O fator inibidor da migração de macrófago (MIF) é necessário para a liberação de citocinas durante a infecção pelo vírus sincicial respiratório em macrófagos

Abstract

Respiratory syncytial virus (RSV) is the major cause of infection in children up to five years of age. Reinfection is very common among patients, causing symptoms such as cold or allergy. However, in children, immunosuppressed patients and elderly infection is exacerbated leading to hospitalization and in some case, even death. The number of hospitalizations each year is alarming, even more so because up to now there is still no vaccine for RSV. Tissue damage in the lung caused by RSV leads to an immune response, where infected cells signal activation of signaling pathways, production of reactive oxygen species (ROS), and massive production of inflammatory mediators. Among this production is the macrophage migration inhibitory factor (MIF), which is a pro-inflammatory cytokine, which has been shown to play an important role in the immune response. Knowing this importance, we evaluated MIF expression macrophages from BALB/c mice. The cells were infected with different concentrations of RSV and analyzed by western blot, real-time PCR and Cytometric Bead Array (CBA). After confirmation of MIF expression by the infection, different inhibitors of signaling pathways and ROS were used to evaluate its importance for the expression of MIF. From the results obtained, we showed the dependence of ROS, 5-lipoxygenase (5-LOX), COX, PI3K and partially of P38 MAPK, for MIF expression, besides the need for viral activity. MIF was shown to be important for the release of cytokines such as TNFα, MCP-1 and IL-10. Based on this information MIF may play an important role in the exacerbation of infection, so it was extremely important to explore mechanisms involved in the expression of MIF in relation to RSV.