Pulmonary inflammatory response to influenza virus infection in pigs is regulated by DAP12 and macrophage M1 and M2 phenotypes

Abstract

We delineated the expression of DAP12 (DNAX-Activating Protein) and its associated receptors, TREM-1, TREM-2 and MDL-1 in pig alveolar monocyte/macrophages (AMM) that have attained M1 or M2 phenotypes. Pig AMM stimulated in vitro with IFN-γ and IL-4 induced the expression of M1 (TNFα and iNOS) and M2 (ARG1 and no MMR) phenotypic markers, respectively. In influenza virus infected pigs at seven days post-infection, in addition to substantial modulations in the M1 and M2 markers expression, DAP12, TREM-1 and MDL-1 were downregulated in AMM. Thus, DAP12 signaling promoted the anti-inflammatory pathway in AMM of influenza virus infected pigs.