Figure 7

Pretreatment with probioticL. johnsoniiL531 protects the intestine fromS. Infantis infection by regulating ER protein expression and CCR6⁺T-cell responses.Salmonella Infantis infection is usually associated with dysbiosis [4]. Intragastric administration of L. johnsonii L531 decreased the abundance of total bacteria and reduced the colonization of Salmonella in the intestine [10]. During S. Infantis infection, L. johnsonii L531 attenuates ER stress and inhibits the production of lipocalin 2 in the intestine. In the intestinal mesenteric lymph nodes, S. Infantis elevated the proportion of CCR6⁺ IFNγ⁺ T cells, and L. johnsonii L531 induced an increase in CD4⁺ CCR6⁺ T cells in response to S. Infantis challenge. Challenge with S. Infantis decreased the percentage of CD4⁻ CCR6⁺ T cells but increased the percentage of CCR6⁻ IFNγ⁺ T cells in peripheral blood. The Salmonella-associated ER stress ameliorated by L. johnsonii L531 and its regulation of T cell responses during S. Infantis infection contribute to inhibition of inflammation development and maintenance of intestinal homeostasis.