Molecular and structural analysis of the panallergen profilin B cell epitopes defined by monoclonal antibodies

Abstract

Interactions of five mouse mAb (10A4, 5F2, 9A7, 9G4 and 3H8) and sunflower profilin were characterized using synthetic overlapping peptides. All the continuous B cell epitopes analyzed in this work were 6-10 amino acids in length, and clustered at the N- and C-terminal alpha-helices and a two-stranded segment composed of residues 40-50. Mutational analysis of the epitopes revealed that single amino acid changes within these peptides had dramatic effects on IgG-binding characteristics. A three-dimensional molecular model of sunflower profilin was generated by homology modeling based on the crystal structure of Arabidopsis thaliana profilin. All but one of the murine B cell epitopes defined in this work were located on the surface of the profilin molecule in the alpha-helices (10A4 and 3H8) or in the turns (5F2 and 9G4). In contrast, 9A7 epitope was located in the profilin core and partially buried by the C-terminal. Two mAb (5F2 and 10A4) inhibited the binding of anti-profilin human IgE up to 52%. In contrast, mAb 3H8 seemed to enhance the binding of anti-profilin IgE of sera from allergic patients.

Narrow‐leafed lupin (Lupinus angustifolius L.) β‐conglutin proteins modulate the insulin signaling pathway as potential type 2 diabetes treatment and inflammatory‐related disease amelioration

“…In contrast, B-cell epitopes are either linear or conformational and are located on the surface of the molecule accessible to antibodies. The extension of the epitope may range from 5 to 8 (or even more) amino acids for IgE to be able of binding to the epitope [60][61][62][63]. However, we have found linear B-cell epitopes in lupin β-conglutins and the other legume allergens with a wide range of amino acid lengths, and overlapping with conformational epitopes.…”

Structural, Functional, and Immunological Characterization of Profilin Panallergens Amb a 8, Art v 4, and Bet v 2

“…For Cuc m 2 and Hel a 2 (profilin from sunflower pollen), it was experimentally demonstrated that the IgE biding epitopes overlap significantly with areas of the molecules participating in formation of the protein⅐protein complexes (Fig. 9, C and D) (43,44). The residues forming these epitopes in Cuc m 2 and Hel a 2 are also highly conserved in Amb a 8, Art v 4, and Bet v 2.…”

“…D, epitopes identified in Hel a 2.0101. The epitopes are labeled using a convention used in the original paper reporting these epitopes (43).…”

Profilins: Mimickers of Allergy or Relevant Allergens?

“…Several studies have addressed the location and characterization of IgE epitopes on profilins [46,47,48]. Fedorov et al [49] mapped Bet v 2 IgE epitopes on the N- and C-terminal α-helices and on a segment of the protein containing two strands of the β-sheet.…”