Immunoadjuvant Effects Of Probiotics Genomic DNA

The highly pathogenic Avian Influenza Virus (AIV) H5N1subtype seriously fall theglobal economy and threatened the human health since it broke out in Hong Kong in1997.The high pathogenicity and high variability of AIV H5N1raised the difficulties of AIVvaccine R&D and application. So studies on the vaccine adjuvant with the capability ofenhancing the host whole immunity, resisting the cross infection and extending the protectivephase against AIV H5N1would be quite meaningful. As the novel nucleotide adjuvant,probiotics genomic DNA has the potential to enhance the immune effects induced by thevaccine, so the development of this novel adjuvant is quite valuable.In this study, many kinds of probiotics strains had been chose and their genomic DNAhad been used as AIV oil emulsion vaccine adjuvants. The further comparison withadjuvanticity of pathogenic bacterial genomic DNA and CpG oligodeoxynucleotide (CpGODN) had been firstly carried out. This study aimed to find one effective adjuvant and itsdelivery way by investigating the humoral, cellar immune responses and cytokines secretionunder different administration ways. Results indicated that when probiotics genomic DNA(Enterococcus faecalis, Enterococcus faecium, Lactobacillus rhamnosus, Bifidobacteriumbifidum, Bacillus cereus), pathogenic bacteria genomic DNA (gram-negative E.coli andgram-positive Staphylococcus aureus) and CpG ODN were injected with AIV oil emulsionvaccine at the same site, the hemagglutination inhibition (HI) titre had be extremely reduced,while lymphocyte activity, phagocytic activity of macrophage and the concentrations ofserum IFN-γ and IL-10had been slightly increased. When probiotics Enterococcus faecalisFQ68genomic DNA, pathogenic E.coli and Staphylococcus aureus genomic DNA and CpGODN were incorported into AIV oil emulsion vaccine, CpG ODN and FQ68genome DNAcould enhance the HI titre, serum IgG titre and IFN-γ concentration, while reduce the IL-10concentration. In this case, the adjuvanticity of CpG ODN was more significant than that ofFQ68genomic DNA. While the immunoadjuvant effects induced by pathogenic E.coli andStaphylococcus aureus genomic DNA were worse. These data suggest that, depending on theimmunization approaches, nucleotide adjuvants could exert distinct immune effects in chickens immunized with AIV H5N1oil emulsion vaccine: the separate administration ofadjuvants to vaccine had not shown better adjuvanticity, while the prior incorporation of CpGODN or probiotics genome into the vaccine could augment both the humoral and Th1typeimmune responses, and CpG ODN was better than the nature bacterial genomic DNA.Furthermore, this study preliminarily demonstrated that co-injection of CpG motif and antigencould modulate the immunity towards Th1/Th2mixed response with a tendency towards Th1type response in chicken, which changed the traditional ways of host immune systemresponses to vaccine.