Macrophage Polarization in Inflammatory Diseases

Liu, Yan-Cun; Zou, Xian-Biao; Chai, Yan-Fen; Yao, Yong-Ming

In acute virus infection, macrophage is recruited from the circulation in stimulation of chemokines and serves as a powerful killer of invading pathogens with the secretion of inflammatory mediators, such as TNF-α and inducible nitric oxide synthase [30] . However, the tissue-resident macrophage plays a completely different role in the virus infection. For instance, Kupffer cells (KCs) limit the severity of the virally infected liver through removing apoptotic hepatocytes in a manner dependent on scavenger receptors and thus play a major pathological role in chronic virus associated diseases [31] ; alveolar macrophage is not only the monitor of clearing daily cellular debris, but also the initiator of a strong inflammation response to viral infection [32] . In addition, as the major target of HIV-1 infection, resident macrophage acts as viral reservoir which protects HIV-1 from hostile elements and induces HIV-1 associated neurological damage [33, 34] .