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Sublingual immunotherapy (SLIT) has been introduced as a noninvasive and safer approach for allergen-specific immunotherapies. In this study we investigated the efficacy of oral immunotherapy with recombinant Salsola kali 1 protein (Sal k 1) on Th1/Th2 balance in a mouse model of allergy. Female Balb/c mice were intraperitoneally sensitized with rSal k1, followed by a respiratory challenge with 1% (w/v) rSal k1. The sensitized mice were subjected to SLIT using rSal K1 expressing Lactobacillus lactis strain for three weeks. Each week the experimental group underwent SLIT protocol twice. Finally, serum levels of specific immunoglobulins including IgE, IgG1 and IgG2a, as well as secretion of different cytokines from splenocytes including IL-2, IL-4, IL-10, IFNγ and TGFβ into culture media were measured by ELISA. Following immunotherapy, the levels of specific IgE and IgG1 in mice sera as well as IL-4 level in supernatant of splenocytes were significantly lower than allergic controls. While serum IgG2a, IgG2a/IgG1 ratio as well as concentration of IL-2, IL-10, IFNγ, and TGFβ were higher in the SLIT group compared to the controls. The histopathological examination of intestinal tissues revealed no sign of inflammatory response following SLIT. This study revealed that Th2 immune responses are reduced in allergic mice after feeding them with allergen expressing probiotic bacteria as a SLIT approach. Since the safety of this procedure was previously approved, thus, it seems that a similar protocol using human based probiotics could be applied for Salsola kali sensitive patients.

The Salsola kali pollen is considered the main cause of allergic sensitization in desert and semi-desert regions. We have constructed recombinant Lactococcus lactis producing Sal k1 protein with the aim of using it as a mucosal vaccine for specific immunotherapy. The Sal k1 gene was amplified, and transferred into a PNZ 8148 plasmid. The PNZ8148-Sal k1 recombinant plasmid was transformed into competent E.coli strain MC1061 for replication, and then was isolated and cloned into competent L. lactis by electroporation. The cloning was verified by PCR and gene sequencing. The production of recombinant Sal K1 (rSal K1) protein was induced by nisin. The rSal K1 protein was purified by affinity chromatography and dialysis, and confirmed by SDS-PAGE and western blot analyses. The recombinant L. lactis was successfully constructed. Production of a 40-kDa rSal k1 protein with the L. lactis was shown by sodium dodecyl sulfate-polyacrylamid gel electrophoresis (SDS-PAGE) analysis. In addition, western blot analysis using specific mouse anti-Sal k1 polyclonal antibodies and sensitive human sera verified the 40-kD protein as rSal k1 allergen. This study demonstrated that L. lactis may be used as a promising live delivery system for recombinant Sal k1 protein without altering its immunoreactivity; however, its efficacy in the context of the immune system is suggested to be pursued in future studies.

Air pollutants and their interaction with environmental allergens have been considered as an important reason for the recent increase in the prevalence of allergic diseases. The aim of this study was to investigate the traffic pollution effect, as a stressor, on Platanus orientalis pollen allergens messenger RNA (mRNA) and protein expression. P. orientalis pollen grains were collected along main streets of heavy traffic and from unpolluted sites in Mashhad city, in northeast Iran. The pollen samples were examined by scanning electron microscopy. To assess the abundance of pollen allergens (Pla or 1, Pla or 2, and Pla or 3) from polluted and unpolluted sites, immunoblotting was performed. Moreover, the sequences encoding P. orientalis allergens were amplified using real-time PCR. Scanning electron microscopy showed a number of particles of 150-550 nm on the surface of pollen from polluted sites. Also, protein and gene expression levels of Pla or 1 and Pla or 3 were considerably greater in pollen samples from highly polluted areas than in pollen from unpolluted areas (p < 0.05). In contrast, no statically significant difference in Pla or 2 protein and mRNA expression level was found between samples from the two areas. We found greater expression of allergens involved in plant defense mechanisms (Pla or 1 and Pla or 3) in polluted sites than in unpolluted ones. The high expression of these proteins can lead to an increase in the prevalence of allergic diseases. These findings suggest the necessity of supporting public policies aimed at controlling traffic pollution to improve air quality and prevent the subsequent clinical outcomes and new cases of asthma.