Laboratório de Bioquímica e Fisiologia de Insetos, Instituto Oswaldo Cruz (IOC/Fiocruz), Rio de Janeiro 21040-360, Brazil.
Institute of Life Science, Swansea University Medical School, Swansea SA2 8PP, UK.
Int J Mol Sci. 2021 Oct 9;22(20):10901. doi: 10.3390/ijms222010901.
Chagas disease is a human infectious disease caused by and can be transmitted by triatomine vectors, such as . One limiting factor for development is the composition of the bacterial gut microbiota in the triatomine. Herein, we analyzed the humoral immune responses of nymphs treated with antibiotics and subsequently recolonized with either or . The treatment with antibiotics reduced the bacterial load in the digestive tract, and the recolonization with each bacterium was successfully detected seven days after treatment. The antibiotic-treated insects, recolonized with , presented reduced antibacterial activity against and phenoloxidase activity in hemolymph, and lower nitric oxide synthase (NOS) and higher defensin C gene (DefC) gene expression in the fat body. These insects also presented a higher expression of DefC, lower prolixicin (Prol), and lower NOS levels in the anterior midgut. However, the antibiotic-treated insects recolonized with had increased antibacterial activity against and lower activity against , higher phenoloxidase activity in hemolymph, and lower NOS expression in the fat body. In the anterior midgut, these insects presented higher , defensin A (DefA) and DefC expression, and lower Prol expression. The immune modulation by these two bacteria was observed not only in the midgut, but also systemically in the fat body, and may be crucial for the development and transmission of the parasites and .
恰加斯病是一种由 引起的人类传染病，可以通过 等三锥虫载体传播。三锥虫肠道细菌菌群的组成是 发展的一个限制因素。在此，我们分析了用抗生素处理的若虫的体液免疫反应，然后用 或 重新定殖。抗生素处理降低了消化道中的细菌负荷，并且在用抗生素处理后七天成功检测到用每种细菌重新定殖。用 重新定殖的抗生素处理过的昆虫对 表现出降低的抗菌活性和血淋巴中的酚氧化酶活性，以及脂肪体中的一氧化氮合酶（NOS）降低和防御素 C 基因（DefC）表达升高。这些昆虫还表现出 DefC 的更高表达，更低的 prolixicin（Prol）和更低的中肠前肠中的 NOS 水平。然而，用 重新定殖的抗生素处理过的昆虫对 表现出更高的抗菌活性和对 的更低的活性，血淋巴中的酚氧化酶活性更高，脂肪体中的 NOS 表达更低。在前肠中，这些昆虫表现出更高的 ，防御素 A（DefA）和 DefC 的表达，以及更低的 Prol 表达。这两种细菌对 的免疫调节不仅在中肠中观察到，而且在脂肪体中也观察到系统，这可能对寄生虫 的发育和传播至关重要。
