Maturation of Lymphocyte Immunophenotypes and Memory T Helper Cell Differentiation During Development in Mice

摘要

The goal of this study was to systematically investigate the ontogeny of lymphoid populationsthroughout postnatal development. In CD-1 mice, peak lymphocyte numbers occurred inblood on postnatal day 10 (dl0) including those for natural killers (NK1.1), B cells (CD19), Thelper (CD3CD4), na?ve T helper (CD4CD62LposCD44low), memory T helper(CD4CD62LnegCD44high), and T cytotoxic (CD3CD8) cells. As percent of total lymphocytes,peaks were achieved by d10 for all T helper subtypes but not B cells which declinedto a nadir. In spleen, lymphocyte numbers increased exponentially after d10. Proportionately,NK and T cells peaked on d10, declined by d20, and increased 2–3-fold by d45. Naive T cellsconstituted the majority of lymphocytes during development while memory cells gained to2.2% (blood) and 12 % (spleen) by d20. C57BL/6 mice had similar profiles except that the Bcell nadir and T cell subset peaks were at d5. Peripheralization of critical numbers of lymphocytesby d10, and importantly, development of a repertoire of memory cells by d20, maydefine immune response capabilities that close the period of immaturity for the neonate.