B Cell CD Proteins

B cells, also known as B lymphocytes, are a type of white blood cell of the lymphocyte subtype. They function in the humoral immunity component of the adaptive immune system. In mammals, B cells mature in the bone marrow. B cell activation occurs in the secondary lymphoid organs (SLOs), such as the spleen and lymph nodes. After B cells mature in the bone marrow, they migrate through the blood to SLOs, which receive a constant supply of antigen through circulating lymph. At the SLO, B cell activation begins when the B cell binds to an antigen via its B-cell receptors (BCR). Immature B cells express CD19, CD20, CD34, CD38, and CD45R. Most mature B cells express IgM, CD19, CD20, and CD22. Activated B cells express CD30. Plasma B cells could not express CD19, but could express CD78.