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BACKGROUND:Various surface modification techniques have been used to improve the bioactivity of titaniumimplant in vivo. OBJECTIVE:To investigate the effects of enamel matrix proteins (EMPs) on the growth of apatite coatings on dual thermo-etching treated pure titanium. METHODS:EMPs were extracted from porcine tooth germs and then were identified. Dual thermo-etching was applied to treat titanium samples fol owing polished, and then immersed in a blank simulated body fluid supersaturated calcification solution (control group) or supersaturated calcification solution containing different concentrations of EMPs for 7 days. The morphology of samples was observed using scanning electron microscope, and element components and crystal structures of the apatite coatings were analyzed by energy dispersive spectrometer and X-ray diffraction. RESULTS AND METHODS:After double-etching, a pit-like rough surface was observed on the titanium plate. After 7-day mineralization, in the control group, no overt calcium-phosphate deposits were found on the titanium surface;however, in the experimental groups, there were calcium-phosphate deposits, whose quantity and morphology changed with increasing concentrations. Energy dispersive spectrometer showed that the main element components of the mineralized coating included calcium, phosphorus, oxygen and carbon, and the calcium-phosphate ratio ranged from 1.32 to 1.41. The apatite coatings were proved to be carbonate hydroxyapatite by X-ray diffraction. To conclude, EMPs promote apatited deposition on pure titanium surfaces in a concentration-dependent manner.
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<p><b>OBJECTIVE</b>To explore the postburn adhesion properties of polymorphonuclear leukocyte (PMN) onto pulmonary vascular endothelial cells (PVEC) in burn patients with acute lung injury (ALI), so as to determine the role of C5a on PVEC-PMN adhesion.</p><p><b>METHODS</b>Microtubule sucking technique was employed to determine the PVEC-PMN adhesion. The myeloperoxidase (MPO) was also assayed to reflect the magnitude of PVEC-PMN adhesion.</p><p><b>RESULTS</b>The magnitude of PVEC-PMN adhesion increased and the adhesion force increased along with an increase in rh-C5a concentration. Simultaneously, the MPO activity was increased, which could be inhibited by anti-C5aR McAb in a concentration 1:104.</p><p><b>CONCLUSION</b>Both C5a and C5aR participated in PVEC-PMN adhesion, which might be important in the pathogenesis of ALI.</p>
Subject(s)
Humans , Acute Disease , Antibodies, Monoclonal , Pharmacology , Antigens, CD , Allergy and Immunology , Burns , Blood , Cell Adhesion , Cells, Cultured , Complement C5a , Pharmacology , Dose-Response Relationship, Drug , Endothelium, Vascular , Cell Biology , Fetus , Lung , Lung Diseases , Neutrophils , Cell Biology , Peroxidase , Metabolism , Receptor, Anaphylatoxin C5a , Receptors, Complement , Allergy and ImmunologyABSTRACT
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.
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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.
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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.
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Nitrogen mustard encapsulated with liposomes was administered to the rabbits with acute experimental serum sickness(AESS). Then the serum levels of anti-BSA antibodies and circulating; immune complex(CIC), CH50, and WBC count were determined. The ACPase activity of spleen macrophages was measured. And the sections of renal tissues, after HE-stained, were studied for the accumulation of CIC and the pathological changes. It was found that liposome-encapsulated nitrogen mustard can increase the macrophage activity and in turn aggravate the renal damages of AESS rabbits.The results suggest that the renal damages of AESS rabbits can immunopatholo-gically be attributed to the increased activity of macrophages.
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Objective:To explore the relationship between transcription factor AP 1 and NF kappaB and IL 2 decrease in anergic T cells.Methods:Nuclear proteins of activated T cells and anergic T cells were extracted and then the expression of AP 1 and NF kappaB were determinated by gel electrophorotic mobility shift assay.Results:Compared to activated T cells,anergic T cells expressed defective AP 1 transcription factor;there were three forms NF kappaB complex in both activated T cells and agergic T cells,but NF kappaB transcription activity was higher in anergic T cells than that in activated T cells.Conclusion:It has been demonstrated that these alteration of transcription factors have been likely to be responsible for repression of IL 2 in anergic T cells.
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The immunopharmacological effects of anisodamine(654-2)on immune complexnephritis were examined in rabbits with acute experimental serum sickness(AESS).The results showed that activities of renal calmodulin(CaM)and cathepsin D(Cath-D)were significantly high.654-2 could inhibit CaM activity and immune complex-induced lysosomal enzyme release,and lessen immune complex glomerulonephritis at thesame time.Our findings suggest that a marked inhibition of CaM activity by 654-2 mi-ght contribute greatly to the improvement of immune complex glomerulonephritis.
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Objective:To discover some high hydrophilic profiles of the human C5a anaphylatoxin based on relationship between the structure and function of the protein and the protein molecular design principles.Methods:The peptides were synthesized by 431A automatic peptide synthesizer,purified by PHLC and confirmed by caplilliary electrophoresis.Results:The N terminus No.9 30 profile of the C5aR(P22) could interacte with anti C5aR McAb(S5/1,from Serotic Co.),as determined by ELISA.Furthermore,it could be inhibited OD490 values remarkably by 10.0 ?g/L rhC5a(P
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Objective To construct staphylococcal enterotoxin D (SED) mutants expressed in Escherichia coli ( E. coli ). Methods The expected mutants were introduced into the SED DNA by megaprimer PCR method. The PCR products ligated to plasmid pTrcHis B were transformed into E. coli DH5? for IPTG induced expression. The target protein was purified by Ni NTA metal affinity chromatography and analyzed by SDS PAGE and immunoblotting. Results The sequencing results showed that mutant nucleic acids were successfully introduced at the expected sites of SED gene. SDS PAGE and immunoblotting confirmed that the proteins of SED mutants were obtained by Ni NTA metal affinity chromatography. The mutants were named as SEDN23A, SEDN23A/H26R, SEDF45A, SEDL59A, SEDN61A, SEDI92A, and SEDF203A, respectively. Conclusion Several SED mutants are successfully constructed, which lays a foundation for subsequent studies of immune recognition of SED.
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Experimental acute serum sickness was produced in 20 rabbits By a sensitizing injection with bovine serum albumin (BSA) through the auricular vein. Five days after the sensitization, ten of the 20 animals were given a total body irradiation of 300 r from a 60Co sourse. No radiation was given to the other 10 animals which served as controls. Blood samples were taken from the rabbits of both groups before and 2 , 4 , 6 , 8 , 10, 12, 14, and 16 days after antigen injection. After the sera were seperated, the concentrations of the circulating immune complexes were determined with the PEG complement consumption test. It was found that the dynamic curves of the concentrations of the circulating immune complexes of the two groups were essentially similar. This result strongly suggests that total body irradiation of gamma rays given five days after the sensitization of an antigen exerts no influence on the formation of the circulating immune complexes though acute radiation sickness is well established.
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A method, enzyme-linked immunosorbent assay, was introduced for the determination of antigen-specific immune complex (BSA-anti-BSA) in rabbit circulation. The antigen-specific immune complex in the circulation of twelve rabbits were determined by this method. The results showed that this method accords with the regular pattern of immune complex formation more closely than the antigen-nonspecific assay, PEG precipitation method. The procedure of this method is rather simple, its specificity is of high degree, and the amount of serum needed in test is small. This enzyme-linked immunosorbent assay is a better method to determine the circulating specific immune complex in rabbits.
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This experiment takes the apute experimental serum sickness (AESS) in rabbits as an animal model to investigate the mechanism of the regulatory effects of Dexamethasone (DX) . The results show. DX doesn't inhibit the production of anti-BSA antibody but induces the tendency to increase the level of antibody in rabbits with DX administration on early days (EL, EH); immune complexes(BSA - anti-BSA IGg, CIC) in the rabbits of EL and EH are significantly increased comparing with the later days (LE, LH) and positive controls. Non-specific esterase stainings and the pathological changes of kidney sections are markedly lessened though the amount of anti - BSA antibody, circulating immune complex (CIC) and superoxides dismutase activity in the rabbits of LE and L H are the same as the positive control. The outcome of protecting kidneys of AESS rabbits from injury by DX administration . probadly results from the effects of that DX inhibits infiltration of monocytes into the glomeruli. The role of oxygen radicals in AESS needs further investigation.
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Anisodamine (654-2) was administered to rabbits with acute experimental serum sickness (AESS) to study the immunomodulatory effects of 654-2 on AESS. The results suggested that 654-2 may decrease the serum specific antibody and immune complex (IC), inhibit the activity of serum cathepsin D (Cath-D), make the level of complemnts in narrow change, and improved the renal injury.