Preferential V beta gene usage and lack of junctional sequence conservation among human T cell receptors specific for a tetanus toxin-derived peptide: evidence for a dominant role of a germline-encoded V region in antigen/major histocompatibility complex recognition.
To investigate the structural and genetic basis of the T cell response to defined peptide/major histocompatibility (MHC) class II complexes in humans, we established a large panel of T cell clones (61) from donors of different HLA-DR haplotypes and reactive with a tetanus toxin-derived peptide (tt830-844) recognized in association with most DR molecules (universal peptide). By using a bacterial enterotoxin-based proliferation assay and cDNA sequencing, we found preferential use of a particular V beta region gene segment, V beta 2.1, in three of the individuals studied (64%, n = 58), irrespective of whether the peptide was presented by the DR6wcI, DR4w4, or DRw11.1 and DRw11.2 alleles, demonstrating that shared MHC class II antigens are not required for shared V beta gene use by T cell receptors (TCRs) specific for this peptide. V alpha gene use was more heterogeneous, with at least seven different V alpha segments derived from five distinct families encoding alpha chains able to pair with V beta 2.1 chains to form a tt830-844/DR-specific binding site. Several cases were found of clones restricted to different DR alleles that expressed identical V beta and (or very closely related) V alpha gene segments and that differed only in their junctional sequences. Thus, changes in the putative complementary determining region 3 (CDR3) of the TCR may, in certain cases, alter MHC specificity and maintain peptide reactivity. Finally, in contrast to what has been observed in other defined peptide/MHC systems, a striking heterogeneity was found in the junctional regions of both alpha and beta chains, even for TCRs with identical V alpha and/or V beta gene segments and the same restriction. Among 14 anti-tt830-844 clones using the V beta 2.1 gene segment, 14 unique V beta-D-J beta junctions were found, with no evident conservation in length and/or amino acid composition. One interpretation for this apparent lack of coselection of specific junctional sequences in the context of a common V element, V beta 2.1, is that this V region plays a dominant role in the recognition of the tt830-844/DR complex.
Laboratory of Molecular Immunology, Pasteur Institute, Paris, France.
B
B
Boitel
M
M
Ermonval
P
P
Panina-Bordignon
R A
RA
Mariuzza
A
A
Lanzavecchia
O
O
Acuto
D000595:Amino Acid Sequence; D001483:Base Sequence; D002999:Clone Cells; D000939:Epitopes; D005803:Genes, Immunoglobulin; D006684:HLA-DR Antigens / Q000276:immunology; D006801:Humans; D007144:Immunoglobulin J-Chains / Q000737:chemistry; D007135:Immunoglobulin Variable Region; D008285:Major Histocompatibility Complex / Q000276:immunology*; D008969:Molecular Sequence Data; D015394:Molecular Structure; D010446:Peptide Fragments / Q000276:immunology*; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000235:genetics*; D013744:Tetanus Toxin / Q000276:immunology*
D000939:Epitopes; D006684:HLA-DR Antigens; D007144:Immunoglobulin J-Chains; D007135:Immunoglobulin Variable Region; D010446:Peptide Fragments; D016693:Receptors, Antigen, T-Cell, alpha-beta; D013744:Tetanus Toxin