maturation

in immunology
https://doi.org/10.1351/goldbook.13447
Process by which B cells produce antibodies with increased affinity for antigen during the course of an immune response.
Source:
PAC, 2012, 84, 1113. (IUPAC glossary of terms used in immunotoxicology (IUPAC Recommendations 2012)) on page 1211 [Terms] [Paper]