Glossary

Adaptive immune system - the arm of the immune system comprising B and T lymphocytes that carry highly diverse receptors for antigens, i.e., membrane bound antibodies and T cell receptors, respectively. During a T cell dependent immune response, the quality of antigen specific antibodies is improved by affinity maturation. Therefore, the quality of the immune response improves and adapts itself to the immunogen. For both B and T lymphocytes, long-lived memory cells with improved immune function develop during an immunization, which is a hallmark of the adaptive immune system.

Affinity - the binding strength of antibodies. The higher the affinity of an antibody, the lower the probability that the antibody binds (crossreacts) to other target antigens.

Affinity maturation - the increase of the binding specificity of antibodies during an immune reaction.

Antigen - an antigen is any molecule or structure that can be bound by antibodies.

B-lymphocytes - the cells of the adaptive immune system producing antibodies.

Chimeric antibodies - antibodies containing variable and constant regions from different species.

Effector functions - the physiologic function of antibodies for activating different mechanisms of the adaptive and innate immune system in the response against pathogens and antigens.

Humanized antibodies - antibodies in which only the parts of antibody variable regions that mediate the contact to antigens have been grafted onto a human antibody framework by means of genetic engineering techniques.

Immunoglobulin - synonymous for antibody.

Monoclonal antibody - a monoclonal antibody is characterized by a defined sequence and structure of its variable regions and can specifically bind to one defined target (or antigen).

Pre-B lymphocyte, pre-B cell - a lymphoid cell committed to B lineage differentiation, which has not yet completed the genetic and phenotypic differentiation program to a B lymphocyte expressing antibodies.

Somatic hypermutation - a still poorly understood process occurring in B lymphocytes during T dependent immune reactions that leads to an extremely high mutation frequency in variable region genes of antibodies.