Enhanced immunoreactivity and preferential heterodimer formation of reassociated Fel d I recombinant chains

Structural Characterization of the Tetrameric form of the Major Cat Allergen Fel d 1

“…6,8 Several attempts with only partial success have been made to refold the separate peptide chains into a native-like allergen. [8][9][10][11][12] We have previously established in vitro conditions for the appropriate folding of recombinant Fel d 1 using a direct linkage of chain 1 to chain 2 (construct Fel d 1 (1 + 2)) and chain 2 to chain 1 (construct Fel d 1 (2 + 1)). 13 Both refolded recombinant Fel d 1 protein variants display an identical disulfide-bonding pattern and a comparable secondary structure to the native protein.…”

The Major Cat Allergen, Fel d 1, in Diagnosis and Therapy

“…T-cell epitopes should ideally be preserved so that the resulting hypoallergen will still be able to modify the allergen-specific immune response. The structure of Fel d 1 is known [33], and Fel d 1 has been extensively studied in terms of B- and T-cell epitopes [36,42,51] making it feasible to rationally design Fel d 1 hypoallergens. We have applied this approach on recombinant Fel d 1 [30] and created a series of Fel d 1 hypoallergen candidates with the aim to disrupt B-cell epitopes but leave T-cell epitopes intact (fig.…”

“…So far, information about major IgE-binding sites of Fel d 1 is lacking. Several studies have attempted to identify dominant Fel d 1 T-cell epitopes [36] in order to construct peptide-based vaccines [37,54,55,56]. Counsell et al [54] used T-cell lines from 53 cat-allergic subjects and mapped the T-cell reactivity to overlapping peptides spanning chain 1 and chain 2 of Fel d 1.…”

“…Over the years, Fel d 1 has been extensively characterized, both by biochemical and immunological methods such as CD spectrum [30] and amino acid sequencing [31], cloning [32], chrystallography [33,34,35], analysis of T-cell epitope repertoires [36,37], serological measurements of patients’ IgE antibodies [17,38], as well as epitope mapping by monoclonal antibodies [39,40,41]. …”

“…The concept was early applied on Fel d 1. Based on knowledge from T-cell epitope mapping studies of Fel d 1, 2 synthetic peptides of 27 amino acids comprising T-cell epitope-rich regions in Fel d 1 chain 1 were produced [36]. In the first clinical applications, the peptide vaccine, Allervax CAT, was shown to give a reduced symptom score after allergen challenge [69] and to shift the cytokine profile by decreasing the IL-4 production in Fel d 1-specific T cells [70,71].…”