Rituxan® (rituximab) isi a good example of a monoclonal antibody that can activate the immune system to attack a cancer cell. It binds to a surface protein, called CD20, located on mature B lymphocytes (B cells). Once bound, the antibody activates the body's immune system, which then attacks the cancer cells. Rituxan® (rituximab) may also make cells more susceptible to chemotherapy, promoting more cell death by apoptosis.
Because CD20 is on all B cells, Rituxan® (rituximab) kills normal as well as cancer cells. However, patients can regenerate normal B cells from their own or transplanted blood stem cells.