1. Antigens that occur in different forms among individuals of the same species and can trigger an immune response when transferred between those individuals.
Usage: medical/immunology; plural form; singular is isoantigen; also called alloantigens

Examples

• Blood group antigens are examples of isoantigens that differ between individuals.
• The immune system may recognize isoantigens on transplanted organs as foreign.
• Isoantigens on red blood cells determine blood type compatibility for transfusions.
• Researchers study isoantigens to understand transplant rejection mechanisms.
• HLA proteins are important isoantigens in tissue matching for organ donation.