藻酸盐在铜绿假单胞菌肺部感染中的致病作用及与细胞因子的关系

Pathogenic Role of Alginate in Pulmonary Pseudomonas aeruginosa Infection and Its Relationship with Cytokines

目的 研究铜绿假单胞菌藻酸盐的致病作用及其与细胞因子的关系。方法 用柱层析法从粘液型铜绿假单胞菌株PT 12 5 2提纯藻酸盐并用它来免疫小鼠 ;用酶联免疫吸附法 (ELISA)测定小鼠血清中的抗藻酸盐抗体滴度 ;免疫后的小鼠被雾化吸入PT 12 5 2菌株造成肺部感染 ;取小鼠支气管肺泡灌洗液 (BALF)作细胞计数和分类 ;用ELISA法测定小鼠血清中的白介素 (IL) 2、4、10、12及肿瘤坏死因子 α(TNF α)和干扰素 γ(IFN γ)的浓度。结果 免疫组小鼠在吸入铜绿假单胞菌后的第 3、7天 ,血清中的抗藻酸盐抗体较对照组有显著增高 ,BALF中细胞总数在第 1、3、7天 ,淋巴细胞数在第 1、3天 ,中性粒细胞在第 3、7天较对照组有显著升高 ;病理切片显示免疫组小鼠气道周围有较显著的炎症反应 ;免疫组小鼠血清IL 12浓度在第 7天较对照组显著升高。结论 被藻酸盐免疫过的小鼠在吸入铜绿假单胞菌后 ,铜绿假单胞菌藻酸盐作为一种抗原物质 ,介导了抗原抗体反应 ,从而引起了较强的气道局部炎症反应 ,这种反应可能与IL 12有关。

OBJECTIVE The pathogenic role of alginate from Pseudomonas aeruginosa and its relationship with cytokines were studied. METHODS Alginate from mucoid strain PT-1252 was purified by anion-exchange chromatograph. Mice were immunized with alginate and then inhaled with the same strain. Anti-alginate antibody titer was detected with enzyme linked immunosorbent assay (ELISA) method. The cell count and differential count in bronchoalveolar lavage fluid (BALF) were detected. Concentrations of interleukin (IL)-2, IL-4, IL-10, IL-12, tumor necrosis factor(TNF)-α and interferon(INF)-γ in sera were measured with ELISA methods. RESULTS The sera anti-alginate IgG antibody titer of immunized mice was increased significantly at the 3rd and 7th days after inhalation. The total cell count ( at the 1st, 3rd and 7th days) and the differential count of lymphocyte in BALF ( at the 1st and 3rd days) of immunized mice were significantly higher than those of control mice. Neutrophils in BALF were increased significantly at the 3rd and 7th days. The IL-12 concentration of immunized mice was significantly higher in immunized mice at the 7th day after inhalation. CONCLUSIONS We think that when alginate-preimmunized mice are inhaled with mucoid strains of P.aeruginosa, the alginate and anti-alginate antibody reaction is occurred on the surface of small airway surface, IL-12 level is elevated by a unknown mechanism. It could cause inflammatory reaction and lung tissue injury.