重组AEC／BC02疫苗联合化疗在豚鼠模型中的抗结核效果

Therapeutic evaluation of antibiotics combined with recombinant tuberculosis vaccine AEC/BC02 in a guinea pig model of Mycobacterium tuberculosis infection

目的评价豚鼠感染结核分枝杆菌（Mycobacterium tuberculosis，Mtb）后，抗生素治疗联合重组AEC/BC02疫苗免疫的抗结核效果。方法高剂量结核分枝杆菌皮下攻击豚鼠2周后，将重组ESAT6-CFP10（EC）变态反应原皮试阳性的豚鼠随机分成4组：生理盐水（NS）组、AEC/BC02疫苗组、抗生素组、抗生素＋AEC/BC02疫苗组。抗生素＋AEC/BC02疫苗组接受异烟肼（isoniazid，INH）和利福喷丁（rifapentine，RFT）的联合化疗，1次/周，共3次，给药结束后每只豚鼠开始肌内免疫AEC/BC02疫苗，1只/次，共6次，间隔10 d。AEC/BC02疫苗组仅免疫AEC/BC02疫苗；抗生素组给药INH和RFT。这两组给药剂量和程序同抗生素＋疫苗组。NS组给予生理盐水作为阴性对照。全部豚鼠于攻毒后第14周安乐死解剖，评价肝、脾、肺的脏器综合病变指数，计算脾脏活菌载量（lgCFU），并对肝、脾、肺脏器做组织病理检查。结果NS组、AEC/BC02疫苗组、抗生素组、抗生素＋AEC/BC02疫苗组的脏器评分分别为83±8、77±22、45±28和19±14。其中抗生素＋AEC/BC02疫苗组脏器病变最轻，与抗生素组、AEC/BC02疫苗组和NS组比较，差异均有统计学意义（分别为P〈0.05，P〈0.01，P〈0.01）。抗生素组与AEC/BC02疫苗组和NS组比较，差异均有统计学意义（P均〈0.01）；而AEC/BC02疫苗组与NS组比较，差异无统计学意义。抗生素＋AEC/BC02疫苗组脾活菌数最低，为（2.50±1.26）lgCFU，与NS组的（4.92±0.52）lgCFU、AEC/BC02疫苗组的（4.78±0.84）lgCFU以及抗生素组的（4.39±0.50）lgCFU比较，差异均有统计学意义（P均〈0.01）。抗生素组和AEC/BC02疫苗组的脾脏活菌载量均较高，与NS组比较，差异均无统计学意义。肺病理组织切片：各组肺脏均出现不同程度的以肉芽肿病灶为主的病理变化，病变程度由重到轻为AEC/BC02疫苗组、NS组、抗生素组和抗生素＋AEC/BC02疫苗组。结论INH、RFT和AEC/BC02疫苗联合使用优于抗生素和疫苗的单一治疗方式，能显著减轻动物脏器病变，降低脾肺活菌载量，从而提高对Mtb感染豚鼠的治疗效果。

ObjectiveTo evaluate the therapeutic effect of antibiotics combined with recombinant tuberculosis vaccine AEC/BC02 on Mycobacterium tuberculosis infection in guinea pigs.MethodsTwo weeks after guinea pigs were challenged subcutaneously with a high dose of Mycobacterium tuberculosis, the guinea pigs with the positive skin test responses to the recombinant ESAT6-CFP10 allergen were randomly divided into four groups： normal saline （NS）, AEC/BC02, antibiotics and antibiotics＋ AEC/BC02.In antibiotics＋ AEC/BC02 group, guinea pigs firstly received isoniazid （INH） and rifapentine （RFT） treatment once a week for a total of three times, and then were immunized with a single dose of AEC/BC02 vaccine six times at 10-day intervals.Guinea pigs in AEC/BC02 and antibiotics groups were respectively vaccinated with AEC/BC02 vaccine and given INH and RFT treatment at the same dose and frequency as given to antibiotics＋ AEC/BC02 group.Thirteen weeks after challenge, all guinea pigs were sacrificed for necropsy.ResultsThe gross pathological scores of NS, AEC/BC02, antibiotics and antibiotics＋ AEC/BC02 groups were 83±8, 77±22, 45±28 and 19±14, respectively.Antibiotics＋ AEC/BC02 group had a significantly lower gross pathological score than antibiotics, AEC/BC02 and NS groups （P〈0.05, P〈0.01, P〈0.01, respectively）. Moreover, the gross pathological scores of antibiotics and AEC/BC02 groups were significantly decreased as compared with that of NS group （both P〈0.01）. However, there was no significant difference between AEC/BC02 and NS groups.The spleen bacterial load of antibiotics＋ AEC/BC02 group was （2.50±1.26） lg CFU, which was significantly lower than those of NS [（4.92＋ 0.52） lg CFU], AEC/BC02 [（4.78＋ 0.84） lg CFU] and antibiotics [（4.39＋ 0.50） lg CFU] groups （P〈0.01）. Compared with NS group, antibiotic and AEC/BC02 groups showed no significant difference in spleen bacterial load.Histopathological changes indicated different levels of granulomatous lesions appeared in lung tissues of all groups and the most severe change was observed in AEC/BC02 group, followed by that in NS, antibiotics and antibiotics＋ AEC/BC02 groups.ConclusionINH and RFT treatment in combination with AEC/BC02 vaccine in the treatment of guinea pigs with Mycobacterium tuberculosis infection was superior to either treatment alone as it significantly alleviated organ lesions and lowered the bacterial loads in spleen and lung.