IgE reactivity of a recombinant multi-epitope protein designed from allergens of interest in the tropics: Preliminary findings

Abstract

Introduction: Multi-epitope vaccines in recent years have shown promising immunomodulatory effects on different alterations of the immune system; being allergic diseases a field to be explored, particularly with house dust mite allergens (HDM) and nematodes such as A. lumbricoides which are common in allergic patients in tropical regions.

Objective: the objective of the present study was to design a multi-epitope protein from A. lumbricoides and APD allergens and to evaluate its IgE reactivity preliminarily.

Methos: using computational tools, a molecule containing multiple "T" epitopes of allergens derived from A. lumbricoides and APD was designed "in silico" This multi-epitope protein (MP1) was expressed using an E. coli system and purified by affinity chromatography using Ni-NTA agarose. Anti-MP1 and anti-HDM extract IgE reactivity was evaluated by Dot-Blot and indirect ELISA from sera of HDM-allergic patients and non-allergic individuals from Barranquilla-Colombia. Allergic individuals had a positive skin test to a standardized battery of inhaled allergens (EUROLINE - Ref: DP 3704-1601-1 E) and mite-specific IgE.

Results: multi-epitope (MP1) protein was expressed and purified with high purity. Dot-Blot result showed that all sera from allergic patients showed lower IgE reactivity to MP1 compared to HDM extract. By ELISA, significantly lower concentrations of anti-MP1 IgE (Median: 270.86 ng/ml; IQR: 90.3) were observed in contrast to anti-HDM IgE levels (Median: 988.5 ng/ml; IQR: 1117.6) in sera of patients allergic to HDM.

Conclusions: A protein composed of multiple epitopes of A. lumbricoides and HDM allergens was designed, expressed, and purified. Preliminary Dot-Blot results suggest that this molecule shows hypoallergenic properties with very low IgE reactivity compared to mite extract. Further functional studies are needed to understand better the immune response induced by this molecule.