What are the five types of antigens?

The five types of antigens are proteins, polysaccharides, lipids, nucleic acids, and glycoproteins. Proteins and polysaccharides are the most common types, often found on the surfaces of pathogens. Lipids and nucleic acids can also elicit immune responses, though they are less common as antigens. Glycoproteins are important in cell recognition and play a role in immune responses as well.