Molecular and functional analysis of the antigen receptor of Art v 1–specific helper T lymphocytes

Background

Ninety-five percent of patients with mugwort allergy are sensitized to Art v 1, the sole major allergen in mugwort (Artemisia vulgaris) pollen. Sixty-nine percent of patients recognizing the single immunodominant T-cell epitope Art v 1_25-36 have an HLA-DRB1*01 phenotype.

Objective

We studied cloning and functional expression of a human αβ T-cell receptor (TCR) specific for Art v 1_25-36.

Methods

TCR chains were RT-PCR amplified from an Art v 1_25-36–specific T-cell clone, retrovirally transferred, and functionally tested in Jurkat T cells or alternatively in peripheral blood T lymphocytes of nonallergic individuals.

Results

The α-chain of the TCR is composed of TRAV17 and TRAJ45 segments, and the β-chain uses TRBV18, TRBD1, and TRBJ2-7. Analyses of 23 other Art v 1–specific T-cell clones did not reveal preferential usage of the TRAV17, TRBV18, or other TCR gene families. Efficient TCR transfer into Jurkat T cells was shown by binding of TCR Vβ18–specific mAb and DRB1*0101/Art v 1 tetramers. Transgenic Jurkat T cells specifically recognized syngeneic EBV B cells pulsed with Art v 1_25-36 peptide and artificial antigen-presenting cells expressing invariant chain::Art v 1 fusion proteins. Moreover, transfer of the TCR into peripheral blood lymphocytes generated T cells that were Art v 1 reactive. Activation of transgenic T cells by artificial antigen-presenting cells was strictly dependent on costimulation.

Conclusion

For the first time, a detailed molecular and functional analysis of a human allergen-specific TCR is presented.

Key words: Type I allergy, mugwort pollinosis, Art v 1, human T-cell receptor, T-cell receptor transgenic T cells, artificial antigen-presenting cell

Abbreviations used: aAPC, Artificial antigen-presenting cell, CLIP, Class II–associated invariant chain peptide, FITC, Fluorescein isothiocyanate, HA, Influenza hemagglutinin, Ii, Invariant chain, PB, Peripheral blood, PBL, Peripheral blood lymphocytes, PE, Phycoerythrin, SEE, Staphylococcal enterotoxin E, SI, Stimulation index, TCR, T-cell receptor, tg, Transgenic, WT, Wild-type