Objective　To get the antigen of CD7.Methods　 The extracellular domain of human CD7 was cloned from a plasmid containing the full length of human CD7 cDNA and expressed in pinpoint-xa3 prokaryotic system. Results　 Analysis with SDS-PAGE and Western-blotting showed that the expressed protein could bind to the anti-CD7 mAb specifically and is about 30 000 u in molecular weight. Conclusion　 These results paved the way for preparing anti-CD7 engineering antibody.

Objective　To synthesize the artificial antigen methylparaoxon （M1600）.Methods　Methylparaoxon was reduced into amino-methylparaoxon by using acetic acid-zinc power-hydrochloric acid. Artificial antigens M1600-BSA， M1600-TTH　were synthesized by conjugating amino-methylparaoxon to bovine serum albumin （BSA）and tachypleus tridentatus hemocyanin （TTH）directly after diazotization.Results　 Rabbits had been immunized with M1600-BSA for 10 weeks， and the high titer and high specificity antiserum from those rabbits was testified by doubled agar gel diffusion and indirect ELISA．Conclusion　An artificial antigen was obtained successfully and this made it possible to establish the immunoassay of M1600.

Objective　To investigate the activation of human T cells with superantigen SEA. Methods　T cells proliferation, IL-2 production, DNA synthesis, cell phenotype and apoptosis induced by the SEA in the first or restimulation were detected. Results　 It was shown that 100 ng/mL was the optimal activation concentration, IL-2 production arrived at top level in the third day, SEA activated CD4+ and CD8+T with the same degree, T cells start apoptosis in response to SEA restimulation within 24 hours and apoptosis disappeared through addition of rhIL-2. Conclusions　 There were correlation between activation and SEA concentration or stimulation period； SEA activated both CD4+ and CD8+T cells without change the cell phenotype.

To investigate the role of CD45 protein tyrosine phosphatase in γδ T cell development,we exa-mined whether Vγ3 dendritic epidermal T cells (DETC),a subset of γδ T cells uniquely reside in the murine epidermis were altered in the CD45-gene -deficient mice.In situ immunolabelling on epidermal sheets demonstrsted that the CD45-deficient mice had a normal density and immunophenotype of Vγ3 DETC in comparison to the wild-type control mice.RT-PCR revealed that similar levels of Vγ3 TCR mRNA were present in the epidermis of both CD45-deficient mice and wild-type controls.FCM showed no significant difference in the proportion of Vγ3 T cells in the epidermal cells between the two genotypes.In addition, the frequency of Vγ2 T cells, another subset of γδT cells in lymph nodes was normal in CD45-deficient mice.These results indicate that althouh CD45 is crucial for the development of αβΤ cells,it might be not necessary for the thymic maturation of γδ T cells including Vγ3 DETC and Vγ2 T cells.

CD59 antigen is a widely expressed cell surface glycosylphosphatidyl-inositol (GPI) anchored glycoprotein.It acts as an inhibitor to the assembly of the membrane attack complex of homologous complement,binds to CD2,and also transduces activation signals with T cells.In this report,a 396bp DNA fragment was amplified by RT-PCR method from the total RNA of Jurkat cells.The fragment was cloned into pUC18 and pUC19 plas-mids,and further sequenced by Sanger′s-dideory-mediated chain termination.The results showed that this cDNA fragment included 384bp open reading fragment and its sequence was identical to the published sequence encoding human CD59 antigen.Furthermore,the cDNA of CD59 was subcloned into retroviral vector pLXSN and transfec-ted into packaging cell line PA317 to generate stable virus-producing cell lines.Then,mouse thymotase cell line EL-4 and fibroblasts cell line NIH3T3 were infected with the virus resulting in stable expression of CD59 on the cell surface.The transfected cells were tested for their susceptibility to human complement-mediated cytolysis.It was found that the transfected cells expressing CD59 antigen were far less susceptible than the controls,indicating that the gene for CD59 can be expressed in xenotypic cells stably to confer protection against human serum complement.

To seek the optimum experiment methods of animal immunization with HCV gene and to explore the effect on antibody responses in mice immunized by pCD-HCV1 recombinant in different administration, recombinant pCD-HCV1 was constructed by technique of molecular biology and was injected into muscles of Balb/c of mice with different times, routes and dosage of inoculations as well as different treatment. The results showed that the serum antibody level reached 0.183±0.06,0.428±0.05,0.707±0.08 and 0.773±0.07(OD410 value) respectively after recombinant pCD-HCV1(100μg/mouse) were injected into mice once, twice, three times and four times. The antibody level of mice (n＝12) with four times inoculation was the highest; pCD-HCV1 was perfused into stomach orally in mice or were into mice by i.p, s.c and i.m(100μg/mouse, three times) in different routes (n＝6), and the antibody levels were 0.138±0.05, 0.178±0.07, 0.233±0.08 and 0.691±0.05 respectively; after the mice (n＝8) were inoculated with the pCD-HCV1 of different dosage(10μg, 50μg and 100μg) the antibody levels of three groups were 0.11±0.09, 0.33±0.04, and 0.700±0.07, and the results showed a significant difference (P＜0.01); Mice was injected with procaine (100μl, 0.4mg) by i.m or s.c. Then pCD-HCV1 was injected into mice and antibody levels were higher than that of mice immunized directly with recombinant pCD-HCV1 of same dosage. The results may provide a reference data deserved for screening the optimum immunization method of development HCV-DNA-based vaccine in mice model.

Objective To investigate the influence of HLA immunogenic mismatching (IM) on acute rejection of renal transplants.Methods The function recovery time of renal allograft and the rate of acute rejection of 196 cases after cadaveric renal transplantation wereanalyzed. Results IM of HLA locus did not influence the function recovery time of the renal allograft. The IM of HLA-A locus did not increase the rate of allograft acute rejection whereas the HLA-B locus did and the HLA-DR increased the acute rejection rate significantly. Conclusion IM should not be ignored in HLA typing. HLA-B locus is related to the allograft acute rejection, while the IM of DR locus increasesthe allograft acute rejection rate significantly.

Objective　To study the role of bcl-2 and bax in the pathogenesis of hepatitis D. Methods　Expression of HDAg， bcl-2 and bax in liver specimens of 79 patients with hepatitis D were studied by immunohistochemistry technique. Meanwhile， the relationship between expression of HDAg and that of bcl-2／bax in liver specimens of patients were studied by double labelling technique and serial sections.Results　bcl-2 was mainly expressed in the cytoplasm of hepatocytes， bax mainly in the cytoplasm of hepatocytes and partly in the nucleus of hepatocytes， and HDAg mainly in the nucleus of hepatocytes. Most of HDAg and bax positive cells were distributed among infiltrating lymphocytes at the periportal region especially at the advancing edges of areas of “piecemeal necrosis”. Most of hepatocytes of bax positive was found to locate near to positive cells of HDAg， and there were positive correlations between degrees of bax expression and HDAg expression（P＜0.05）. Conclusions　The distribution and the expression of bax and HDAg are significantly correlated with the activity of inflammation and the severity of the liver damage， and HDV infection may induce the expression of bax in the hepatocytes，and hepatocyte apoptosis mediated by bcl-2／bax may play an important role in the liver cell injury by HDV infection.

Objective　 To investigated the possible roles of IL-18 in HBV infection, and the expression of IL-18 in the peripheral blood mononuclear cells (PBMC) of chronic hepatitis B. Methods 　In 15 cases of asymptomatic carriers, 30 cases of active and remissive phases of chronic hepatitis and 10 healthy individuals (as normal controls), IL-18 expression in PBMC were quantitatively analyzed with flow cytometric immunological method. The PBMC were separated routinely and stimulated with LPS (SIGMA) and Monensin (SIGMA) for 6 hours. Then the cells were harvested and fixed by PBS/4% paraformaldehyde. The treated cells were stored in liquid nitrogen for detection later. After immunologic stain, the expression of IL-18 in PBMC were examined by flow cytometry. Results　 ① IL-18 was the lowest in asymptomatic carriers. It was fewer in remissive phase than in normal controls (P＜0.01).There was no difference between active phase and normal controls(P=0.25).②Within the group of active phase, IL-18 was significantly different between each grade of inflammatory activity(P＜0.01),and correlated with serum ALT positively(r=0.63,P＜0.01). Conclusion　 IL-18 may relate to disease activity and the inflammation of liver.

Objective　To study the mucosa immune responses of gastric and intestinal mucosa in Balb／c mice administered orally with Hp sonicate and mucosal adjuvant（LT）．Methods　The changes of antigen specific AFC in gastric and intestinal mucosa were detected by ELISPOT assay． Results　The numbers of sIgA and IgG AFC rise significantly in PP and gastric mucosa， especially the numbers of sIgA-AFC， significant differences were observed between two immunized groups and the control． Conclusions　Locally synthesized specific sIgA antibodies contribute to immunity against gastric helicobacter infection．