Differences in pairing and cluster formation of T cell receptor alpha- and beta-chains in T cell clones and fusion hybridomas.
The questions of T cell receptor (TCR) clustering and preferential pairing of TCR alpha- and beta-chains are discussed controversially. We here describe the rare case of a non-pairing TCR alpha-TCR beta combination detected in the murine T cell hybridoma Hy-E6. Of its two TCR alpha-chains (Valpha3.2, Vbeta17) and one Vbeta16-chain only the Valpha17/Vbeta16 TCR is exposed on the surface, despite intracellular expression of Valpha3.2 protein. The lack of Valpha3.2/Vbeta16 pairing was confirmed by TCR transfections. Surprisingly, however, the parental T cell clone CTL-E6 expressed both alpha-chains on its plasma membrane. Different size distribution of TCR clusters in CTL-E6 versus Hy-E6 and transfectants as determined by Blue-Native gel electrophoresis indicated differences in the supra-molecular TCR assembly as one possible reason for this phenomenon. Our data further reveal that the nominal specificity of CTL-E6 for the fully agonistic trinitrophenyl (TNP) modified peptide M4L-TNP was specifically mediated by the trimeric Valpha3.2/Valpha17/Vbeta16 TCR of CTL-E6. In contrast, the Valpha17/Vbeta16 combination in Hy-E6 only conferred specificity for the cross-reactive partial agonist O4-TNP. Both specificities are H-2Kb-restricted and, hence, appear to be positively selected. The differences in TCR clustering in CTL and hybridoma might indicate differences in the reception and transmission of TCR-signals between these two cell types.
Hellwig
Sven
S
Max-Planck-Institute for Immunobiology, Freiburg, Germany.
Schamel
Wolfgang W A
WW
Pflugfelder
Ulrike
U
Gerlich
Barbara
B
Weltzien
Hans Ulrich
HU
D000595:Amino Acid Sequence; D000818:Animals; D016827:CD8 Antigens / Q000378:metabolism; D002478:Cells, Cultured; D002999:Clone Cells / Q000276:immunology / Q000378:metabolism; D006825:Hybridomas / Q000166:cytology / Q000276:immunology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D010455:Peptides / Q000737:chemistry / Q000494:pharmacology; D010851:Picrates / Q000494:pharmacology; D011485:Protein Binding; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000737:chemistry* / Q000276:immunology* / Q000378:metabolism; D013601:T-Lymphocytes / Q000166:cytology* / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*
D016827:CD8 Antigens; D010455:Peptides; D010851:Picrates; D016693:Receptors, Antigen, T-Cell, alpha-beta; C005858:picric acid