Biomedical subjects

H Breiteneder

Publications and source records attributed to H Breiteneder.

111 records · Page 7Linked to original sources

PubMedDate not supplied

Cross-reacting allergens in tree pollen and pollen-related food allergy: implications for diagnosis of specific IgE.

BACKGROUND: A number of recombinant allergens are by now constituents of devices that can be routinely used for the detection of specific IgE. Therefore, the results of diagnostic procedures using conventional allergen extracts can be compared with those employing selected recombinant allergens. METHODS: Thirty-four sera from patients allergic to birch pollen were tested with the standard t3-CAP and rBet v 1a- and rBet v 2-CAP. cDNA was prepared by RT-PCR using primers according to the N terminus of purified allergens. Expression cDNA libraries were screened with IgE from selected patients. RESULTS: Twenty-four patients allergic to birch pollen showed the same RAST class with t3 as with rBet v 1a; 8 patients differed within 1 RAST class. In addition, 3 patients showed RAST class 3 with rBet v 2. Besides Bet v 1 and Bet v 2, 3 allergens from celery and avocado belonging to highly conserved protein families were cloned and sequenced. CONCLUSIONS: rBet v 1a can be expected to represent an excellent tool for the diagnosis of patients allergic to birch pollen in Central, Northern, and Eastern Europe. Still, a much higher number of patients has to be tested. For their high degree of conservation, further protein families have to be identified to explain cross-reactivities of birch pollen allergens other than Bet v 1 and Bet v 2 with, e.g., allergens from vegetable food.

Allergens↗

PubMedDate not supplied

Isoforms of atopic allergens with reduced allergenicity but conserved T cell antigenicity: possible use for specific immunotherapy.

BACKGROUND: We analyzed the T cell activation potency and the IgE-binding properties (allergenicity) of nine isoforms of Bet v 1, the major allergen of birch pollen. METHODS: The capacity of recombinant Bet v 1 isoforms to bind serum IgE from allergic patients was evaluated by immunoblot experiments and skin prick tests. The potency of Bet v 1 isoallergens to activate T lymphocytes from birch-pollen-allergic patients was assayed using allergen-specific T cell clones. RESULTS: According to their ability to bind IgE from allergic patients in immunoblot experiments, Bet v 1 isoforms can be grouped into high-IgE-binding molecules and molecules with low/no IgE-binding activity. Representatively, isoform d was used in skin tests. Skin prick tests revealed no potency of this isoform to induce wheal and flare reactions in the skin of birch-pollen-allergic individuals. In contrast, isoform a and natural Bet v 1 displayed high allergenicity in vivo. On the other hand, Bet v 1 isoform d (low allergenicity) displayed significant higher T cell activation potency when compared to isoform a (high allergenicity). CONCLUSION: Based on these findings, we propose a new form of specific immunotherapy using hypoallergenic recombinant allergen isoforms.

Allergens↗

PubMedDate not supplied

T cell receptor CDR3 sequences and recombinant T cell receptors. Prerequisites for developing ligands to interfere with T cell receptor binding to the MHC/peptide complex.

BACKGROUND: The interaction of T cell receptors (TCRs) with peptide fragments bound to major histocompatibility complex (MHC) molecules is central to the initiation and propagation of most immune responses. In order to understand and control the molecular interactions underlying T cell recognition of MHC/peptide complexes, recent efforts have focused on the production of recombinant soluble forms of the TCR heterodimer. METHODS: TCRA variable (TCRAV) and TCRBV sequences used by human T cell clones were amplified by PCR, cloned and sequenced. The deduced amino acid sequences of the complementarity determining region (CDR) 3 loops of TCRs specific for the same allergenic epitope were compared. V region genes of a selected TCR were expressed as a single-chain (sc) molecule in the periplasm of Escherichia coli. RESULTS: Conserved amino acid motifs specific for allergenic peptides of Bet v 1 and Phl p 1 were identified in CDR3 sequences of TCRs. A recombinant scTCR was produced. The ratio of insoluble to soluble material was 1:1. The recombinant protein was of the correct size and showed no signs of degradation. CONCLUSIONS: Conservation of amino acid motifs in CDR3 loops of TCRs specific for the same allergen fragments indicated that the three-dimensional structure of the CDR3 was determined by the presented peptide. The recombinant scTCR will be used to identify ligands for the CDR3s from random peptide libraries to interfere with TCR binding to the MHC/peptide complex.

Allergens↗