Polysaccharides L900/2 and L900/3 isolated from Lactobacillus rhamnosus LOCK 0900 modulate allergic sensitization to ovalbumin in a mouse model.

Here, we compared the abilities of polysaccharides L900/2 and L900/3, which were previously isolated from Lactobacillus rhamnosus LOCK 0900, to modulate the immune response to bystander antigens in a mouse model of ovalbumin (OVA) sensitization. In vivo, both polysaccharides reduced the levels of OVA-specific IgE, IgE-dependent basophil degranulation and IgG2a antibodies, but had no effect on the levels of OVA-specific IgA or IgG1. Interestingly, both polysaccharides triggered recall cellular responses with distinct properties. L900/3 significantly suppressed the OVA-induced upregulations of IL-4, IL-5, IL-10 and IL-13 in re-stimulated spleen cells and mesenteric lymph nodes. Our findings support and expand on our previous in vitro studies by demonstrating that polymer L900/3 might modulate the Th1/Th2 balance and could be a promising candidate molecule for preventing allergic sensitization.