Abstract
Allergic disease is one of the most important and common health problems worldwide. We have previously demonstrated that a fig leaf-derived lactic acid bacterium Lactobacillus (Lb.) paracasei IJH-SONE68 produces a novel exopolysaccharide (EPS). Furthermore, we have shown that the EPS inhibits the catalytic activity of hyaluronidase (EC 3.2.1.36) promoting inflammatory reactions. To evaluate the anti-allergy and anti-inflammatory effects of the EPS, in the present study, we employed the picryl-chloride-induced delayed-type (type IV) allergy model mice, which is used to evaluate the contact dermatitis. Oral administration of the EPS was observed to reduce the ear swelling in the model mice. We also observed that the overexpression of ear interleukin-4 (T helper (Th) 2 cytokine) mRNA and the increase in serum immunoglobulin E (IgE) are repressed. However, the expression of interferon-γ (Th1 cytokine) was not accelerated in all of the allergen-challenged model mice. The improvement may be responsible for the Th2 downregulation rather than the Th1 upregulation. In addition, the symptom of immediate-type (type I) allergy model mice was improved by oral administration of the IJH-SONE68 cell (data not shown). We can conclude that the IJH-SONE68-derived EPS is useful to improve the type I and IV allergies including atopic dermatitis.
Highlights
Lactic acid bacteria (LABs) are typical probiotics that are an order of gram-positive and generally non-pathogenic bacteria
We have found by nuclear magnetic resonance (NMR) analysis that the neutral EPS mainly consists of α-1,6 linked glycan chains made of N-acetylglucosamine (GlcNAc), demonstrating that the neutral EPS has a novel structure that has never been reported [12]
We evaluated whether the LAB cells and EPS fraction prevent or repress the Picryl chloride (PiCl)-induced delayed-type allergy (Figure 1B)
Summary
Lactic acid bacteria (LABs) are typical probiotics that are an order of gram-positive and generally non-pathogenic bacteria. Probiotics are defined as living microorganisms that confer health benefits to hosts such as humans [1]. LABs produce a large amount of lactic acid, sometimes together with acetate or ethanol [2]. Some LAB strains, which produce bacteriocin and functional substances, have health benefits for humans [3,4]. Mechnikov of the Pasteur Institute proposed the theory that aging is caused by toxic bacteria in the gut and that lactic acid could prolong life.
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