Fig. 1

Humoral immune memory responses. A Humoral immune responses to a primary antigen exposure are depicted. Viral infection or vaccination induces B_mem and plasma cells through germinal center reaction, conferring immunological memory. B Memory responses to antigen re-exposure are described. Pre-existing antibodies secreted from long-lived plasma cells rapidly eliminate the viruses, whereas B_mem cells function as a backup reservoir for plasma cells. The figure was created with BioRender.com