Of mice and men: HSC transplantation fails to fully regenerate the immune system
Dr. Eliver Ghosen
The current paradigm posits that a single hematopoietic stem cell (HSC) is capable of regenerating all components of the immune system. However, our recent studies in murine HSC transplantation have challenged this broadly accepted paradigm and establishes a novel concept of HSC-independent hematopoiesis. In essence, we showed that long-term (LT)-HSCs, purified from fetal liver and adult bone marrow, selectively fail to regenerate B-1a, a subset of tissue primitive lymphocytes required for protection against Pneumonia, Influenza, and other infectious diseases. Hence, our studies define a lineage of tissue B cells (B-1a) that originates prior to and independent of the HSC and overtly challenge the current paradigm that HSC transplantation regenerates all components of the immune system.