CCL2 and infection: The primary role of the chemokines thus produced, such as MCP-1, is to attract resident alveolar macrophages to the site of infection (Deshmane et al., 2009), but in later stages other pro-inflammatory cytokines and chemokines recruit and activate neutrophils, monocytes, and leucocytes from the blood (Craig et al., 2009; Shi and Pamer, 2011; Hickey and Westhorpe, 2013).