Núcleo de Pesquisa em Tuberculose, Departamento de Bioquímica e Imunologia, Universidade de São Paulo, São Paulo, Brazil.
PLoS One. 2010 Jan 15;5(1):e8721. doi: 10.1371/journal.pone.0008721.
We have previously explored a therapeutic strategy for specifically targeting the profibrotic activity of IL-13 during experimental pulmonary fibrosis using a fusion protein comprised of human IL-13 and a mutated form of Pseudomonas aeruginosa exotoxin A (IL13-PE) and observed that the intranasal delivery of IL13-PE reduced bleomycin-induced pulmonary fibrosis through its elimination of IL-13-responsive cells in the lung. The aim of the present study was to determine whether the presence of an immune response to P. aeruginosa and/or its exotoxin A (PE) would diminish the anti-fibrotic properties of IL13-PE.
METHODOLOGY/PRINCIPAL FINDINGS: Fourteen days after P. aeruginosa infection, C57BL/6 mice were injected with bleomycin via the intratracheal route. Other groups of mice received 4 doses of saline or IL13-PE by either intranasal or intraperitoneal application, and were challenged i.t. with bleomycin 28 days later. At day 21 after bleomycin, all mice received either saline vehicle or IL13-PE by the intranasal route and histopatological analyses of whole lung samples were performed at day 28 after bleomycin. Intrapulmonary P. aeruginosa infection promoted a neutralizing IgG2A and IgA antibody response in BALF and serum. Surprisingly, histological analysis showed that a prior P. aeruginosa infection attenuated the development of bleomycin-induced pulmonary fibrosis, which was modestly further attenuated by the intranasal administration of IL13-PE. Although prior intranasal administration of IL13-PE failed to elicit an antibody response, the systemic administration of IL13-PE induced a strong neutralizing antibody response. However, the prior systemic sensitization of mice with IL13-PE did not inhibit the anti-fibrotic effect of IL13-PE in fibrotic mice.
Thus, IL13-PE therapy in pulmonary fibrosis works regardless of the presence of a humoral immune response to Pseudomonas exotoxin A. Interestingly, a prior infection with P. aeruginosa markedly attenuated the pulmonary fibrotic response suggesting that the immune elicitation by this pathogen exerts anti-fibrotic effects.
我们之前探索了一种治疗策略，即通过包含人白细胞介素 13（IL-13）和突变型铜绿假单胞菌外毒素 A（PE）的融合蛋白来专门针对实验性肺纤维化中的 IL-13 的促纤维化活性，观察到鼻内给予 IL13-PE 通过消除肺中对 IL-13 有反应的细胞，减少博莱霉素诱导的肺纤维化。本研究的目的是确定铜绿假单胞菌及其外毒素 A（PE）的存在是否会降低 IL13-PE 的抗纤维化特性。
方法/主要发现：在铜绿假单胞菌感染后 14 天，通过气管内途径向 C57BL/6 小鼠注射博莱霉素。其他组的小鼠通过鼻内或腹腔内应用接受 4 次生理盐水或 IL13-PE 治疗，并在 28 天后用博莱霉素 i.t. 进行挑战。在博莱霉素后 21 天，所有小鼠均通过鼻内途径接受生理盐水或 IL13-PE，在博莱霉素后 28 天进行全肺样本的组织病理学分析。肺内铜绿假单胞菌感染促进 BALF 和血清中中和 IgG2A 和 IgA 抗体反应。令人惊讶的是，组织学分析表明，先前的铜绿假单胞菌感染减弱了博莱霉素诱导的肺纤维化的发展，而鼻内给予 IL13-PE 则适度进一步减弱了这种发展。尽管先前鼻内给予 IL13-PE 未能引起抗体反应，但系统给予 IL13-PE 引起了强烈的中和抗体反应。然而，先前用 IL13-PE 对小鼠进行全身致敏并没有抑制 IL13-PE 在纤维化小鼠中的抗纤维化作用。
因此，IL13-PE 治疗肺纤维化与针对铜绿假单胞菌外毒素 A 的体液免疫反应的存在无关。有趣的是，先前感染铜绿假单胞菌显着减弱了肺纤维化反应，表明该病原体的免疫引发具有抗纤维化作用。
