Aavaliação in vitro do perfil fenotípico de cultura primária de macrófagos frente à infecção pela linhagem selvagem T1 e seu mutante linhagemCP13 de Corynebacterium pseudotuberculosis

Abstract

Corynebacterium pseudotuberculosis is a Gram-positive bacterium that belongs to the class Actinobacteria. This bacterium is a facultative intracellular pathogen that causes the disease caseous lymphadenitis (CL) in sheep and goats. During the process of infection by these bacteria are contained cells of the innate immune response, among which the main effectors defensives cells are neutrophils and macrophages. This work has been proposed with the aim of assessing the response of murine bone marrow monocyte-derived macrophages in in vitro infection with the CP13 strain of C. pseudotuberculosis - a knockout mutant for a gene related to the transportation of iron in Corynebacterium diphtheriae that generated good levels of protection against subsequent infections C. pseudotuberculosis - and observe the response profile generated by these cultures. This type of characterization allows the inference of the involvement of innate immune response against infections caused by this bacterium. So far, it was observed that this bacterium is responsible for diminishing the viability of the macrophage cultures in a ratio which depends on the concentration of bacteria inoculated in the cell cultures. The infection of macrophages by C. pseudotuberculosis was responsible for triggering the production of nitric oxide (NO) and inducing the activity of the enzyme arginase I. Also, it showed that the increase in the production of NO and in the activity of the enzyme arginase I are associated with increased expression of the enzyme Inducible Nitric Oxide Synthase (iNOS) and arginase I mRNA. The results also show that strain CP13 does not induce the production of ROS and, compared to the strain T1 - wild-type strain from which the CP13 strain was derived; it induces increased production of the cytokine IL-10 and decreased production of TNF- in macrophages. With these data, it could be infered that the strain CP13 has a similar profile of activation of macrophages compared to the strain T1. However, there was no difference in the profile of cytokines induced in macrophages by infection by strains T1 and CP13, in which the latter induced more IL-10 (cytokine profile associated with an increased susceptibility to microbial infection).