CD41 is a reliable identification and activation marker for murine basophils in the steady state and during helminth and malarial infections.
Bakocevic N., Claser C., Yoshikawa S., Jones LA., Chew S., Goh CC., Malleret B., Larbi A., Ginhoux F., de Lafaille MC., Karasuyama H., Renia L., Ng LG.
Basophils, a rare leukocyte population in peripheral circulation, are conventionally identified as CD45(int) CD49b(+) FcεRI(+) cells. Here, we show that basophils from blood and several organs of naïve wild-type mice express CD41, the α subunit of α(IIb)β₃ integrin. CD41 expression on basophils is upregulated after in vivo IL-3 treatment and during infection with Nippostrongylus brasiliensis (Nb). Moreover, CD41 can be used as a reliable marker for basophils, circumventing technical difficulties associated with FcεRI for basophil identification in a Nb infection model. In vitro anti-IgE cross-linking and IL-3 basophil stimulation showed that CD41 upregulation positively correlates with augmented surface expression of CD200R and increased production of IL-4/IL-13, indicating that CD41 is a basophil activation marker. Furthermore, we found that infection with Plasmodium yoelii 17X (Py17x) induced a profound basophilia and using Mcpt8(DTR) reporter mice as a basophil-specific depletion model, we verified that CD41 can be used as a marker to track basophils in the steady state and during infection. During malarial infection, CD41 expression on basophils is negatively regulated by IFN-γ and positively correlates with increased basophil IL-4 production. In conclusion, we provide evidence that CD41 can be used as both an identification and activation marker for basophils during homeostasis and immune challenge.