In immunology,<unk>  is the process by which TFH cell-activated B cells produce antibodies with increased<unk>  for antigen during the course of an immune response. With repeated exposures to the same antigen, a host will produce antibodies of successively greater<unk> es. A secondary response can elicit antibodies with several fold greater<unk>  than in a primary response.<unk>  primarily occurs on membrane immunoglobulin of germinal center B cells and as a direct result of somatic hypermutation (SHM) and selection by TFH cells. __TOC__
Affinity maturation
Oocyte selection
Alloantigen recognition
Antigen presentation
MHC restriction
Receptor editing
Protective sequestration
Cross-tolerance