Versatile Application of Nanobodies for Food Allergen Detection and Allergy Immunotherapy

Abstract

The unique characteristics of camelid heavy-chain only antibody (HCAb) derived nanobodies (Nbs) have facilitated their employment as tools for research and application in extensive fields including food safety inspection, diagnosis and therapy of diseases, etc., to develop immune detecting techniques or alternative candidates of conventional antibodies as diagnostic and therapeutic reagents. The wide application in the fields of food allergen inspection and immunotherapy has not been addressed as not much results published in the literature. The robust properties and straightforward selecting strategy of Nbs impel the advantageous employment compared with monoclonal antibodies (mAbs) to establish immunoassay and serve as blocking antibodies to compete immunoglobulin E (IgE) binding epitopes on food allergens. More and more efforts have been invested to develop specific Nbs against food allergen proteins, such as macadamia allergen of Mac i 1, peanut allergen of Ara h 3, and lupine allergen of Lup an 1, which demonstrated the potential of Nbs for research and application in food allergen surveillance. Meanwhile, the paratopes of Nbs preferably targeting the unique epitopes of food allergens can provide more possibilities to serve as blocking antibodies to shield IgE binding epitopes for food allergy immunotherapy. Regardless, the research and application of Nbs in the field of food allergen and allergic reactions are expected to attract dramatic focus and produce promising research outputs.

Generation of high affinity ICAM-1-specific nanobodies and evaluation of their suitability for allergy treatment

“…Nasal and ocular epithelial cell surfaces are exposed to allergen quantities in the range of ng/day ( 55 ), thus stopping allergen penetration with rather low amounts of specific nanobodies topically applied to target organs of allergic rhinoconjunctivitis seems feasible. Increasing numbers of nanobodies specific for a variety of clinically relevant allergens are becoming available ( 27 – 30 , 56 , 57 ). It should therefore be possible to develop allergen/ICAM-1 nanobody constructs for diverse respiratory allergens that can be flexibly combined to protect patients against several different allergen sources.…”

“…However, to produce defined antibody constructs at reasonable expenses, smaller molecules generated at lower costs in Escherichia coli (E.coli) gathered interest. Accordingly, nanobodies (V HH domains) derived from heavy chain-only antibodies of camelids were shown to be versatile tools for diagnosis and treatment of various diseases and, more recently, for immunoassay development in the field of type I allergy ( 24 – 30 ). In addition, nanobodies have similar antigen affinities as monoclonal antibodies, are chemically and physically very stable, and have a simple structure ( i.e.…”

Recent advances of nanobody applications in diagnosis and detection

“…16 Another issue to consider, which may also occur with conventional antibodies, is the possibility of eliciting VHHs with a strong binding affinity for the coating haptens, but with weak or no recognition for the free analyte. 10 In any case, phage display technology represents a robust, efficient, and inexpensive approach that is particularly suitable for screening large-scale nanobodies. As the field of phage display continues to advance, the limitations of this technology in terms of stability, capacity, and diversity will be improved.…”

“… 17 However, a good assay may not be available without the selection of well‐designed haptens for screening, or without an adequate library of competitive ligands or “coating antigens” for assay development 16 . Another issue to consider, which may also occur with conventional antibodies, is the possibility of eliciting VHHs with a strong binding affinity for the coating haptens, but with weak or no recognition for the free analyte 10 . In any case, phage display technology represents a robust, efficient, and inexpensive approach that is particularly suitable for screening large‐scale nanobodies.…”

“…Furthermore, the FR of VHH shares more than 80% sequence homology with human VH of family III (VH3), but four highly conserved hydrophobic amino acids (V37, G44, L45, and W47) in FR2 of the human VH domain are substituted in VHH by more hydrophilic amino acids (F37, E44, R45, and G47) (Figure 1B). 10 These mutations increase the solubility and stability of autonomous VHH lacking the partner VL domain. 8 Two years after discovering camelid HCAbs, Greenberg et al 11 identified similar heavy chain-only antibodies (Immunoglobulin new antigen receptor, IgNAR) in cartilaginous fish.…”