大肠埃希菌表达的恶性疟原虫裂殖子表面蛋白MSP1-42的免疫原性

目的纯化大肠埃希菌Rosettagami（DE3）表达的可溶性裂殖子表面蛋白1C末端蛋白（MSP1-42，3D7株），检测其体外抑制恶性疟原虫生长的效果。方法利用大肠埃希菌Rosettagami（DE3）为宿主菌诱导表达MSP1-42，用带组氨酸标签的镍柱纯化可溶性的MSP1-42。6只新西兰白兔随机分为免疫组和对照组，每组3只。用MSP142与弗氏佐剂乳化后，皮下注射，抗原免疫剂量每次为200“g／只，共免疫4次，每次间隔2周。佐剂对照组以PBS代替抗原同法免疫。免疫前及末次免疫2周后取血，用酶联免疫吸附试验和间接荧光抗体试验检测血清中特异性抗体及其与天然抗原的反应，用含10％和20％免疫血清的培养基体外培养恶性疟原虫（海南分离株，Fcc1／HN），检测免疫血清体外抑制恶性疟原虫生长的效果。结果经镍柱纯化后获得纯度为95％以上的MSP1-42蛋白；免疫组个体在第4次免疫后血清特异性抗体的滴度依次为1：640000、1：640000、1：160000，间接荧光抗体试验检测表明MSP1-42免疫兔血清与恶性疟原虫表面蛋白有阳性反应；免疫血清能抑制恶性疟原虫在体外生长，在10％浓度时，3只免疫兔血清的抑制率依次为（51．94-24．2）％、（29．4±8．6）％和（86．7±7．4）％，在20％浓度时，抑制率分别为（93．3±7．5）％、（65．3±10．6）％和（96．4±1．0）％。结论大肠埃希菌Rosettagami（DE3）表达的MSP142蛋白免疫血清能识别恶性疟原虫天然抗原，体外培养能抑制恶性疟原虫的生长。

Immunogenieity analysis of 42 kDa C-terminal region of merozoite surface protein 1 of Plasmodiun falciparum expressed in Rosetta gami

Objective To purify soluble recombinant MSP1-42 protein of Plasmodiun falciparum （3D7 strain） expressed in Rosetta gami and evaluate its immunogenicity. Methods Soluble recombinant MSP1-42 protein expressed in Rosetta gami （DE3） was purified by Ni-NTA affinity chromatography, Three New Zealand white rabbits were immunized subcutaneously with 200 txg of purified MSP1-42 antigen formulated in Freund＇s adjuvant, while three control rabbits received only adjuvant emulsified with PBS. All the rabbits received four immunizations with 2-week intervals. Sera samples were collected at pre-immunization and two weeks after the final immunization, and were analyzed for specific antibodies by ELISA and reacted with natural P. falciparum （Fcc1/HN） proteins by IFA. The inhibition of parasite growth in vitro was evaluated on heterologous parasite line （P. falciparum, Fcc1/HN） with 10% and 20% anti-MSP1-42 rabbit sera,respectively. Results The MSPI-42 antigen purified was homogeneous. High antibody responses were detected in the three immunized rabbits and the antibody titers were 1： 640 000,1 ： 640 000 and 1：160 000 ,respectively. The anti-MSP1-42 rabbit sera prepared could recognize the natural proteins of P. falciparum （Fcc1/ HN） and the inhibition of parasite growth in vitro of the three immunized rabbits sera at the concentration of 10% and 20% were （51.9 ±24.2）%, （29.4 ±8.6）%, （86.7 ±7.4）% and （93.3 ±7.5）%, （65.3 ±10.6）%, （96.4± 1.0）%, respectively.
Conclusions The MSP1-42 protein expressed in Rosetta gami is highly immunogenie and the anti-MSP1-42 rabbit sera prepared can interact with natural proteins of P. falciparum parasites and inhibit parasite growth in vitro.