T cell receptor gene segment usage in a panel of hen-egg white lysozyme specific, I-A(k)-restricted T helper hybridomas

We have studied the relationship between MHC-restricted, Ag-specific recognition and TCR structure in a panel of seven Th-hybridomas specific for the foreign protein Ag, hen egg-white lysozyme, and the I-A(k) class II MHC molecule. The fine specificity of these Th cells had been determined previously by their reactivity to a panel of APC lines bearing mutant I-A(k) molecules and to proteolytic fragments of HEL. TCR gene segment composition was determined by cDNA cloning and DNA sequencing. A heterogeneous, yet repetitive usage of gene segments was observed within the panel. The same V(α) C10-J(α)MD13 rearrangement was used in three of the hybridomas, two with identical Ag and MHC-restriction fine specificities. The prevalent usage of the V(β)14 gene segment and members of J(β)2 cluster was noted. Inasmuch as gene segment usage did not correlate with MHC-restriction or Ag fine specificity alone, these results favor an interactive Ag model of T-cell recognition, in which Ag and MHC are recognized as a bimolecular complex.