Table 1.
Common surface antigen markers of microglia and other centrally active immune cells
| Marker | Function | Microglial significance |
|---|---|---|
| CD68 | Involved in phagocytosis (Ramprasad et al. 1996) | Localised to monocytes and neutrophils (Saito et al. 1991) |
| CD11b (complement receptor 3) | Regulates leukocyte adhesion and migration to mediate inflammatory response (Meerschaert and Furie 1995) | Expressed in neutrophils, monocytes, natural killer cells, specific lymphocytes (Arnaout 1990) |
| Ionised calcium binding adapter molecule 1 (Iba-1) | Role in membrane ruffling and phagocytosis (Ohsawa et al. 2000) | Expressed centrally by microglia and infiltrating macrophage (Wohleb et al. 2013, Ito et al. 1998) |
| CD45 | Modulates activation and proliferation of inflammatory cell types (Huntington and Tarlinton 2004) | CD45low—quiescent microglia |
| CD45high—peripheral monocytes (Denker et al. 2007) | ||
| IL-1β, TNF-α, IL-6 | Pro-inflammatory cytokines | Released by stimulated neutrophils and monocytes (Konsman et al. 2002) |
| MHC-II | Role in antigen presentation to T cells (St Pierre and Watts 1991) | Expressed centrally by stimulated microglia and macrophage (Aloisi 2001; Xu and Ling 1994) |
| CCL2/MCP-1 | Triggers microglial proliferation and recruits other pro-inflammatory cells (Hinojosa et al. 2011) | Produced by stimulated microglia and expressed in high levels by infiltrating macrophage (Selenica et al. 2013) |
| CX3CR1 (fractalkine receptor) | Role in leukocyte migration and adhesion (Imai et al. 1997) | CCR2low/CX3CR1high—microglia CCR2high/CX3CR1low—monocytes (Mizutani et al. 2012) |