Guimarães Erika S, Martins Jéssica M, Gomes Marco Túlio R, Cerqueira Daiane M, Oliveira Sergio C
Department of Genetics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte 31270-901, Brazil.
Department of Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte 31270-901, Brazil.
Pathogens. 2020 Dec 11;9(12):1040. doi: 10.3390/pathogens9121040.
Interleukin-6 (IL-6) is a pleiotropic cytokine promptly produced in response to infections, which contributes to host defense through the stimulation of acute phase immune responses. is an intracellular bacterium that causes chronic disease in humans and domestic animals and triggers a robust immune response, characterized by the production of inflammatory cytokines. However, the mechanisms of IL-6-related immune responses in the context of infections are not completely understood. In this report, we describe an increased susceptibility of IL-6 knockout (KO) mice in the early phase of infection. Furthermore, we demonstrate that IL-6 is required for interferon (IFN)-γ and tumor necrosis factor (TNF)-α induction by infected splenocytes, indicating a protective role for IL-6 against that parallels with Th1 type of immune response. Additionally, IL-6 KO mice exhibited reduced splenomegaly during the early phase of the infection. Corroborating this result, IL-6 KO mice displayed reduced numbers of macrophages, dendritic cells, and neutrophils in the spleen and reduced myeloperoxidase activity in the liver compared to wild-type infected mice. However, we demonstrate that IL-6 is not involved in intracellular restriction in mouse macrophages. Taken together, our findings demonstrate that IL-6 contributes to host resistance during the early phase of infection in vivo, and suggest that its protective role maybe partially mediated by proinflammatory immune responses and immune cell recruitment.
白细胞介素-6(IL-6)是一种多效性细胞因子,在受到感染后会迅速产生,它通过刺激急性期免疫反应来促进宿主防御。结核分枝杆菌是一种在人类和家畜中引发慢性疾病并触发强烈免疫反应的胞内细菌,其特征是产生炎性细胞因子。然而,在结核分枝杆菌感染的背景下,IL-6相关免疫反应的机制尚未完全明确。在本报告中,我们描述了IL-6基因敲除(KO)小鼠在结核分枝杆菌感染早期阶段易感性增加的情况。此外,我们证明IL-6是被感染的脾细胞诱导产生干扰素(IFN)-γ和肿瘤坏死因子(TNF)-α所必需的,这表明IL-6对结核分枝杆菌具有与Th1型免疫反应相似的保护作用。此外,IL-6 KO小鼠在感染早期脾脏肿大程度减轻。与此结果相符的是,与野生型感染小鼠相比,IL-6 KO小鼠脾脏中的巨噬细胞、树突状细胞和中性粒细胞数量减少,肝脏中的髓过氧化物酶活性降低。然而,我们证明IL-6不参与小鼠巨噬细胞对结核分枝杆菌的细胞内限制。综上所述,我们的研究结果表明IL-6在体内结核分枝杆菌感染早期有助于宿主抵抗,并表明其保护作用可能部分由促炎免疫反应和免疫细胞募集介导。