CD_(40) Ig融合蛋白阻断共刺激信号通路对病毒性心肌炎小鼠的治疗作用

Therapeutic Role of CD_(40) Immunoglobulin Chimera Protein by Blocking T Cell Costimulatory Signals in Mice with Viral Myocarditis

目的探讨CD40Ig融合蛋白(简称CD40Ig)对柯萨奇B3病毒(CVB3)所致病毒性心肌炎(VMC)小鼠死亡率、心肌病理改变和病毒复制的影响。方法106只4～6周龄健康雄性BALB/c小鼠,体质量12～16 g,随机分为CD40Ig组(16只)、病毒组(40只)、IgG组(40只)及正常对照组(10只)。CD40Ig组、病毒组和IgG组小鼠腹腔注射半数组织细胞感染量(TCID50)为10-3L-1的CVB30.15 mL,正常对照组小鼠接种0.15 mL不含病毒的Eagle液。CD40Ig组、IgG组小鼠于接种病毒后6 h、72 h分别注射CD40Ig(0.1 mg.kg-1)及IgG(0.1 mg.kg-1)。接种病毒后第7天处死所有小鼠。在光镜下观察其心肌病理变化,并计算心肌病理组织学积分;采用实时荧光定量PCR检测其心肌组织中CVB3mRNA的表达;采用免疫组织化学法检测其心肌组织中CD40蛋白表达。结果1.与病毒组比较,CD40Ig组小鼠死亡率降低(80.0%vs50.0%,P<0.05)、心肌病理组织学积分下降[(8.88±2.95)分vs(3.42±1.21)分,P<0.05]、心肌CVB3mRNA表达减少(3.48±2.89vs0.91±0.75,P<0.05);2.病毒组和CD40Ig组小鼠心肌组织均有CD40蛋白表达,CD40主要表达于心肌组织中浸润炎性细胞胞膜表面,并且在VMC小鼠的心肌细胞胞膜/胞质中也可见大量CD40蛋白表达。结论CD40Ig可减轻VMC小鼠心肌炎性反应,降低心肌病毒复制及死亡率,其机制可能与CD40Ig阻断CD40和CD40L的相互作用,抑制T淋巴细胞活化有关。

Objective To investigate the effect of CD40 immunoglobulin（CD40Ig） chimera protein on the mortality,viral replication and pathologic changes of myocardinm in mice with viral myocarditis （VMC） induced by coxsaekievirus B3 （ CVB3 ）. Methods One hundred and six healthy male BALB/c mice,4 to 6 weeks old,with weight of 12 to 16 g,were divided into CD40Ig group （n = 16） ,CVB3 group （n =40）, IgG group （n = 40） and normal control group （n = 10） , randomly. Each mouse in CD40Ig group, CVB3 group and IgG group was inoculated intraperitoneally with 0.15 mL CVB3 of 10^-3 · L^-1 50% tissue culture interactive dose（TCID50） and each mouse in normal control group with 0.15 mL Eagle reagent. Each mouse in CD40Ig group and IgG group was inoculated with CD40Ig （0.1 mg· kg^-1 ） and IgG （0.1 mg· kg^-1 ） 6 hours and 72 hours post inoculation, respectively. The surplus mice in each group were sacrificed on day 7 post inoculation. The histopathologic changes were observed by light microscope and the myocardial histopathology scores were calculated. Real - time quantitative - polymerase chain reaction （ RQ - PCR） was used to detect the expression of CVB3 mRNA of myocardium. The expression of CD4o protein in myocardium was determined by immunohistochemistry. Results The mice mortality （ 80% vs 50%, P 〈 0.05 ） , myocardial histopathology score [（8.88±2.95） score vs （3.42±1.21） score,P〈0.05] and myocardial CVB3 mRNA （3.48±2.89vs0.91±0.75 P〈0.05） in CD40Ig group were lower than those in CVB3 group. CD40 expressions were observed in both myocardium of CVB3 group and CD40Ig group. There was strong expression of CD40 on the membrane of infiltrating cells,and on the membrane and cytoplasm of cardiac myocytes in the inflammatory areas of myocardium. Conclusions It is suggested that CD40Ig can relieve myocardial inflammation, decrease myocardial virus replication and mice mortality in CVB3 - induced viral myoearditis. CD40Ig might reduce myocardial injury by blocking the interaction of CD40 with CD40L and inhibiting T lymphocyte activation.