Biochemical evidence of the physical association of the majority of CD3 delta chains with the accessory/co-receptor molecules CD4 and CD8 on nonactivated T lymphocytes.
The association of components of the CD3 complex with the accessory molecules CD4 and CD8 was studied by immunoprecipitation experiments followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis. Enhanced surface iodination was achieved by a water-soluble derivative of the Bolton-Hunter reagent. Using freshly isolated nonactivated splenic T cells, we find that antibodies to CD4 and to CD8 strongly co-precipitate a 28-30-kDa band identical in mobility to the delta chain of the CD3 complex. Components corresponding in mobility to the epsilon and gamma chains of the CD3 complex are also co-precipitated but to a much lesser extent. The identity of the co-precipitated 28-30-kDa material with the CD3 delta chain was ascertained by two-dimensional nonreducing/reducing SDS-PAGE, by two-dimensional non-equilibrium pH gradient electrophoresis/SDS-PAGE and by one-dimensional peptide mapping with three different proteases. The co-precipitated 28-30-kDa material was identical to the CD3 delta chain by all these criteria. Quantitative analyses by densitometric gel tracing revealed that the amounts of CD3 delta co-precipitated with anti-CD4 and anti-CD8 add up to those in anti-V beta precipitates and to an average of 90% of those in anti-CD3 epsilon precipitates. We conclude that the majority of CD3 delta chains are associated with the accessory/co-receptor molecules CD4 or CD8 on resting T cells, and that this association is independent of antigen-specific recognition by the T cell receptor.
Suzuki
S
S
Max-Planck-Institut für Immunbiologie, Freiburg.
Kupsch
J
J
Eichmann
K
K
Saizawa
M K
MK
D000818:Animals; D017252:CD3 Complex / Q000032:analysis*; D015704:CD4 Antigens / Q000032:analysis*; D016827:CD8 Antigens / Q000032:analysis*; D004591:Electrophoresis, Polyacrylamide Gel; D008213:Lymphocyte Activation; D051379:Mice; D011233:Precipitin Tests; D013601:T-Lymphocytes / Q000276:immunology*
D017252:CD3 Complex; D015704:CD4 Antigens; D016827:CD8 Antigens