Table 1.
Markers to classify M1 and M2 microglia commonly used in studies of TBI
| Study | Microglial polarization | Other microglial activation markers used | |
|---|---|---|---|
| M1 | M2 | ||
| Jin et al. (2012) | CD86 | CD206 | Iba‐1, CD11b+ CD45low‐expressing cells characterized as microglia |
| Wang et al. (2013) | CD32, CD16, iNOS, CD11b, CD86 | CD206, IL‐10, Ym1/2, TGF‐β, Arg‐1, CCL22 | Iba‐1 |
| Kumar et al. (2013) | IL‐1β, TNF‐α, CD86, iNOS, CCL2, CCL3 (classical activation) | Arg‐1, Ym1, Mrc, Fizz‐1 (alternative activation; M2a) and IL‐4rα, SOCS3, TGF‐β (acquired deactivation; M2c) | Iba‐1, CD11b, ED1, MHC II |
| Cao et al. (2012) | TNF‐α, CD45 (classical activation) | Arg‐1 (alternative activation), TGF‐βΙ, TGF‐βRII (acquired deactivation) | Iba‐1, MHC I, MHC II, TSPO |
| Bachstetter et al. (2013) | IL‐1β, IL‐6, TNF‐α, CCL2, CCL3 (classical activation) | Arg‐1, Ym1 (alternative activation) | Iba‐1, CD68, CD45, MHC II |
| Dohi et al. (2010) | iNOS, NO, TNF‐α (classical activation) | Arg‐1, Ym1 (alternative activation) | CD11B |
Some studies use the nomenclature M2a and M2c (‘alternative activation’ and ‘acquired deactivation’) to describe M2 microglia and ‘classical activation’ for M1 microglia.
Arg‐1, arginase‐1; iNOS, inducible NOS.