Pathogen-infected host cell recognized by MHC-presented antigen

The process of pathogen-infected host cell recognition via MHC-presented antigen underlies adaptive immunity. Pathogen-derived peptides are processed within host cells and displayed on their surface via MHC class I (for most nucleated cells) or MHC class II (on professional antigen-presenting cells). T cells survey these complexes: cytotoxic CD8+ T cells recognize antigen-MHC class I complexes, responding to intracellular pathogens (like viruses), while helper CD4+ T cells recognize antigen-MHC class II complexes, typically derived from extracellular or phagocytosed pathogens. This recognition triggers targeted immune responses, including killing of infected cells and activation of other immune effectors. This process is crucial in infection control, tumor surveillance, and transplant rejection, but can also underlie autoimmunity when self-antigens are inappropriately presented[2][3][4][5][6][7].

Other names

Antigen recognition by MHC pathwayMHC-mediated pathogen detectionMHC antigen presentation

Immune checkpoint inhibition (drugs that enhance T cell function in the context of antigen presentation)