Generation of hematopoietic humanized mice in the newborn BALB/c-Rag2nullIl2rγnull mouse model: A multivariable optimization approach

Hematopoietic humanized mice generated via transplantation of human hematopoietic stem cells (hHSCs) into immunodeficient mice are a valuable tool for studying development and function of the human immune system. This study was performed to generate a protocol that improves development and quality of humanized mice in the BALB/c-Rag2nullIl2rγnull strain, testing route of injection, in vitro culture and freezing of hHSCs, types of cytokines in the culture, and co-injection of lineage-depleted CD34− cells. Specific hHSC culturing conditions and the addition of support cells were found to increase the frequency, and human hematopoietic chimerism, of humanized mice. The optimized protocol resulted in BALB/c-Rag2nullIl2rγnull humanized mice displaying more consistent human hematopoietic and lymphoid engraftment. Thus, hematopoietic humanized mice generated on a BALB/c immunodeficient background represent a useful model to study the human immune system.