The NF-[kappa]B1 transcription factor prevents the intrathymic development of CD8 T cells with memory properties

The role of specific members of the NF-I?B family of transcription factors in CD8 T-cell selection and development is largely unknown. Here, we show that mice lacking NF-I?B1 develop a unique population of conventional CD8 single-positive (SP) thymocytes with memory T cell-like properties that populate peripheral immune organs. Development of this memory-like population is not due to PLZF + thymocytes and instead coincides with changes in CD8 T-cell selection. These include a reduction in the efficiency of negative selection and a dependence on MHC class Ia or Ib expressed by haematopoietic cells. These findings indicate that NF-I?B1 regulates multiple events in the thymus that collectively inhibit the excess development of CD8 + thymocytes with memory cell characteristics. A? 2012 European Molecular Biology Organization All Rights Reserved.