B-cells undergo a process of rapid mutagenesis and division which is followed by selection. Somatic hypermutation (SHM) produces many different antibody (Ab) genes that can potentially be useful against a co-evolving pathogen. SHM occurs in structures named germinal centres (GCs). Now, my question, as a student, is: Are SHM and other processes in GC the only factors contributing to the huge variance of antibody genes, or some environmental factors directly influence this variance? (create, destroy or even select some Ab variants) For example, is there any chemical factor that can affect the SHM or selection process with the results of addition, loss or favouring some of the Ab variants produced in GC?