Describe how phagocytosis of a virus leads to presentation of its antigens.

Describe how presentation of a virus antigen leads to the secretion of an antibody against this virus antigen.

Collagen is a protein produced by cells in joints, such as the knee.

Rheumatoid arthritis (RA) is an auto-immune disease. In an auto-immune disease, a person's immune system attacks their own cells. RA causes pain, swelling and stiffness in the joints.

Scientists have found a virus that produces a protein very similar to human collagen.

Suggest how the immune response to this viral protein can result in the development of RA.