Vaccines primarily work by:
Vaccines function primarily by inducing immunological memory mimicking natural infection without causing severe pathology. Upon antigen administration intramuscularly or mucosally, local dendritic cells and macrophages sense danger signals via pattern recognition receptors TLR, NLR, STING. Activated dendritic cells pick up antigen, mature upregulating CCR7, migrate to draining lymph node T cell zone presenting peptides on MHC class II to naive CD4 T cells and via cross presentation on MHC I to CD8 cells. T follicular helper cells provide IL-21 and CD40L signals to B cells in germinal centers d
Ref: Pollard Bijker Nat Rev Immunol 2021 Vaccine memory; Janeway Immunobiology 9th ed Ch 12.
