Lactiplantibacillus plantarum YY-112 ameliorates mouse immunosuppression by enhancing B/T-cell activation and maintaining Th1/Th2 homeostasis

In recent years, the development of immunosuppression has become common, and probiotics are a vital immunomodulatory strategy. This study evaluated the alleviating effect of Lactiplantibacillus plantarum ( L. plantarum ) YY-112 on cyclophosphamide-induced immune imbalance and resolved the possible mechanism of action. L. plantarum YY-112 at 10 9 CFU/mL lowered loss of body weight and alleviated splenic injury, intestinal injury, and inflammation, according to the hematoxylin and eosin staining. Biochemical results showed that 10 9 CFU/mL L. plantarum YY-112 increased interleukin-10 and immunoglobulin M levels and decreased interferon-γ levels. Additionally, the immunoregulatory effect at the molecular levels of L. plantarum YY-112 was analyzed by transcriptome sequencing. L. plantarum YY-112 significantly upregulated Cr2 and downregulated C5aR1 to regulate the complement system; downregulated S100a8 , S100a9 , and Mmp9 to inhibit neutrophil aggregation; upregulated Cd19 , Cd72 , Cd3e , Cd28 , Cd80 , Cd8a , and histocompatibility-2-related genes to regulate B- and T-cell activation; and upregulated Xiap , Malt1 , Ikbkb , Mapk11 , Mef2c , Mapk12 , Ras , and Myc to activate immune signaling pathways. Furthermore, L. plantarum YY-112 improved intestinal microbial structure and reduced enrichment of Lachnospiraceae_NK4A136_group , norank_f_Lachnospiraceae , Desulfovibrio , Colidextribacter , and Helicobacter . In conclusion, these findings offer valuable insights into the potential mechanisms through which L. plantarum YY-112 regulates immune imbalance.