褐飞虱抗原检测最佳ELISA条件的建立

应用褐飞虱单克隆抗体3B2和4B8比较了直接、间接和多种抗体夹心ELISA方法.结果表明:当拟环纹豹蛛稀释512倍(含拟环纹豹蛛0.04mg/mL)时,直接和间接ELISA的OD值比阳性对照仍降低5%以上.而当捕食者稀释100倍时,对同种单抗、异种单抗和两种单抗混合夹心ELISA检测OD值的影响均小于5%.在加入100倍豹蛛稀释液时,3种抗体夹心ELISA检测灵敏度均为16.90ng/mL(1/17509头褐飞虱雌成虫),直接和间接ELISA分别为:67.59ng/mL(1/4378头)和135.18ng/mL(1/2189头).建立了4B8稀释1000倍(28.13μg/mL),捕食者匀浆液定容至1mL/头后再稀释100倍,HRP-4B8稀释4000倍(1.04μg/mL)的夹心ELISA用于检测捕食者肠道中的褐飞虱抗原.在此系统下,检测灵敏度为每头拟环纹豹蛛含1.69μg猎物蛋白(1/175头褐飞虱雌成虫),非目标抗原的影响小于5%.

酶联免疫吸附试验方法的比较

应用白背飞虱单克隆抗体比较了３种酶联免疫吸附试验方法。结果表明：间接酶联免疫吸附试验的灵敏度高于直接酶联免疫吸附试验，分别为０．０３１２５μｇ蛋白／ｍｌ（相当于１／２５６头成虫）和０．０６２５μｇ蛋白／ｍｌ（相当于１／１２８头成虫），而双抗夹心酶联免疫吸附试验无法使用。样品中非目标抗原（捕食者）浓度对检测结果有显著的影响，且对直接酶联免疫吸附试验的影响更大。

Disulfide-stabilized single-chain antibody-targeted superantigen: Construction of a prokaryotic expression system and its functional analysis

AIM: To construct the expression vector of B3 (scdsFv)-SEA (D227A) and to identify its binding and cytotoxic ability to B3 antigen positive carcinoma cell lines.METHODS: This fusion protein was produced by a bacterial expression system in this study. It was expressed mainly in the inclusion body. The gene product was solubilized by guanidine hydrochloride, refolded by conventional dilution method, and purified using SP-sepharose cation chromatography.RESULTS: The expression vector B3 (scdsFv)-SEA-PETwas constructed, the expression product existed mainly in the inclusion body, the refolding product retained the binding ability of the single-chain antibody and had cytotoxic effect on HT-29 colon carcinoma cells. The stability assay showed that the resulting protein was stable at 37 ℃.CONCLUSION: This genetically engineered B3 (scdsFv)-SEA fusion protein has bifunction of tumor targeting and tumor cell killing and shows its promises as an effective reagent for tumor-targeted immunotherapy.