Plasmablast levels increased beginning at day 8 post-infection, peaked at day 14 and waned by day 21 (Fig. 1A, Fig. S2A), ranging 1.5–20% of the total CD19+ B cell population among subjects, and expanding on average 8.7–fold (range 2.5–30-fold) from day 0 to peak response (Fig. S2A). The gene discussed is CD19; the disease is infection.