Antigen‐dependent multistep differentiation of T follicular helper cells and its role in SARS‐CoV‐2 infection and vaccination

T follicular helper (Tfh) cells play an essential role in regulating the GC reaction and, consequently, generation of high-affinity antibodies and memory B cells. Therefore, Tfh are critical for potent humoral immune responses against various pathogens their dysregulation has been linked to autoimmunity cancer. cell differentiation is a multistep process, which cognate interactions with different APC types, costimulatory coinhibitory pathways, as well cytokines involved. However, it still not fully understood how subset activated CD4+ begins express cell-defining chemokine receptor CXCR5 during early stage response, some CXCR5+ pre-Tfh enter B-cell follicles mature further into cells, maintained compartment. In this review, we discuss recent advances on antigen important long-term persistence memory, relevant current understanding COVID-19 pathogenesis development SARS-CoV-2 vaccines.