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J Immunol Methods. 2015 Oct;425:37-44. doi: 10.1016/j.jim.2015.06.006. Epub 2015 Jun 14.

Unpredicted phenotypes of two mutants of the TcR DMF5.

Author information

1
Department of Cancer Immunology, Institute for Cancer Research, Oslo University Hospital Radiumhospitalet, Oslo, Norway.
2
Department of Cancer Immunology, Institute for Cancer Research, Oslo University Hospital Radiumhospitalet, Oslo, Norway; K.G. Jebsen Center for Cancer Immunotherapy and K.G. Jebsen Center for Inflammation Research, Institute for Clinical Medicine, University of Oslo, Norway.
3
Department of Cancer Immunology, Institute for Cancer Research, Oslo University Hospital Radiumhospitalet, Oslo, Norway; Department of Cellular Therapy, Oslo University Hospital Radiumhospitalet, Oslo, Norway. Electronic address: sebastw@rr-research.no.

Abstract

When a T-cell Receptor (TcR) interacts with its cognate peptide-MHC (pMHC), it triggers activation of a signaling cascade that results in the elicitation of a T cell effector function. Different models have been proposed to understand which parameters are needed to obtain an optimal activation of the signaling. It was speculated that improving the binding of a TcR could bring a stronger pMHC recognition, hence a stronger stimulation of the T cell. However, it was recently shown that an increase in affinity does not seem to be sufficient to guarantee improved functionality. A combination of factors is necessary to place the modified TcR in an optimal functional window. We here compared the binding parameters of two mutants of the melanoma antigen peptide MART-127-35 specific TcR DMF5. The first mutant was previously isolated by others in a screen for improved TcR. It was reported to have an increased CD8-independent activity. We confirmed these data and showed that the enhancement was neither due to change in half life (t1/2) nor Kd of the pMHC-TcR complex. The second mutant was designed based on a previous report claiming that a particular polymorphic residue in the TRAV12-2 chain was stabilizing the TcR. We created a DMF5 mutant for this residue and showed that, unexpectedly, this TcR had acquired a reduced overall activity although the TcR-pMHC complex was more stable when compared to the TcR wild type complex (increased t1/2). In addition, the soluble TcR form of this mutant bound target cells less efficiently. From this we concluded that kinetic parameters do not always predict the superior functionality of mutant TcRs.

KEYWORDS:

Antigen; Peptide; Peptide-HLA complex; Soluble TcR; T-cell receptor; TcR; sTcR

PMID:
26079729
DOI:
10.1016/j.jim.2015.06.006
[Indexed for MEDLINE]

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