorphism in promoters Ⅰ, Ⅲ and Ⅳ of CⅡTA gene exists in CHB patients, ABH patients and normal controls, suggesting that the promoter of CⅡTA gene might be a conserved domain.
基金supported by the National Natural Science Foundation of China (30970426)a special grant from the State Forestry Administration of Chinathe Fundamental Research Funds for the Central Universities of China
文摘The major histocompatibility complex(MHC) genes play pivotal roles in the immune system of vertebrates against antigens.They are also significant indicators of genetic structure,and are vital to species-level population viability analyses and disease risk assessments.In this study,two DRA and two DQA sequences were isolated from Hainan Eld's deer(Cervus eldi hainanus) using rapid amplification of cDNA ends(RACE) and single-strand conformation polymorphism-heteroduplex(SSCP-HD) analysis.Nucleotide sequence analysis revealed large differences between the two DQA sequences,especially in their exon 2 regions,but only minimal differences between the variants of the DRA gene.Comparison of the predicted amino acid sequences of the Ceel-MHC class Ⅱ A variants with those from six other species revealed that these molecules share high homology among ruminants.A phylogenetic tree of four class Ⅱ A sequences from Hainan Eld's deer and the other species placed the newly identified DQA and DRA genes on two distinct branches(100%-supportively),and further divided the two DQA sequences into 98%-supportive DQA1 and 99%-supportive DQA2 clusters,respectively.Therefore,this study identified monomorphic Ceel-DQA1 and Ceel-DQA2 genes,and one dimorphic Ceel-DRA gene from Hainan Eld's deer.
文摘The role of MHC class Ⅱ transactivator (CⅡTA) in constitutive or IFN-γ inducible expression of HLA molecules in human malignant hematological cell lines was investigated. The expression of HLA molecules and CⅡTA protein was detected by Western blot, immunohistochemistry and flow cytometry. The expression of CⅡTA gene was determined by RT-PCR. The capability of peripheral blood T cell reaction stimulated by tumor cells was monitored by mixed lymphocyte reaction. It was found that the HLAⅡ-positive tumor cells expressed the CⅡ TA quite well, and the expression of HLAⅠ+Ⅱ was increased in the tumor cells with constitutive or inducible expression of CⅡ TA after induced by IFN-γ. The tumor cells which did not express CⅡ TA after induced by IFN- γ were not response to the expression of HLAⅡ promoted by IFN- γ. It suggests a correlation between the inability of some malignant hematological cell lines in response to IFN-γ for HLA expression and the deficiency in the inducible expression of CⅡTA, indicating CⅡ TA might take part in the regulation of HLA Ⅰ+Ⅱ expression in the tumor cells, which might play an important role in tumor immunologic escape.
文摘This word was supported by grant from Military Medical Research Foundation of china (96z032). ** To whom correspondence and requests for reprints should be addressed. This is one of papers of the special issue on gene therapy research (Chin J Cancer Res Vol. 9 No. 4 December, 1997). In order to investigate the antitumor effects of the in vivo G CSF gene therapy mediated by liposome and its mechanisms, human G CSF gene was encapsulated into liposome and was directly injected into tumor mass of C 26 colon adenocarcinoma bearing mice. After direct intratumoral injection of liposome encapsulated G CSF DNA, the subcutaneous tumor growth was dramatically inhibited and the survival time was prolonged signifi cantly. Tumor regression could be observed in about 30% of C 26 bearing mice. By the analysis of the antitumor mechanisms, we found that anti G 418 (600ug/ml) clone could be selected from the tumor cells freshly separated from the treated C 26 tumor mass, and secretion of G CSF in the supernatant could be detected. Northern blot also confirmed the expression of hG CSF by the tumor cells. Higher expressions of MHC class I(H 2k d) molecule and ICAM 1 on the tumor cells could be observed. The results demonstrated that liposome can effectively transfect G CSF gene into tumor cells in situ , and then increase the immunogenicity of the tumor cells which may contribute to the activation of the local antitumor immune responses effectively.
文摘为进一步丰富鱼类MHC class Ⅱ基因的研究,同时也为进一步探讨低磷饲料中添加维生素D3对鱼类免疫功能可能的影响,实验利用RACE(Rapid-amplification of c DNA ends)即c DNA末端快速扩增技术,成功克隆出黄颡鱼(Pelteobagrus fulvidraco)主要组织相容性复合体(Major histocompatibility complex,MHC)class Ⅱ抗原基因,全长1074 bp,其中ORF(Open reading frame)708 bp,编码236个氨基酸,5′UTR(5′端非翻译区)78 bp,3′UTR(3′端非翻译区)259 bp。进行氨基酸序列比对分析得到:黄颡鱼MHC class Ⅱ基因ORF氨基酸序列与长吻逘(Leiocassis longirostris)的氨基酸序列相似度最高为69.5%,与锦鲤(Cyprinus carpio)的氨基酸序列相似度最低为50.4%。利用q PCR对黄颡鱼MHC class Ⅱ基因进行组织表达分析,结果表明MHC class Ⅱ在小肠、肝脏、鳃中表达较高;在肌肉、鳍条中表达较低;而在肾、脾脏、脑、头肾中表达量极低(几乎检测不到)。在低磷饲料中添加维生素D3显著诱导了该基因的上调表达。研究结果展示了黄颡鱼MHC class Ⅱ抗原基因的分子结构、组织表达以及维生素D3的作用,在降低磷排放的同时,为今后黄颡鱼免疫抗病及分子选育等方向的深入研究及免疫型饲料的使用奠定了基础。
基金the National Institutes of Health Grants DK50669 and DK56338. EB was a recipient of a fellowship under National Institutes of Health T32 AI007536-06 Training Grant
文摘AIM: To investigate the role of MHC classⅡin the modulation of gastric epithelial cell apoptosis induced by H pylon infection. METHODS: After stimulating a human gastric epithelial cell line with bacteria or agonist antibodies specific for MHC classⅡand CD95, the quantitation of apoptotic and anti-apoptotic events, including caspase activation, BCL-2 activation, and FADD recruitment, was performed with a fluorometric assay, a cytometric bead array, and confocal microscopy, respectively. RESULTS: Pretreatment of N87 cells with the anti-MHC classⅡIgM antibody RFD1 resulted in a reduction in global caspase activation at 24 h of H pylori infection. When caspase 3 activation was specifically measured, crosslinking of MHC class n resulted in markedly reduced caspase activation, while simple ligation of MHC classⅡdid not. Crosslinking of MHC class n also resulted in an increased activation of the anti-apoptosis molecule BCL-2 compared to simple ligation. Confocal microscope analysis demonstrated that the pretreatment of gastric epithelial cells with a crosslinking anti-MHC classⅡIgM blocked the recruitment of FADD to the cell surface. CONCLUSION: The ability of MHC class n to modulate gastric epithelial apoptosis is at least partially dependent on its crosslinking. The crosslinking of this molecule has anti-apoptotic effects during the earlier time points of H pylori infection. This effect is possibly mediated by the ability of MHC classⅡto modulate the activation of the pro-apoptotic receptor Fas by blocking the recruitment of the accessory molecule FADD, and this delay in apoptosis induction could allow for prolonged cytokine secretion by H pylori-infected gastric epithelial cells.
文摘We investigated the predicted function of proteins eluded from human MHC class Ⅱ molecules.Peptides that are presented by MHC class Ⅱ were obtained from the SYFPEITHI database and the corresponding proteins were found in the SWISSPROT database.The functions of these proteins were predicted using the protfun server.Our analysis showed that human proteins presented by MHC class Ⅱ molecules are likely to be in the cell envelope,be a receptor or involved in immune responses.Presented proteins from bacteria and virus,on the other hand,are more likely to be involved in regulatory functions,translation,transcription as well as replication.These results can lead to better understanding the autoimmunity and the response to infections.Cellular & Molecular Immunology.2005; 2(1):49-56.
