CD27 and infection: In the scRNA-seq dataset, CD21+CD27+ resting Bm cells were the main S+ Bm cell subset at months 6 and 12 post-infection in nonvaccinated individuals, whereas CD21–CD27+CD71+ activated and CD21–CD27–FcRL5+ Bm cells became predominant post-vaccination at month 12 post-infection (Fig. 5a,b and Extended Data Fig. 8g).