title: Biochemical differences in the alphabeta T cell receptor.CD3 surface complex between CD8+ and CD4+ human mature T lymphocytes.
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.
authors.affiliation: Inmunología, Facultad de Medicina, Universidad Complutense, 28040 Madrid, Spain.
authors.forename: David A
authors.initials: DA
authors.lastname: Zapata
authors.forename: Wolfgang W A
authors.initials: WW
authors.lastname: Schamel
authors.forename: Pilar S
authors.initials: PS
authors.lastname: Torres
authors.forename: Balbino
authors.initials: B
authors.lastname: Alarcón
authors.forename: Nineth E
authors.initials: NE
authors.lastname: Rossi
authors.forename: María N
authors.initials: MN
authors.lastname: Navarro
authors.forename: María L
authors.initials: ML
authors.lastname: Toribio
authors.forename: José R
authors.initials: JR
authors.lastname: Regueiro
mesh_terms: D015153:Blotting, Western; D017252:CD3 Complex / Q000737:chemistry*; D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism*; D018414:CD8-Positive T-Lymphocytes / Q000378:metabolism*; D002454:Cell Differentiation; D002461:Cell Line, Transformed; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D004591:Electrophoresis, Polyacrylamide Gel; D005434:Flow Cytometry; D006031:Glycosylation; D006801:Humans; D018613:Microscopy, Confocal; D010641:Phenotype; D011233:Precipitin Tests; D011487:Protein Conformation; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000737:chemistry* / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D017252:CD3 Complex; D016693:Receptors, Antigen, T-Cell, alpha-beta