甲型副伤寒结合疫苗人免疫血清破伤风类毒素抗体亲和力的检测与分析

Detection and analysis of human immune serum tetanus toxoid antibody avidity of Salmonella paratyphoid A conjugate vaccine

目的建立甲型副伤寒结合疫苗人免疫血清中破伤风类毒素(tetanus toxoid,TT)抗体亲和力的检测方法,探究甲型副伤寒结合疫苗免疫人体后,免疫系统对载体蛋白质TT的亲和力成熟情况,并分析与免疫后抗体含量增长情况的关系。方法采用间接ELISA检测甲型副伤寒结合疫苗免疫前后血清中TT抗体含量,利用硫氰酸钾(potassium thiocyanate,KSCN)洗脱测定抗体亲和力。检测免疫后抗体含量高增长倍数组(免疫后相比免疫前抗体含量增长>10倍)和低增长倍数组(免疫后相比免疫前抗体含量增长<2倍)血清,计算相对亲和力指数。结果KSCN洗脱对TT与酶标板之间的物理性吸附没有影响(P>0.05)。KSCN的最适洗脱浓度为3.1 mol/L。对于高抗体含量增长倍数组,免疫后相比免疫前抗体亲和力明显成熟,免疫前与免疫后抗体亲和力差异有统计学意义(P=0.0050,P<0.05),对于低抗体含量增长倍数组免疫后抗体亲和力成熟不明显,免疫前与免疫后抗体亲和力差异无统计学意义(P=0.8522,P>0.05)。结论KSCN可用于甲型副伤寒结合疫苗人免疫血清抗体亲和力测定,结果真实、可靠。用单一KSCN浓度洗脱法测定抗体含量差别较大的血清抗体亲和力进行了尝试,免疫前和免疫后血清抗体亲和力都能被良好地测定。对免疫后亲和力明显成熟的高抗体含量增长倍数组,免疫后抗体含量的增长很大程度上依赖于其中高亲和力抗体的增长。

Objective To establish a method for detecting the avidity of tetanus toxoid(TT)antibodies in human immune serum of Salmonella paratyphoid A conjugate vaccine,to investigate the avidity maturation of immune system for the carrier protein TT after immunization with Salmonella paratyphoid A conjugate vaccine,and to analyze the relationship between the antibody avidity maturation and the increase of antibody content postimmunization.Methods An indirect ELISA was used to detect the content of TT antibodies in serum before and after immunization with Salmonella paratyphoid A conjugate vaccine,and potassium thiocyanate(KSCN)elution was used to determine the avidity of antibody.The group with high antibody content growth multiples(the antibody content increased more than 10 fold postimmunization)and the group with low antibody content growth multiples(the antibody content increased less than 2 fold postimmunization)were detected,and the relative avidity index was calculated.Results KSCN elution had no effect on the physical adsorption between TT and microtiter plate(P>0.05).The optimal elution concentration of KSCN was 3.1 mol/L.For the group with high antibody content growth multiples,the antibody avidity was obviously mature compared with that preimmunization,and the difference in antibody avidity between pre-and post-immunization was statistically significant(P=0.0050,P<0.05),for the group with low antibody content growth multiples,the avidity maturation of antibody was not obvious postimmunization,and the difference in antibody avidity between pre-and post-immunization was not statistically significant(P=0.8522,P>0.05).Conclusion KSCN can be used to determine the avidity of antibodies in human immune serum of Salmonella paratyphoid A conjugate vaccine and the result is true and reliable.An attempt was made to determine the avidity of serum antibodies with different antibody content by single KSCN concentration elution method,and the avidity of serum antibodies could be well determined pre-and post-immunization.For the group with high antibody content growth multiples with obviously mature avidity postimmunization,the increase of antibody content postimmunization largely depends on the increase of high avidity antibody.