双歧杆菌脂磷壁酸抗体的制备及其在双歧制品中的检测应用

Preparation of anti-bifidobacteria lipoteichoic acid antibodies and their application in the detection of bifidus products

目的制备双歧杆菌脂磷壁酸抗体并用以检测双歧制品中脂磷壁酸和双歧杆菌活菌的含量。方法提取两歧双歧杆菌脂磷壁酸,加甲基化牛血清白蛋白与佐剂免疫预先已用卡介苗进行多克隆激活的BALB/C小鼠,间接ELISA法检测抗体效价与特异性,用免疫血清经双抗体夹心ELISA法和免疫结合微量培养的方法分别检测酸奶中脂磷壁酸和双歧杆菌活菌量。结果免疫血清最高效价可达1∶1280,与所测其他人体双歧杆菌种属存在较强交叉反应,与非双歧杆菌种属无交叉反应。对于脂磷壁酸和双歧杆菌活菌的含量检测取得良好结果,检测线可达105CFU/ml。结论以双歧杆菌脂磷壁酸制备免疫血清,效价高,属特异性好,可用于双歧食品中脂磷壁酸和双歧杆菌活菌的含量检测。

Objective To prepare polyclonal antibodies against purified lipoteichoic acid （LTA） preparations of bifidobacterium,using them to detect LTA and viable bifidobacterium in bifidus products. Methods Antiserum against LTA preparations of Bifidobacterium bifidum were obtained by injecting LTA/methylated bovin serum albumin complexes with adjuvant into BALB/C mice. All sera, used to detect LTA and viable bifidobacterium in dairy product by double antibody sandwich Enzyme-Linked Immunosorbent Assay （ELISA） and immuno-cuhure method, were analyzed by indirect ELISA procedures to determine specific antibody titer. Results The maximal antibody titer was 1：1280, representing a strong cross-reactivity with other bifidobacteria species of human origin bifidobacterium, while no such reactivity with non- bifidobacterial species was observed. Detection of LTA and viable bifidobacterium were efficiently done, with the detection of at least 10^5CFU/ml. Conclusions Antiserum against ALT gives high titer and is specific and sensitive to the genus Bifidobacterium. It can be used to detect LTA and viable bifidobacterium in bifidus products.