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Developmental Immunology
Volume 8 (2000), Issue 1, Pages 47-60

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

1lmmunology Center, Department of Pathology, Loma Linda University School of Medicine and Medical Center, 11234 Anderson St. Room 2578, Loma Linda, CA 92354-2870, USA
2Immunology Center, Department of Physiology, Loma Linda University School of Medicine and Medical Center, Loma Linda, CA 92354-2870, USA

Received 7 September 1999; Revised 16 September 1999

Copyright © 2000 Hindawi Publishing Corporation.


The goal of this study was to systematically investigate the ontogeny of lymphoid populations throughout postnatal development. In CD-1 mice, peak lymphocyte numbers occurred in blood on postnatal day 10 (dl0) including those for natural killers (NK1.1), B cells (CD19), T helper (CD3CD4), naïve 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 declined to 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 cells constituted the majority of lymphocytes during development while memory cells gained to 2.2% (blood) and 12 % (spleen) by d20. C57BL/6 mice had similar profiles except that the B cell nadir and T cell subset peaks were at d5. Peripheralization of critical numbers of lymphocytes by d10, and importantly, development of a repertoire of memory cells by d20, may define immune response capabilities that close the period of immaturity for the neonate.