NOD mice were originally procured from Taconic Biosciences, Inc. Anti-insulin VDJH-125 from our original H+L chain 125Tg (25 (link)) mice was cloned to generate a targeting vector, pIVH-SAH-125-VDJH (21 (link)). Founder mice were generated by targeting 129Ola embryonic stem cells and then backcrossed to NOD for at least 10 generations. Southern blot was used to confirm the presence of the targeted allele. All mice were housed under specific pathogen-free conditions, and all studies were approved by the institutional use and animal care committee of Vanderbilt University Medical Center, fully accredited by the AAALAC. Both male and female mice were used to characterize B cell development and function while female mice were employed in disease studies.