RESUMO
T cell receptors (TCR) identify target cells presenting a ligand consisting of a major histocompatibility complex molecule (MHC) and an antigenic peptide. A considerable amount of evidence indicates that the TCR contacts both the peptide and the MHC components of the ligand. In fully differentiated T cells the interaction between the peptide and the TCR makes the critical contribution to eliciting a cellular response. However, during the positive selection of thymocytes the contribution of peptide relative to MHC is less well established. Indeed it has been suggested that the critical interaction for positive selection is between the TCR and the MHC molecule and that peptides can be viewed as either allowing or obstructing this contact. This predicts that a given TCR is capable of engaging multiple MHC/peptide complexes. In this study a system is described which detects simply engagement of the TCR by MHC/peptide complexes rather than the functional outcome of such interactions. Using this approach the extent to which peptides can influence contacts between the TCR and the MHC molecule has been examined. The results show that the TCR does in fact engage a wide range of ligands in an MHC-restricted but largely peptide-independent manner, suggesting that only a few peptides are able to prevent the TCR from contacting the MHC molecule.
Assuntos
Antígeno HLA-A2/metabolismo , Peptídeos/imunologia , Peptídeos/metabolismo , Receptores de Antígenos de Linfócitos T/metabolismo , Animais , Ligação Competitiva/efeitos dos fármacos , Ligação Competitiva/imunologia , Degranulação Celular/genética , Degranulação Celular/imunologia , Epitopos/genética , Antígeno HLA-A2/genética , Antígeno HLA-A2/farmacologia , Humanos , Leucemia Basofílica Aguda , Proteínas de Membrana/genética , Proteínas de Membrana/imunologia , Ratos , Receptores de Antígenos de Linfócitos T/antagonistas & inibidores , Receptores de Antígenos de Linfócitos T/genética , Receptores de Antígenos de Linfócitos T/imunologia , Proteínas Recombinantes de Fusão/imunologia , Proteínas Recombinantes/farmacologia , Transfecção , Células Tumorais CultivadasRESUMO
Intelligence and achievement test scores of 100 school-identified, learning-disabled boys were analyzed. WISC-R students were analyzed for strengths and weaknesses, and patterns were identified through factor analysis. The factor loadings, as well as WISC-R IQs, were used as predictor variables, and the Woodcock-Johnson Achievement cluster scores comprised the achievement variables. A stepwise multiple regression indicated that the most powerful intelligence predictor for all three areas of achievement was the WISC-R Performance IQ. Four factor patterns significantly increased the prediction of Woodcock-Johnson Written Language scores.
