To study the mechanism of infection of Epstein-Barr virus (EBV) in gastric carcinoma cells, the Akata and P3HR-1 strains of EBV were used as the test strains of viruses, and the signet ring cell line HSC-39 of gastric...To study the mechanism of infection of Epstein-Barr virus (EBV) in gastric carcinoma cells, the Akata and P3HR-1 strains of EBV were used as the test strains of viruses, and the signet ring cell line HSC-39 of gastric carcinoma cells was used as the target cells of infection. The virus-infected cell clones were isolated by limited dilution method. It was found that the EBV-encoded small RNA (EBER) could be detected in the infected cells. The Akata and P3HR-1 EBV infected parental cells and most of clones expressed EBNA1, but not EBNA2. Latent membrane protein (LMP-1) and LMP-2, and the Q promoter (p), but not the Cp/Wp for EBNA gene transcription was active in the infected parental cells as well as all the clones. Uninfected HSC-39 cells did not express CD21, however, Akata but not P3HR-1 EBV-infected clones expressed low level of CD21 mRNA. These results demonstrate that HSC-39 cells are susceptible to both EBV strains and EBV infects HSC-39 cells through the CD21-independent pathway. This study defines a signet ring type of gastric carcinoma cells line as a unique target cells for the study of EBV infection mechanism.展开更多
Complement receptor 2 （CR2/CD21） is predominantly expressed on the surface of mature B cells where it forms part of a coreceptor complex that functions, in part, to modulate B-cell receptor signal strength. CR2/CD21...Complement receptor 2 （CR2/CD21） is predominantly expressed on the surface of mature B cells where it forms part of a coreceptor complex that functions, in part, to modulate B-cell receptor signal strength. CR2/CD21 expression is tightly regulated throughout B-cell development such that CR2/CD21 cannot be detected on pre-B or terminally differentiated plasma cells. CR2/CD21 expression is upregulated at B-cell maturation and can be induced by IL-4 and CD40 signaling pathways. We have previously characterized elements in the proximal promoter and first intron of CR2/CD21 that are involved in regulating basal and tissue-specific expression. We now extend these analyses to the CR2/CD21 core promoter. We show that in mature B cells, CR2/~D21 transcription proceeds from a focused TSS regulated by a non-consensus TATA box, an initiator element and a downstream promoter element. Furthermore, occupancy of the general transcriptional machinery in pre-B versus mature B-cell lines correlate with CR2/CD21 expression level and indicate that promoter accessibility must switch from inactive to active during the transitional B-cell window.展开更多
Background:We aimed to evaluate the frequency of various types of B and T cells expressing CD21,CD32,and CD35 in multiple sclerosis(MS)clinical courses.Methods:Peripheral blood mononuclear cell from 30 MS patients(17 ...Background:We aimed to evaluate the frequency of various types of B and T cells expressing CD21,CD32,and CD35 in multiple sclerosis(MS)clinical courses.Methods:Peripheral blood mononuclear cell from 30 MS patients(17 relapsing remitting[RRMS],six secondary progressive[SPMS],and seven primary progressive MS[PPMS])and 18 healthy subjects were analyzed.All patients were in acute attack.Healthy controls were matched for age and gender ratio.The frequencies of various subsets of B and T cells were determined using flow cytometry.Results:The frequency of CD4^(+)T cells was lower in MS patients compared to control subjects(41.14±9.45%vs.46.88±6.98%,respectively,P<0.05).The CD32^(+)fraction of CD4^(+)T cells and the CD21^(+)fraction of CD8^(+)T cells were higher in MS patients(2.85±3.72%vs.1.06±0.62%for CD32^(+)CD4^(+)T cells,2.71±1.86%vs.1.16±0.99%for CD21^(+)CD8^(+)T cells in MS patients and control subjects,respectively,P<0.05).After dividing subjects by type of MS course,higher values of these two T cell subsets were found in SPMS patients compared to control subjects(P<0.05).Further,RRMS patients had lower levels of CD32^(+)CD4^(+)T cells than SPMS patients and also they had lower levels of CD32^(+)CD8^(+)T cells than PPMS patients(P<0.05).However,neither the expression of CD35 on T cells nor the various B cell subsets were statistically different between the compared groups.Conclusions:Our findings demonstrate that T cell subsets expressing CD21 and CD32 may differ with respect to the presence or clinical forms of MS disease.By contrast,CD35^(+)T cells and different subsets of B cells are not altered in various MS clinical courses.展开更多
文摘To study the mechanism of infection of Epstein-Barr virus (EBV) in gastric carcinoma cells, the Akata and P3HR-1 strains of EBV were used as the test strains of viruses, and the signet ring cell line HSC-39 of gastric carcinoma cells was used as the target cells of infection. The virus-infected cell clones were isolated by limited dilution method. It was found that the EBV-encoded small RNA (EBER) could be detected in the infected cells. The Akata and P3HR-1 EBV infected parental cells and most of clones expressed EBNA1, but not EBNA2. Latent membrane protein (LMP-1) and LMP-2, and the Q promoter (p), but not the Cp/Wp for EBNA gene transcription was active in the infected parental cells as well as all the clones. Uninfected HSC-39 cells did not express CD21, however, Akata but not P3HR-1 EBV-infected clones expressed low level of CD21 mRNA. These results demonstrate that HSC-39 cells are susceptible to both EBV strains and EBV infects HSC-39 cells through the CD21-independent pathway. This study defines a signet ring type of gastric carcinoma cells line as a unique target cells for the study of EBV infection mechanism.
文摘Complement receptor 2 （CR2/CD21） is predominantly expressed on the surface of mature B cells where it forms part of a coreceptor complex that functions, in part, to modulate B-cell receptor signal strength. CR2/CD21 expression is tightly regulated throughout B-cell development such that CR2/CD21 cannot be detected on pre-B or terminally differentiated plasma cells. CR2/CD21 expression is upregulated at B-cell maturation and can be induced by IL-4 and CD40 signaling pathways. We have previously characterized elements in the proximal promoter and first intron of CR2/CD21 that are involved in regulating basal and tissue-specific expression. We now extend these analyses to the CR2/CD21 core promoter. We show that in mature B cells, CR2/~D21 transcription proceeds from a focused TSS regulated by a non-consensus TATA box, an initiator element and a downstream promoter element. Furthermore, occupancy of the general transcriptional machinery in pre-B versus mature B-cell lines correlate with CR2/CD21 expression level and indicate that promoter accessibility must switch from inactive to active during the transitional B-cell window.
文摘Background:We aimed to evaluate the frequency of various types of B and T cells expressing CD21,CD32,and CD35 in multiple sclerosis(MS)clinical courses.Methods:Peripheral blood mononuclear cell from 30 MS patients(17 relapsing remitting[RRMS],six secondary progressive[SPMS],and seven primary progressive MS[PPMS])and 18 healthy subjects were analyzed.All patients were in acute attack.Healthy controls were matched for age and gender ratio.The frequencies of various subsets of B and T cells were determined using flow cytometry.Results:The frequency of CD4^(+)T cells was lower in MS patients compared to control subjects(41.14±9.45%vs.46.88±6.98%,respectively,P<0.05).The CD32^(+)fraction of CD4^(+)T cells and the CD21^(+)fraction of CD8^(+)T cells were higher in MS patients(2.85±3.72%vs.1.06±0.62%for CD32^(+)CD4^(+)T cells,2.71±1.86%vs.1.16±0.99%for CD21^(+)CD8^(+)T cells in MS patients and control subjects,respectively,P<0.05).After dividing subjects by type of MS course,higher values of these two T cell subsets were found in SPMS patients compared to control subjects(P<0.05).Further,RRMS patients had lower levels of CD32^(+)CD4^(+)T cells than SPMS patients and also they had lower levels of CD32^(+)CD8^(+)T cells than PPMS patients(P<0.05).However,neither the expression of CD35 on T cells nor the various B cell subsets were statistically different between the compared groups.Conclusions:Our findings demonstrate that T cell subsets expressing CD21 and CD32 may differ with respect to the presence or clinical forms of MS disease.By contrast,CD35^(+)T cells and different subsets of B cells are not altered in various MS clinical courses.
