CD69 and infection: To explore this hypothesis in more detail, we examined the expression level of γδT cell activation and replication markers, namely, Cd44, Cd69, Nr4a1, and Mki67. We found that, upon infection, the γδT cells within cluster 2 robustly express Cd44 and Nr4a1, and to a lesser extent Mki67, suggesting local activation and expansion of the γδT cells (Fig. 4D).