Lactococcus lactisharbouring Ara h 2.02 alleviates allergen‐specific Th2‐associated responses in sensitized mice

Abstract

Aim To study the prophylactic effect of recombinant Lactococcus lactis (rLl) harbouring Ara h 2.02 peanut allergen, in sensitized and challenged mice. Methods and Results Ara h 2.02 cDNA was cloned into pNZ8048 for heterologous expression in L. lactis. The purified recombinant allergen showed IgE binding comparable with native Ara h 2. Balb/c mice were fed with either recombinant (rLl), nonrecombinant L. lactis (Ll) or NaHCO3 (Sham) prior to sensitization and challenged with rAra h 2.02, whereas the baseline group was only fed with Ll. Allergen‐specific immunoglobulin and splenocyte cytokines responses were determined for each mouse. Mice fed with either Ll or rLl showed significant alleviation of IgE and IgG1 compared to the Sham group. Despite no significant decrease in Th2 (IL‐4, IL‐13, IL‐6) or increase in Th1 (IFN‐γ) cytokines, both groups showed lower IL‐10 level, while the IL‐4 : IFN‐γ ratio was significantly lower for rLl compared to Ll group. Conclusions Oral administration of rLl harbouring Ara h 2.02 demonstrated alleviation of Th2‐associated responses in allergen‐challenged mice and a possible added allergen‐specific prophylactic effect. Significance and Impact of the Study Ara h 2.02 coupled with the intrinsic properties of probiotic L. lactis as a delivery vehicle can be explored for the development of a commercially scalable vaccine.

The Major Peanut Allergen Ara h 2 Produced in Nicotiana benthamiana Contains Hydroxyprolines and Is a Viable Alternative to the E. Coli Product in Allergy Diagnosis

“…IgE from all peanut allergic patients involved in the study recognized the E. coli -made rAra h 2; thus, authors reported this recombinant allergen as a promising candidate for its use in allergy diagnosis (Astier et al, 2006 ). Although tested with sera from peanut allergic mice, IgE-binding of natural Ara h 2 did not differ from those made in E. coli or L. lactis (Chan et al, 2020 ). Another study reported significantly weaker recognition of the E. coli -made rAra h 2 by IgE of allergic patients in comparison to the natural protein (Lew and Lim, 2016 ).…”

“…Isolated natural allergens have been largely replaced by recombinant allergens produced in prokaryotic hosts, mainly in Escherichia coli (Larsen et al, 2020 ) due to easier production, simpler characterization and standardization of the products, and the absence of cross-contamination with other allergens from the same source, which could influence the test results (Lowenstein and Larsen, 2001 ; Sancho et al, 2010 ; Curin et al, 2017 ). Escherichia coli and Lactococcus lactis have been utilized to produce rAra h 2 with low-to-moderate IgE-binding capacities (Astier et al, 2006 ; Lew and Lim, 2016 ; Chan et al, 2020 ). IgE from all peanut allergic patients involved in the study recognized the E. coli -made rAra h 2; thus, authors reported this recombinant allergen as a promising candidate for its use in allergy diagnosis (Astier et al, 2006 ).…”