RESUMEN
The transfer of nuclei of fully differentiated cells into enucleated oocytes is a well-recognized method for the generation of embryonic stem (ES) cells. Here, we demonstrate that nuclear transferred ES (NT-ES) cells can be established with high efficiency using innate-like B lymphocytes as donor cells. We established two mouse lines carrying rearranged immunoglobulin heavy and light chains using NT-ES cells containing nuclei from peritoneal cavity B1 cells. Analysis of B1 clone lines revealed that the B1-cell generation critically depends on the interaction between antigen (possibly self-antigen) and surface immunoglobulin, while the B1-cell maintenance requires the peritoneal environment. The B1-cell expansion takes place in spleen, and is held in check by competitor B2 cells. The results indicate that the NT-ES method could replace the transgenic or knock-in mouse approaches currently used to study the biology of cells that undergo somatic rearrangements of their antigen receptor genes.