The Alleviative Effect of Oral Administration of Lactiplantibacillus plantarum 22A-3 on Allergic Contact Dermatitis in Mice

Background/Introduction: The oral administration of Lactiplantibacillus plantarum 22A-3 (LP22A-3) could suppress ear inflammatory edema in the mice sensitized with an allergy-induced chemical compound, 1-fluoro-2, 4-dinitrobenzene (DNFB). Method: In this study, we formulated a hypothesis that the homeostasis of immunocompetent cells might be associated with alleviating this inflammation. Results: Pro-/anti-inflammatory cytokines are involved in the cell differentiation in vitro. Our results showed that the accumulation of pro-inflammatory cytokines, TNF-α and IL-6 were attenuated by the administration of the LP22A-3, in which bacteria were inactivated by heating at 80 °C. On the other hand, the level of the anti-inflammatory one, IL-10, was maintained. These findings suggested that LP22A-3 could be induced to build anti-inflammatory conditions. Regarding the cell migration from the small intestine, we aimed to clarify the mechanism in more detail by conducting experiments using KikGR mice to track the migration of target cells. We found that the migration of CD11b+CD86+ cells from the ileum increased in the DNFB-induced allergic dermatitis in mice. Then, the oral LP22A-3 administration could reduce their levels in the ileum to baseline levels. On the other hand, the migration of CD11b+CD206+ cells was enhanced in the dermatitis mice. However, it was shown that the increase in migration of those cells was not influenced by the LP22A-3 administration. Furthermore, our results suggested that oral LP22A-3 administration inhibited the differentiation of CD4+ cells into IL-9-inducing cells. Conclusions: This study might show the potential of immunocompetent cell action for alleviating the inflammation. In addition, the oral LP22A-3 administration could be a promising alternative alleviative strategy for type-IV allergic disorders.