Invivo Anti-Mouse ICOS Recombinant mAb

ICOS (inducible T-cell costimulator, CD278) is a 55–60 kDa disulfide-linked homodimeric CD28-superfamily receptor expressed mainly on activated CD4⁺ and CD8⁺ T cells, Th17, Tfh and some NK subsets; its surface engagement by the ligand ICOSL (B7-H2/CD275) on antigen-presenting cells delivers a critical secondary signal that amplifies PI3K–AKT–mTOR and MAPK cascades, enhances cytokine transcription (IL-4, IL-10, IL-17, IL-21, IFN-γ), stabilizes Tfh differentiation, germinal-center reactions and class-switch recombination, and promotes memory formation, whereas genetic loss or therapeutic blockade of ICOS attenuates autoimmune pathology in experimental allergic encephalomyelitis, lupus, colitis and graft-versus-host disease yet can dampen antitumor immunity, making the pathway a finely balanced target for both immunosuppressive and immunostimulatory clinical interventions.