Abstract Humanized rodent models, especially humanization of genetic/genomic components involved in immunity have significantly advanced our understanding of human immune system. Here, we utilized trans-chromosomic (Tc) technology to generate a TC-mAb rat model that stably harbors a mouse artificial chromosome carrying full-length human immunoglobulin (Ig) heavy and kappa light chain genes (IGHK-NAC) in a rat Ig knockout background.