PDCD1 and infection: The produced immune response could be receptor activation (HLA‐DR, PD‐1, CD69 et cetera), cellular subset differentiation, antibody production (IgM (early infection), IgG and IgG class‐switched isotypes (IgG 1, 2, 3 or 4; later/reinfection), IgA (mucosal surfaces), cytokine response (Th‐1 cytokines; (IL‐1β, IFN‐γ, TNF‐α, Th‐2 cytokines; IL‐4, IL‐10, IL‐5, IL‐13, et cetera, Th‐17 cytokines; IL‐17, IL‐23 et cetera),89 chemokine receptor or chemokine ligands (CXCR3 in response to CXCL9 and CXCL10 stimulation, CXCR5 in response to CXCL13 stimulation et cetera)90, 91, 92, 93 or tolerance (anergy).