To recognise the functions of antibodies and how different regions within the antibody molecule subserve these roles. To realise the essential differences of the primary and the secondary humoral immune response, and the requirement for immunological memory. To appreciate the way in which the immense diversity of antibody specificities is determined. This refers to immunity to infection conferred by proteins termed antibodies. They are unique molecules, derived from the 'immunoglobulin supergene'.
Light chains exist in two classes, lambda and kappa.
Each antibody molecule has either lambda or kappa light chains, not both. Igs are found in serum and in secretions from mucosal surfaces. They are produced and secreted by plasma cells which are found mainly within lymph nodes, and which do not circulate. The links between monomers are made by a J chain. Additionally, IgA molecules receive a secretory component from the epithelial cells into which they pass.