An antigen is a type of molecule that interacts with the constituents of the immune system specifically the antibody. Antibody -Produced to help immune system -Marks foreign cells for destruction -Police the body -Recognizes foreign cells by carbohydrate chains coming off of their cell membrane -Attacks antigens -Change shape to keep attacking the antigen Antigen -Toxin or foreign substance -Attacked by the bodys antibodies. Antigen Presenting Cell Medical Laboratory Science Medical School Studying On the other hand antibodies which are also termed as immunoglobulins comprise of gamma globulin proteins that are contained in the various body fluids and the. . On the other hand an antigen is a foreign substance usually harmful that induces an immune response thereby stimulating the production of antibodies. A protein that binds to the antigen to elicit an immunological response. In simple words Polyclonal antibodies recognize a number of dif