妊娠对小鼠旋毛虫感染免疫应答的影响

目的 研究妊娠对小鼠旋毛虫感染免疫应答的影响。 方法 6只孕鼠分别经口感染300条旋毛虫肌幼虫,ELISA检测感染后不同时间血清抗体水平。感染后6周剖杀,消化全身肌肉计算每克肌肉虫荷（lpg）。测定孕鼠感染后1～4周血清介导的抗体依赖细胞介导的细胞毒性作用（ADCC）对成囊前期幼虫（PEL）的杀伤作用。观察孕鼠感染旋毛虫后第6、8和12天的肠道虫荷及雌虫体外生殖力指数。对6只处女鼠肌肉注射孕酮,观察其感染旋毛虫后6周的血清抗体水平与肌肉虫荷。 结果 孕鼠感染旋毛虫后2周的血清抗体水平（A492=0.113）显著高于未孕鼠（A492=0.078）（F=21.390,P＜0.05）。孕鼠感染后6周的每克肌肉虫荷（1 251±450）明显低于未孕鼠（2 310±1 123）（t=2.419,P＜0.05）。孕鼠感染后2周血清介导的ADCC导致成囊前期幼虫的死亡率（42.6%）显著高于未孕鼠（26.9%）（F=1.195,P＜0.05）。孕鼠感染后第6、8和12天的肠道虫荷与未孕鼠相比差异均无统计学意义（Z6=-1.185,Z8=-0.149,Z12=-0.0289,P＞0.05）,感染后第6和8天孕鼠与未孕鼠的雌虫生殖力指数间的差异亦无统计学意义（Z6=-0.149,Z8=-1.043,P＞0.05）。孕酮注射处女鼠感染旋毛虫后6周的血清抗体水平（A492=0.299）显著高于对照组（A492=0.191）（t=2.955,P＜0.05）,但其每克肌肉虫荷（1 457±551）与对照组（1 235±439）相比差异无统计学意义（t=0.726,P＞0.05）。 结论 妊娠在小鼠抗旋毛虫感染的免疫应答中具有协同作用,其机制可能与孕鼠感染旋毛虫后早期血清抗体水平升高及其介导的ADCC对成囊前期幼虫的杀伤作用增强等有关。

Effect of Pregnancy on the Immune Response against Trichinella spiralis Infection in Mice

Objective To study the effect of pregnancy on the immune response against Trichinella spiralis infection in mice. Methods Six pregnant mice were orally infected each with 300 muscle larvae of T. spiralis,and the serum anti-Trichinella antibodies at different time after infection were detected by ELISA. The mice were sacrificed 6 weeks after infection and the carcass was digested to observe the muscle larval burden（larvae per gram,lpg）. The ability of sera from infected pregnant mice to mediate the death of pre-encapsulated larvae（PEL）were assayed in an antibody-dependent cell-mediated cytotoxicity（ADCC）. On 6th,8th and 12th day after infection,the infected pregnant mice were sacrificed to examine the intestinal worm burden and the fecundity index of female worms in vitro. Six virgin mice injected with progesterone were infected with T. spiralis,the serum antibodies and muscle larval burden were detected 6 weeks after infection. Results The absorbance value of sera from pregnant mice（0.113）were significantly higher than that from virgin mice （0.078） at 2 weeks after infection （F=21.390,P＜0.05）. The muscle larval burden in pregnant mice（1 251±450 lpg）was significantly lower than that of virgin mice（2 310±1 123 lpg）6 weeks after infection（t=2.419,P＜0.05）. The ability of sera to mediate the death of pre-encapsulate larvae in ADCC was significantly higher in pregnant mice（42.6%）than in virgin mice（26.9%）at 2 weeks after infection（F=1.195,P＜0.05）. The difference of intestinal worm burdens on 6th,8th and 12th day after infection have no statistical significance between pregnant and virgin mice （Z6=-1.185,Z8=-0.149,Z12=-0.298,P＞0.05）,so did the difference of fecundity index of female worms in vitro on 6th and 8th day after infection between the two groups（Z6=-0.149,Z8=-1.043,P＞0.05）. Serum absorbance value of progesterone injected virgin mice（0.299）was significantly higher than that of no-injected virgin mice（0.191）（t=2.955,P＜0.05）,but the difference of muscle larval burden between the injected （1 457±551） and no-injected virgin mice （1 235±439） showed no statistical significance（t=0.726,P＞0.05）. Conclusion Pregnancy has a synergetic effect on immune response of mice against T. spiralis infection,which may be related with the increased level of serum anti-Trichinella antibody and enhanced ability of sera in mediating the death of pre-encapsulated larvae in ADCC.