Objective To explore the peptides that can mimic the blood type A antigen and evaluate the anti-A antibody detection value of these peptides.Methods The anti-A monoclonal antibodv (NaM87-1F6)was used to panning the phage clones from a phage display 12-mer peptide library.Positive clones were identified by phage ELISA,phage mieropanning methods.Phage DNA Was sequenced and the corresponding peptide sequences were deduced.Agglutination inhibition test WaS performed to assess the ability of phage clones to inhibit the binding between the type A red blood cell and the anti-A antibody. ABO-ELISA based on the selected peptides was compared with classical haemagglutination test jn the detection of senlm anti-A antibody.Results Seven positive clones were chosen after panning,phage ELISA and phage micropanning.Six clones displayed peptide EYWYCGMNRTGC(C5),the other one displayed peptide QIWYERTLPFTF(C17).The phages displaying the selected peptides could specifically inhibit agglutination of type A red blood cells(RBCs)by anti-A antibodies.In the ABO-ELISA based on C5 and C17,the receiver operating characteristic(ROC)Curve showed that area under curve(AUC)were 0.889 (P=0.000),0.75l(P=0.000)respectively.The Spearman correlation Coeffieient between the ABO-EliSA value and the antibody titer derived from haemagglutination assay were 0.743(P<0.01),0.664(P<0.01)respectively.As for C5,0.300 was the best cut-off for ABO-ELISA with 82.2% sensitivity and 83.3% specificity.As for C17,the sensitivity and specificity of ABO-ELISA was 68.9% and 63.3% respectively when the cut-off value was 0.250.Conclusions The peptides EYWYCGMNRTGC and QIWYERTLPFTF can mimic the blood type A antigenic epitope.ABO-ELISA based on these peptides has the potential for the detection of anti-A antibody.

OBJECTIVETo investigate the cytotoxic effect of γδ T cells from osteosarcoma patients against interferon-γ (IFN-γ)-treated osteosarcoma cells in vitro.

METHODSHuman γδ T cells were amplified by zoledronate from peripheral blood cells of osteosarcoma patients. The expression of Fas on the osteosarcoma cells were measured by flow cytometry and quantitative real-time PCR analysis before and after IFN-γ treatment. The cytotoxicity of γδ T cells against osteosarcoma cells was evaluated with LDH assay.

RESULTSIFN-γ significantly enhanced the susceptibility of the osteosarcoma cell lines HOS and U2OS to the cytotoxicity of γDelta; T cells from osteosarcoma patients (P<0.01). IFN-γ obviously up-regulated the expression of Fas in HOS and U2OS cells (P<0.01). Anti-FasL mAb failed to inhibit the cytotoxicity of γδ T cells in untreated osteosarcoma targets (P>0.05), but significantly impaired γδ T cell cytotoxicity in IFN-γ pre-treated osteosarcoma targets (P<0.01).

CONCLUSIONIFN-γ can enhance the cytotoxic effect of human γδ T cells from osteosarcoma patients against osteosarcoma cells in vitro.

Bone Neoplasms ; metabolism ; Cell Line, Tumor ; Cytotoxicity, Immunologic ; Humans ; Interferon-gamma ; pharmacology ; Osteosarcoma ; immunology ; metabolism ; Receptors, Antigen, T-Cell, gamma-delta ; immunology ; T-Lymphocytes, Cytotoxic ; cytology ; drug effects ; immunology ; fas Receptor ; metabolism