Interleukin (IL)-18 increases TLR4 and mannose receptor expression and modulates cytokine production in human monocytes

• Grant number: 14/18692-9
• Support Opportunities: Regular Research Grants - Publications - Scientific article
• Start date: November 01, 2014
• End date: April 30, 2015
• Field of knowledge: Biological Sciences - Immunology - Cellular Immunology
• Principal Investigator: Luciane Alarcão Dias-Melicio
• Grantee: Luciane Alarcão Dias-Melicio
• Host Institution: Faculdade de Medicina (FMB). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil

Abstract

Interleukin-18 is a proinflammatory cytokine belonging to the interleukin-1 family of cytokines. This cytokine exerts many unique biological and immunological effects. To explore the role of IL-18 in inflammatory innate immune responses, we investigated its impact on expression of two toll-like receptors (TLR2 and TLR4) and mannose receptor (MR) by human peripheral blood monocytes, and its effect on TNF-alfa, IL-12, IL-15 and IL-10 production. Monocytes from healthy donors were stimulated or not with IL-18 for 18h, and then the TLR2, TLR4 and MR expression and intracellular TNF-alfa, IL-12 and IL-10 production were assessed by flow cytometry and the levels of TNF-alfa, IL-12, IL-15 and IL-10 in culture supernatants were measured by ELISA. IL-18 treatment was able to increase TLR4 and MR expression by monocytes. The production of TNF-alfa and IL-10 was also increased by cytokine treatment. However, IL-18 was unable to induce neither IL-12 nor IL-15 production by these cells. Taken together, these results show an important role of IL-18 on the initial of inflammatory response by promoting the expression of some pattern recognition receptors (PRRs) that are important during the microbe recognition phase, and by inducing some important cytokines such as TNF-alfa and IL-10. (AU)