不同剂量伤寒Vi多糖蛋白结合疫苗在小鼠体内诱导的抗体水平分析

Analysis of antibody level in mouse model induced by different immunization doses of typhoid Vi conjugate vaccine

目的研究伤寒Vi多糖蛋白结合疫苗免疫效果及不同剂量伤寒Vi多糖蛋白结合疫苗在小鼠体内诱导的抗体水平,以确定合适的免疫剂量。方法将150只清洁级NIH雌性小鼠随机分为5组,分别为A组(0.625μg结合疫苗组)、B组(1.250μg结合疫苗组)、C组(2.500μg结合疫苗组)、D组(2.500μg多糖组)及阴性组(10mmol/L PBS),每组30只;另领取10只为空白对照(不接种)。A、B、C、D组及阴性组小鼠经腹股沟皮下注射,剂量0.1 m L/只,每隔2周免疫1次,共免疫3次,每次免疫后第7天采血。采用ELISA检测小鼠血清抗体效价,同时对不同剂量伤寒Vi多糖蛋白结合疫苗在小鼠体内诱导的抗体效价进行分析比较。结果与D组相比,A、B、C三组诱导的抗体水平与之均有统计学意义(P<0.05);A组与B组、A组与C组之间的抗体水平也具有统计学意义(P<0.05),而B组与C组之间的抗体水平无统计学意义(P>0.05)。说明与多糖疫苗相比,伤寒Vi多糖蛋白结合疫苗能够诱导更高的抗体水平,且具有明显的剂次加强效应。同时证明1.250μg的伤寒Vi多糖蛋白结合疫苗可诱导与2.500μg伤寒Vi多糖蛋白结合疫苗相同的抗体水平。结论伤寒Vi多糖蛋白结合疫苗的两种免疫剂量在小鼠体内可诱导相同的抗体水平,在选择接种剂量时,可致免疫应答的无统计学意义的低剂量可能是较为经济和安全的选择。

Objective To study immunological potency of typhoid Vi conjugate vaccine and analyze antibody level in the mouse model induced by different immunization doses of typhoid Vi conjugate vaccine, on which a suitable immunization dose could be set up.Methods A total of 150 NIH female mice （ in clean level） were randomly devided into five groups including--group A （0.625μg conjugate vaccine）, group B （1.250μg conjugate vaccine）, group C （2.500μg conjugate vaccine）, group D （2.500 μg typhoid Vi polysaccharide） and negative group （10 mmol/L PBS）, 30 mice for each.The other 10 mice were used for blank control （ non-immunization） .Mice were immunized by a subcutaneous injection at groin, with a dose of 0.1mL/per mouse, for three times at intervals of each two weeks, serum were collected after seven days on each immunization.The mouse serum antibody potency was determined by ELISA, based on antibody ELISA unit, antibody titer and antibody positive rate to analyze and compare antibody potency in mouse model induced by different immunization doses of typhoid Vi conjugate vaccine.Results Compared to group D, the antibody level of group A, group B and group C showed a statistical differences （ P〈0.05 ）; The statistical differences＆amp;nbsp;were observed in antibody level in group A to group B and group A to group C（P〈0.05）, but there were no statistical difference in antibody level in group B to group C.Compared to polysaccharide vaccine, typhoid Vi conjugate vaccine could induce a more higher antibody level and a dose enhancing effect.At the same time it proved that 1.250μg typhoid Vi con-jugate vaccine could induce a same antibody level as that by 2.500μg typhoid Vi conjugate vaccine did.Conclusion The same antibody level could be induced by typhoid Vi conjugate vaccine with the two different doses, It is to select a suitable immunization dose by using of a low dose without a statistical difference in response that may be a more economic and safe selection.