Immunology
Antigen
Any molecule that can trigger an immune response, typically by being recognized as foreign. The target that antibodies and T cells recognize.
Biological Context
Antigens are usually proteins or polysaccharides on pathogen surfaces. The immune system learns to distinguish self-antigens from foreign ones. Autoimmune diseases involve attacking self-antigens. Cancer immunotherapy aims to make the immune system recognize tumor antigens.
Business Application
Organizational antigens: the identifying markers of threats—characteristic patterns of fraud, signatures of malicious software, profiles of problematic actors. Systems learn to recognize these patterns.