Volume 4 Supplement 3

6th Drug Hypersensitivity Meeting (DHM 6)

Open Access

Beta lactam hypersensitivities

  • Marie Eliane* Azoury1,
  • Noémie* Scornet2,
  • Stéphanie Delluc3,
  • Sandrine Delarue-Cochin2,
  • Cathy Nhim1,
  • Bernard Maillere4,
  • Richard Weaver5,
  • Nancy Claude5,
  • Delphine Joseph2 and
  • Marc Pallardy1
Clinical and Translational Allergy20144(Suppl 3):P65

DOI: 10.1186/2045-7022-4-S3-P65

Published: 18 July 2014

Background

Allergic reactions to drugs are often unpredictable and can lead to serious side effects such as anaphylactic shock. According to the hapten hypothesis, any drug with a molecular weight lower than 1000 daltons cannot induce an immune response by itself and must be bound to a protein. Antigen presenting cells, such as dendritic cells (DC), internalize hapten-protein conjugates and digest them into peptides bound with the drug. The latter are then presented on HLA molecules to drug-specific T cells inducing specific-drug immune response. Knowing that drugs provoke IgE mediated hypersensitivity reactions in treated patients, the CD4+ T-cell response to benzylpenicillin (BP) was investigated. The objectives of this study were to evaluate the frequency of naïve CD4+ T cells specific to BP and to identify BP-haptenized peptides responsible for T lymphocyte activation.

Method

Since BP is known to bind covalently to proteins, such as Human Serum Albumin (HSA), HSA-BP bio-conjugates were synthesized at basic pH (pH=10.8). Seventeen BP binding-sites on HSA were then identified using mass-spectrometry, and 12 BP-haptenized peptides of 15 mer long potentially presented to T-cells via HLA class II molecules were identified and synthetized. Naïve CD4+ T cells from non-allergic donors were stimulated once a week with autologous DC loaded with HSA-BP or with peptide-BP to amplify respectively HSA-BP- or peptide-BP-specific T cells. Activation of specific CD4+ T cells was detected using interferon- EliSpot and their frequency was calculated using the Poisson distribution law.

Results

The results of the CD4+ T-cell response to BP were as follows:

- Detection of HSA-BP-specific CD4+ T cells in 12 out of 13 tested donors with a mean frequency of 0.26 cells/million of circulating CD4+ T cells

- Identification of 17 binding sites of BP on HSA

- Specific naïve CD4+ T cells recognized at least 3 specific peptides, from HSA, haptenized by BP.

Conclusion

This study showed the capacity of HSA-BP to be recognized by naïve T-cells from multiple healthy donors irrespective of their HLA typing and the possibility to identify BP-haptenized peptides involved in the allergic reaction to BP.

Authors’ Affiliations

(1)
UniverSud, Inserm UMR996
(2)
UniverSud, UMR CNRS8076
(3)
Platine Pharma service
(4)
CEA, IbiTecS, Simopro
(5)
Institut de Recherches Internationales Servier

Copyright

© Azoury et al; licensee BioMed Central Ltd. 2014

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

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