| Antigen | Antibody | |
| Overview | Substance that can induce an immune response | Proteins that recognize and bind to antigens |
| Molecule type | Usually proteins, may also be polysaccharides, lipids or nucleic acids | Proteins |
| Origin | Within the body or externally | Within the body |
| Image |  |
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The Role of Antigens & Antibodies in Vaccinations
Vaccines contain antigens which stimulate the B lymphocytes of the immune system to respond by producing plasma cells which secrete disease specific antibodies (Primary response). Some of the B cells become memory B cells, which will recognise future exposure to the disease. This results in a faster and more intense production of antibodies, which effectively work to eliminate the disease by binding to the antigens (Secondary response).