mixing of genes into new combinations?

mixing of genes into new combinations?

Genes? Where do the genes come from?

Who mix the genes?

Are the "new combinations" in immune cell?

Context:

Antibody development begins with the mixing of genes into new combinations within the immune cells that make antibodies. Examination of the structure of VRC01 attached to HIV suggested that, from a genetic standpoint, the immune system likely could produce VRC01 precursors readily. The researchers also confirmed that VRC01 does not bind to human cells -- a characteristic that might otherwise lead to its elimination during immune development, a natural mechanism the body employs to prevent autoimmune disease.

http://www.sciencedaily.com/releases/2010/07/100708141531.htm