1, cellulose is not all antigens, cellulose is a macromolecular polysaccharide composed of glucose. Insoluble in water and general organic solvents. It is the main component of plant cell wall.
2. Antigen refers to substances that produce antibodies, not all of which are protein. Some antigenicity is other macromolecules, such as cellulose, pollen, viruses, fungi and bacteria. Some small molecules can also become antigens, such as penicillin.