Characterization of epitope specificities of reference antibodies used for the quantification of the birch pollen allergen Bet v 1

BACKGROUND

Accurate allergen quantification is needed to document the consistency of allergen extracts used for immunotherapy. Herein, we characterize the epitope specificities of two monoclonal antibodies used in an ELISA for the quantification of the major birch pollen allergen Bet v 1, established as a reference by the BSP090 European project.

METHODS

The ability of mAbs 5B4 and 6H4 to recognize Bet v 1 isoforms was addressed by immunochromatography. The capacity of each mAb to compete with patients' IgE for binding to Bet v 1 was measured by ELISA inhibition. Epitope mapping was performed by pepscan analysis, site-directed mutagenesis, and hydrogen/deuterium exchange-mass spectrometry.

RESULTS

The 5B4 epitope corresponds to a peptide sequence (I56-K68) overlapping with the binding sites of patients' serum IgEs. Mutation of residues P59, E60, and K65 abolishes 5B4 binding to Bet v 1 and reduces the level of IgE recognition. In contrast, 6H4 recognizes a conformational epitope lying opposite to the 5B4 binding site, involving residues located in segments I44-K55 and R70-F79. Substitution of E45 reduces the binding capacity of 6H4, confirming that it is critical for the interaction. Both mAbs interact with >90% of Bet v 1 content present in the birch pollen extract, while displaying a weak cross-reactivity with other allergens of the PR-10 family.

CONCLUSIONS

MAbs 5B4 and 6H4 recognize structurally distinct epitopes present in the vast majority of Bet v 1 isoforms. These results support the relevance as a reference method of the Bet v 1-specific quantitative ELISA adopted by the European Pharmacopoeia.

Charter for disabled people using hospitals: a completed access audit cycle

This completed audit cycle assessed access for disabled people to a district general hospital, in relation to standards laid down in the Royal College of Physicians Charter for Disabled People using Hospitals. The project was effective in demonstrating problems and implementing change to overcome them. It was also useful in raising disability awareness in the young investigators, who easily recognised the shortcomings in facilities for disabled people, and is proposed as a possible model for inclusion in medical undergraduate training programmes to raise disability awareness amongst a new generation of doctors.

Cybersemiotics: a transdisciplinary framework for information studies

This paper summarizes recent attempts by this author to create a transdisciplinary, non-Cartesian and non-reductionistic framework for information studies in natural, social, and technological systems. To confront, in a scientific way, the problems of modern information technology where phenomenological man is dealing with socially constructed texts in algorithmically based digital bit-machines we need a theoretical framework spanning from physics over biology and technological design to phenomenological and social production of signification and meaning. I am working with such pragmatic theories as second order cybernetics (coupled with autopolesis theory), Lakoffs biologically oriented cognitive semantics, Peirce's triadic semiotics, and Wittgenstein's pragmatic language game theory. A coherent synthesis of these theories is what the cybersemiotic framework attempts to accomplish.