Previous experiments in our laboratory have demonstrated that there is a marked restriction on the TCR beta-chain usage in DBA/2 mice in response to the sperm whale myoglobin (SpWMb) determinant 110-121, predominated by the use of the Vbeta8.2 gene element. We analyzed the response of mice that had been genetically depleted of Vbeta8+ T cells by generating a DBA/2 line that carries the Vbeta(a) TCR haplotype. Despite the very limited TCR repertoire expressed by DBA/2Vbeta(a) mice, they made an excellent response after immunization with the SpWMb 110-121 peptide. Data presented in this manuscript demonstrate that there is an equally restricted TCR Vbeta-chain utilization in the T-cell response to the determinant SpWMb 110-121 in DBA/2Vbeta(a) mice. Unexpectedly, there was a shift of MHC restriction of this determinant to T cells in the Vbeta(a) strain when compared with the Vbeta(b) strain of DBA/2 mice. We had previously demonstrated that DBA/2 mice utilized both the hybrid Ealpha(d)Abeta(d) MHC molecule as well as the conventional Aalpha(d)Abeta(d) molecule as presenting elements in response to SpWMb 110-121. Data presented in this manuscript demonstrate that the T-cell response in DBA/2Vbeta(a) mice is entirely restricted by the Aalpha(d)Abeta(d) MHC class II molecule. By analyzing a panel of SpWMb 110-121-specific T-cell clones from DBA/2Vbeta(a) mice, we were able to study the TCR repertoire expressed on T cells from mice that lack the Vbeta8.2 gene. The Vbeta usage by the panel of clones analyzed was remarkably homogeneous. Thirteen of the 17 clones analyzed used the Vbeta1 gene segment. Perhaps more striking was the junctional region nucleotide and amino acid sequences that were shared among these clones and that were similar to the Vbeta8.2 clones analyzed previously. All clones assayed used the Jbeta2.6 element, as did the great majority of the Vbeta8.2 clones analyzed from DBA/2 (and B10.D2) Vbeta(b) mice. Importantly, in each strain of mice, irrespective of the Vbeta utilized, each TCR appeared to have selected an acidic amino acid in the beta-chain at position 100. By analyzing the relationship between the structure of the TCR beta-chain and T-cell functional specificity, utilizing a panel of monosubstituted peptides, it has been possible to suggest structure/function relationship between TCR elements and specific amino acid residues in the determinant SpWMb 110-121.
SELECTION FOR AMINO-ACID-SEQUENCE AND J-BETA-ELEMENT USAGE IN THE BETA-CHAIN OF DBA 2V BETA(B)-DERIVED AND DBA 2V BETA(A)-DERIVED MYOGLOBIN-SPECIFIC T-CELL CLONES
RUBERTI G;
1993
Abstract
Previous experiments in our laboratory have demonstrated that there is a marked restriction on the TCR beta-chain usage in DBA/2 mice in response to the sperm whale myoglobin (SpWMb) determinant 110-121, predominated by the use of the Vbeta8.2 gene element. We analyzed the response of mice that had been genetically depleted of Vbeta8+ T cells by generating a DBA/2 line that carries the Vbeta(a) TCR haplotype. Despite the very limited TCR repertoire expressed by DBA/2Vbeta(a) mice, they made an excellent response after immunization with the SpWMb 110-121 peptide. Data presented in this manuscript demonstrate that there is an equally restricted TCR Vbeta-chain utilization in the T-cell response to the determinant SpWMb 110-121 in DBA/2Vbeta(a) mice. Unexpectedly, there was a shift of MHC restriction of this determinant to T cells in the Vbeta(a) strain when compared with the Vbeta(b) strain of DBA/2 mice. We had previously demonstrated that DBA/2 mice utilized both the hybrid Ealpha(d)Abeta(d) MHC molecule as well as the conventional Aalpha(d)Abeta(d) molecule as presenting elements in response to SpWMb 110-121. Data presented in this manuscript demonstrate that the T-cell response in DBA/2Vbeta(a) mice is entirely restricted by the Aalpha(d)Abeta(d) MHC class II molecule. By analyzing a panel of SpWMb 110-121-specific T-cell clones from DBA/2Vbeta(a) mice, we were able to study the TCR repertoire expressed on T cells from mice that lack the Vbeta8.2 gene. The Vbeta usage by the panel of clones analyzed was remarkably homogeneous. Thirteen of the 17 clones analyzed used the Vbeta1 gene segment. Perhaps more striking was the junctional region nucleotide and amino acid sequences that were shared among these clones and that were similar to the Vbeta8.2 clones analyzed previously. All clones assayed used the Jbeta2.6 element, as did the great majority of the Vbeta8.2 clones analyzed from DBA/2 (and B10.D2) Vbeta(b) mice. Importantly, in each strain of mice, irrespective of the Vbeta utilized, each TCR appeared to have selected an acidic amino acid in the beta-chain at position 100. By analyzing the relationship between the structure of the TCR beta-chain and T-cell functional specificity, utilizing a panel of monosubstituted peptides, it has been possible to suggest structure/function relationship between TCR elements and specific amino acid residues in the determinant SpWMb 110-121.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
