Neonates support lymphopenia-induced proliferation

Immunity. 2003 Jan;18(1):131-40. doi: 10.1016/s1074-7613(02)00508-3.


T cells expand without intentional antigen stimulation when transferred into adult lymphopenic environments. In this study, we show that the physiologic lymphopenic environment existing in neonatal mice also supports CD4 T cell proliferation. Strikingly, naive CD4 T cells that proliferate within neonates acquire the phenotypic and functional characteristics of memory cells. Such proliferation is inhibited by the presence of both memory and naive CD4 T cells, is enhanced by 3-day thymectomy, is independent of IL-7, and requires a class II MHC-TCR interaction and a CD28-mediated signal. CD44(bright) CD4 T cells in neonates have a wide repertoire as judged by the distribution of Vbeta expression. Thus, lymphopenia-induced T cell proliferation is a physiologic process that occurs during the early postnatal period.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Animals, Congenic
  • Animals, Newborn
  • CD4-Positive T-Lymphocytes / immunology
  • CD4-Positive T-Lymphocytes / pathology*
  • CD4-Positive T-Lymphocytes / transplantation
  • Cell Division
  • Hyaluronan Receptors / metabolism
  • Immunologic Memory
  • Lymphocyte Activation
  • Lymphopenia / genetics
  • Lymphopenia / immunology*
  • Lymphopenia / pathology
  • Major Histocompatibility Complex
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Mice, Transgenic
  • Receptors, Antigen, T-Cell / genetics
  • Receptors, Antigen, T-Cell / metabolism
  • Thymectomy


  • Hyaluronan Receptors
  • Receptors, Antigen, T-Cell