The bursa of Fabricius is an acknowledged central humoral immune organ unique to birds， which is vital to B cell differentiation and antibody production. However， the function and mechanism of the biological active peptide isolated from bursa on B cell development and autophagy were less reported. In this study， we isolated a new oligopeptide with nine amino acids Leu-Met-Thr-Phe-Arg-Asn-Glu-Gly-Thr from avian bursa following RP-HPLC， MODIL-TOP-MS， and MS/MS， which was named after BP9. The results of immunization experiments showed that mice injected with 0.01 and 0.05 mg/mL BP9 plus JEV vaccine generated the significant increased antibody levels， compared to those injected with JEV vaccine only... More
The bursa of Fabricius is an acknowledged central humoral immune organ unique to birds， which is vital to B cell differentiation and antibody production. However， the function and mechanism of the biological active peptide isolated from bursa on B cell development and autophagy were less reported. In this study， we isolated a new oligopeptide with nine amino acids Leu-Met-Thr-Phe-Arg-Asn-Glu-Gly-Thr from avian bursa following RP-HPLC， MODIL-TOP-MS， and MS/MS， which was named after BP9. The results of immunization experiments showed that mice injected with 0.01 and 0.05 mg/mL BP9 plus JEV vaccine generated the significant increased antibody levels， compared to those injected with JEV vaccine only. The microarray analysis on the molecular basis of BP9-treated immature B cell showed that vast genes were involved in various immune-related biological processes in BP9-treated WEHI-231 cells， among which the regulation of cytokine production and T cell activation were both major immune-related processes in WEHI-231 cells with BP9 treatment following network analysis. Also， the differentially regulated genes were found to be involved in four significantly enriched pathways in BP9-treated WEHI-231 cells. Finally， we proved that BP9 induced the autophagy formation， regulated the gene and protein expressions related to autophagy in immature B cell， and stimulated AMPK-ULK1 phosphorylation expression. These results suggested that BP9 might be a strong bursal-derived active peptide on antibody response， B cell differentiation， and autophagy in immature B cells， which provided the linking among humoral immunity， B cell differentiation， and autophagy and offered the important reference for the effective immunotherapeutic strategies and immune improvement.
