Starting at the end

From the time when I entered immunology - in January 1965 at the Salk Institute for Biological Studies in La Jolla, California in the laboratories of Edwin (Ed) Lennox and Melvin (Mel) Cohn - my love has always been B lymphocytes and antibodies. I began my studies at the end of the developmental pathway of these B cells, with plasma cells. After more than 40 years in immunology, I have moved "backwards" over mature B cells, immature B cells, precursor B cells and lymphocyte progenitors to pluripotent hematopoietic stem cells. Initially it was an intellectual exercise to trace the unknown progenitor of known B-lineage cells; now it has become an experimental approach - to de- and re-differentiate B-lineage cells to earlier differentiation stages and to other lineages of hematopoietic cells.