Loss of CD45R (Lp220) represents a post-thymic T cell differentiation event

J Immunol. 1988 Mar 1;140(5):1435-41.


CD45R+ and CDw29+ CD4+ T cells are widely regarded as separate functionally defined T cell lineages. The work described here indicates that they represent maturation stages within the same differentiation pathway. Purified populations of CD4+ or CD8+ T cells, after stimulation with PHA, lose cell surface expression of CD45R (Lp220) and gain an increased surface density of CDw29 (4B4). Clonal analysis demonstrated that individual CD4+ CD45R+ T cells lost CD45R and acquired CDw29 with time in culture. This effect was selective for the high Mr 220-kDa form of the T200 (CD45) complex because the density of CD45, detected by an antibody to common determinants, did not decrease. This strongly indicates that CD45R+ cells are an immature stage in a lineage that culminates in CDw29 expression. To further define the expression of CD45R and CDw29, we analyzed infant thymus cells. Thymocytes include only 4 to 6% CD45R+ cells, but 95% express CDw29 in moderate density. The CD45R+ set appears to include mainly single CD4+ or CD8+, CD3 "bright" medullary cells, although only 15 to 25% of thymocytes with medullary phenotype express CD45R. In vitro culture of thymocytes with Con A and T cell growth factor induces expression of CD45R but these cells differ from the peripheral CD45R+ set by virtue of their co-expression of a high density of CDw29 (4B4) Ag. We postulate that post-thymically CD45R (Lp200) and CDw29 (4B4) comprise a functional assembly on the surface of T cells that changes in composition after stimulation with Ag or mitogen. This may result in enhanced ability of an Ag-experienced T cell to respond effectively to Ag due perhaps to a more efficient signaling complex.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antigens, Differentiation / analysis*
  • Antigens, Differentiation / immunology
  • Antigens, Differentiation, T-Lymphocyte / analysis*
  • Antigens, Differentiation, T-Lymphocyte / immunology
  • Cell Differentiation*
  • Cell Separation
  • Child
  • Clone Cells / analysis
  • Clone Cells / classification
  • Humans
  • Infant
  • Leukocyte Common Antigens
  • Lymphocyte Activation
  • Phenotype
  • Phytohemagglutinins / pharmacology
  • T-Lymphocytes / analysis
  • T-Lymphocytes / cytology*
  • T-Lymphocytes / immunology
  • Thymus Gland / cytology*


  • Antigens, Differentiation
  • Antigens, Differentiation, T-Lymphocyte
  • Phytohemagglutinins
  • Leukocyte Common Antigens