Cancer Definitions Definitions Antibodies and Antigens Antibodies are proteins composed of two heavy chains and two light chains. Rotating Antibody from Mike Clark's Immunoglobulin Structure Homepage Antibodies recognize epitopes displayed on antigens and facilitate clearance of the antigen.
Antigens are any substance that binds specifically to an antibody or a T-cell receptor.
Macrophages, dendritic cells, and B cells constitute the professional APCs. Nonprofessional APCs, which function in antigen presentation only for short periods, include thymic epithelial cells and vascular endothelial cells. Cell Types B cells are lymphocytes that mature in the bone marrow and express membrane-bound antibody. Following interaction with antigen, B cells differentiate into antibody-secreting plasma cells and memory cells. T cells are lymphocytes that matures in the thymus and express a T-cell receptor, CD3, and CD4 or CD8.