This is an animation describing VDJ Recombination In it, three pre-B cells are attempting to create their B cell receptors. B cell receptors are created by ‘selecting’ one ‘V’ region, one ‘D’ region, and one ‘J’ region, and combining those three choices with a ‘constant’ region. Although only 3 ‘choices’ for each region are shown here, hundreds of different choices are possible in humans. The near endless combination of those different choices, along with a process called junctional diversity, determines the specificity of the B cell receptor (ie. what ‘shape’ it recognizes). In this example, one B cells selection leads to specificity for HIV, while another combination leads to specificity to influenza. Once the receptor has been successfully formed, the B cell is now termed a naive B cell which will be free to roam the body in search of its target antigen.