Biology - Immunology - Basic - Antibodies and antigens - Lock and Key: Antibodies and Antigens

4 steps. Step 1: 'ANTIGENS - Molecules on the surface of pathogens that the immune system recognizes as 'foreign'. Each pathogen has UNIQUE antigens (like a fingerprint). Your own cells have 'self' antigens that your immune system ignores.' Step 2: 'ANTIBODIES - Y-shaped proteins produced by B-lymph