Biochemical differences in the alphabeta T cell receptor.CD3 surface complex between CD8+ and CD4+ human mature T lymphocytes

J Biol Chem. 2004 Jun 4;279(23):24485-92. doi: 10.1074/jbc.M311455200. Epub 2004 Apr 1.

Abstract

We have reported the existence of biochemical and conformational differences in the alphabeta T cell receptor (TCR) complex between CD4(+) and CD8(+) CD3gamma-deficient (gamma(-)) mature T cells. In the present study, we have furthered our understanding and extended the observations to primary T lymphocytes from normal (gamma(+)) individuals. Surface TCR.CD3 components from CD4(+) gamma(-) T cells, other than CD3gamma, were detectable and similar in size to CD4(+) gamma(+) controls. Their native TCR.CD3 complex was also similar to CD4(+) gamma(+) controls, except for an alphabeta(deltaepsilon)(2)zeta(2) instead of an alphabetagammaepsilondeltaepsilonzeta(2) stoichiometry. In contrast, the surface TCRalpha, TCRbeta, and CD3delta chains of CD8(+) gamma(-) T cells did not possess their usual sizes. Using confocal immunofluorescence, TCRalpha was hardly detectable in CD8(+) gamma(-) T cells. Blue native gels (BN-PAGE) demonstrated the existence of a heterogeneous population of TCR.CD3 in these cells. Using primary peripheral blood T lymphocytes from normal (gamma(+)) donors, we performed a broad epitopic scan. In contrast to all other TCR.CD3-specific monoclonal antibodies, RW2-8C8 stained CD8(+) better than it did CD4(+) T cells, and the difference was dependent on glycosylation of the TCR.CD3 complex but independent of T cell activation or differentiation. RW2-8C8 staining of CD8(+) T cells was shown to be more dependent on lipid raft integrity than that of CD4(+) T cells. Finally, immunoprecipitation studies on purified primary CD4(+) and CD8(+) T cells revealed the existence of TCR glycosylation differences between the two. Collectively, these results are consistent with the existence of conformational or topological lineage-specific differences in the TCR.CD3 from CD4(+) and CD8(+) wild type T cells. The differences may be relevant for cis interactions during antigen recognition and signal transduction.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Blotting, Western
  • CD3 Complex / chemistry*
  • CD4-Positive T-Lymphocytes / metabolism*
  • CD8-Positive T-Lymphocytes / metabolism*
  • Cell Differentiation
  • Cell Line, Transformed
  • Cell Membrane / metabolism
  • Cells, Cultured
  • Electrophoresis, Polyacrylamide Gel
  • Flow Cytometry
  • Glycosylation
  • Humans
  • Microscopy, Confocal
  • Phenotype
  • Precipitin Tests
  • Protein Conformation
  • Receptors, Antigen, T-Cell, alpha-beta / chemistry*
  • Receptors, Antigen, T-Cell, alpha-beta / metabolism
  • Signal Transduction

Substances

  • CD3 Complex
  • Receptors, Antigen, T-Cell, alpha-beta