The immunomodulatory functions and molecular mechanism of a new bursal heptapeptide (BP7) in immune responses and immature B cells.

The bursa of Fabricius (BF) is the acknowledged central humoural immune organ unique to birds and plays a vital role in B lymphocyte development. In addition, the unique molecular immune features of bursal-derived biological peptides involved in B cell development are rarely reported. In this paper, a novel bursal heptapeptide (BP7) with the sequence GGCDGAA was isolated from the BF and was shown to enhance the monoclonal antibody production of a hybridoma. A mouse immunization experiment showed that mice immunized with an AIV antigen and BP7 produced strong antibody responses and cell-mediated immune responses. Additionally, BP7 stimulated increased mRNA levels of sIgM in immature mouse WEHI-231 B cells. Gene microarray results confirmed that BP7 regulated 2465 differentially expressed genes in BP7-treated WEHI-231 cells and induced 13 signalling pathways and various immune-related functional processes. Furthermore, we found that BP7 stimulated WEHI-231 cell autophagy and AMPK-ULK1 phosphorylation and regulated Bcl-2 protein expression. Finally, chicken immunization showed that BP7 enhanced the potential antibody and cytokine responses to the AIV antigen. These results suggested that BP7 might be an active biological factor that functions as a potential immunopotentiator, which provided some novel insights into the molecular mechanisms of the effects of bursal peptides on immune functions and B cell differentiation.

The Inducing Role and Molecular Basis of Bursal Hexapeptide (BHP) on Avian Immature B Cell.

BACKGROUND: The Bursa of Fabricius is an acknowledged central humoral immune organ unique to birds, which provides an ideal research model on the immature B cell development. OBJECTIVE: In this article, our motivation is to study the role on sIgM and establish the molecular basis and functional processes of Bursal Hexapeptide (BHP) in avian immature B cells DT40 cell lines. METHODS: In this article, we detected the expressions of sIgM mRNA with qPCR in DT40 cells with BHP treatment, and investigated the gene expression profiles of BHP-treated DT40 cells, employing microarray analyses. Also, to validate the differentially expressed genes, we performed KEGG pathway and Gene Ontology analysis in the BHP-treated DT40 cells. Finally, we comparatively analyzed the similar regulated genes and their involved immune functional processes between DT40 cell and mouse immature B cell line WEHI231 cell with BHP treatment. RESULTS: Following the proposed framework, we proved that the BHP enhanced the mRNA expression levels of IgM in DT40 cells, and induced 460 upregulated genes and 460 downregulated genes in BHP-treated DT40 cells. The pathway analysis showed that the differentially regulated genes in DT40 cell line with BHP treatment were involved in 12 enrichment pathways, in which Toll-like receptor signaling pathway was the vital pathways, and cytokine-cytokine receptor interaction and Jak-STAT signaling pathway were another two important pathways in BHP-treated DT40 cells. Moreover, BHP induced the immune related biological processes in BHP-treated DT40 cells, including T cell related, cytokine related, lymphocyte related, and innate immune response GO terms. Finally, the comparatively analysis showed that there were two downregulated genes GATA3 and IFNG to be found co-existed among the differentially expressed genes in BHP-treated DT40 cell and WEHI231 cells, which shared some same immune related functional processes in both cell lines. CONCLUSION: After the applying the framework, we proved the inducing roles and the gene expression profiles of BHP on avian immature B cells, and verified some molecular basis from the KEGG and GO analysis. These results provided the insight for mechanism on immature B cell differentiation, and offer the essential direction for the vaccine improvement.

The Functions and Mechanism of a New Oligopeptide BP9 from Avian Bursa on Antibody Responses, Immature B Cell, and Autophagy.

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.

The Functions of Bursal Hexapeptide (BHP) on Immune Response and the Molecular Mechanism on Immature B Cell.

BACKGROUND: The bursa of Fabricius (BF) is an acknowledged central immune organ, and is important to B cell differentiation. Bursal hexapeptide (BHP) is the recently reported bursalderived peptide, while its inducing function on immune response is uncertain. OBJECTIVES: The main objective of this study was to analyze the immune responses to JEV vaccine in mice induced by BHP plus JEV vaccine, and to detect the signal and biological functions of BHP on immature B cells. METHODS: Mice were immunized with Japanese encephalitis virus (JEV) vaccine and BHP from 0.01 mg/mL to 0.25 mg/mL to detect antibody response and cellular immune response, respectively. The production of IgG, IgG1 and IgG2a specific to JEV in serum from immunized mice were measured by ELISA, and T cell subpopulation from immunized mice were detected with using fluorochrome conjugated mAbs of the corresponding PE-Cys/FITC/PE by flow cytometry. Spleen cells from all immunized mice were harvested after one week of second immunization for lymphocyte proliferation assay. Mouse immature B cell WEHI-231 cell was treated with 0.01µg/mL BHP for 4h, and analyzed the involved biological function and pathway of differentially expressed genes with gene microarray. RESULTS: BHP co-immunization with JEV vaccine generated significant increased antibody levels, neutralizing antibody titers and spleen lymphocyte viability, compared to that of vaccine control. The subpopulations of T cells in spleen lymphocytes were significantly modified in the mice coimmunized with JEV vaccine and BHP. The analysis results of gene expression profiles of WEHI- 231 mouse immature B cells with BHP treatment showed that the regulated genes with BHP treatment were involved various immune related biological functions, including proliferation and activation of lymphocyte and T cell, T cell mediated immunity and regulation of adaptive immune response. Furthermore, BHP stimulated three significant enriched pathways, including amphetamine addiction, long-term potentiation, and RIG-I-like receptor signaling pathway. CONCLUSION: Our results indicated BHP induced significant humoral and cellular immunity to JEV vaccine, and regulated various biological processes and signalling related to immune activation in immature B cells. These results proposed the immunomodulatory function and mechanism of BHP on immune induction, which provided the novel insight on the candidate reagent for immune improvement.

The potential molecular effects of bursal septpeptide II on immune induction and antitumor activity.

The bursa of Fabricius (BF) is the acknowledged central humoral immune organ in birds. Bursal septpeptide II (BSP-II) is an immunomodulatory bioactive peptide isolated from BF. To understand the effects of BSP-II on immune induction, gene expression profiles of hybridoma cells treated with BSP-II were evaluated. Pathway analysis showed that regulated genes were involved in cytokine-cytokine receptor interactions, T cell receptor signaling pathway, and pathway in cancer. It was observed that BSP-II reduced tumor cells proliferation and stimulated p53 expression. These results indicate potential mechanisms underlying the effects of the humoral immune system on immune induction, including antitumor activities. Our study has provided a novel insight into immunotherapeutic strategies for treating human tumors.