Study On Adjuvants Of Mycoplasma Hyopneumoniae Inactivated Vaccine And Live Vaccine

Mycoplasmal pneumonia of swine, as a chronic porcine respiratory disease, widely spread in the world with high incidence. It can decrease the feed conversion rate and cause a variety of diseases of pig resulting in great economic losses in pig industry. The main measure to prevent and control the disease is immunization with high-quality vaccine. At present, vaccines against Mycoplasma hyopneumoniae infection is mainly divided into two types, inactivated vaccine and live vaccine. The inactivated vaccine generally is administrated by intramuscular immunization with simple operation, but the present commercially available inactivated vaccines are mainly imported products with limited protection ratios and high prices, while most domestic inactivated vaccines are water-in-oil formulations with poor security. The efficacy of the domestically developed live attenuated vaccine is better and the cost is relatively lower. However, the present live vaccine needs to be inoculated intrathoracicly, which greatly limits its promotion.Aim:The present study aimed at developing high-quality adjuvants for Mycoplasma hyopneumoniae vaccines to enhance the vaccine efficacy and reduce the toxic and side effects. Different adjuvants were applied to the inactivated vaccine and live vaccine. The study would greatly help the subsequent development of the new vaccines against Mycoplasma hyopneumoniae.Methods:Study on adjuvants of Mycoplasma hyopneumoniae inactivated vaccine focused on developing adjuvants using water as the continuous phase which would be safer than the water in oil adjuvant system. Oil-in-water emulsion and aqueous high-molecular polymer were used as the basic system. Different adjuvant components, including levamisole, astragalus polysaccharide, ISCOM-matirx, thymosin, CpG-ODN or sCpG-ODN, were added to form different adjuvant formulations. In addition to these adjuvants, another three commercial adjuvants(GEL01ST, ISA201and ISA11R) were also evaluated in this study. Mycoplasma hyopneumoniae inactivated vaccines using different adjuvants were prepared and immunized mice. Specific lymphocyte proliferation and serum antibody IgG against Mycoplasma hyopneumoniae were detected to compare the effects of different adjuvants.Study on adjuvants of Mycoplasma hyopneumoniae live vaccine focused on developing live vaccine acceptable adjuvant to enhance the immunogenicity of the present vaccine and make the intramuscular inoculation feasible. Oil-in-water emulsion and aqueous high-molecular polymer were used as the basic system. Different adjuvant components, including levamisole, astragalus polysaccharide or ISCOM-matirx, were added to form different adjuvant formulations. In addition to these adjuvants, GEL01ST was also evaluated in this study. Mycoplasma hyopneumoniae live vaccines using different adjuvants were prepared and immunized mice. Specific lymphocyte proliferation and serum antibody IgG against Mycoplasma hyopneumoniae were detected to compare the effects of different adjuvants.Moreover, this research alsostudy the stability of the adjuvant.Results:In the study of the inactivated vaccine, the results indicated that animals of all the adjuvant groups showed more significant immune responses compared with those of the control group. The carbomer-ISCOM-matrix combined adjuvant provided the greatest enhancement on both lymphocyte proliferation response and antibody production, followed by the carbomer-levamisole combined adjuvant and the GEL01ST adjuvant. The carbomer-thymosin combined adjuvant only enhanced the antibody level while the cellular immune response showed no change. In the study of the live vaccine, the ISCOM-matrix adjuvant provided the greatest enhancement on both lymphocyte proliferation response and antibody production, followed by the oil-in-water-levamisole combined adjuvant. The carbomer-levamisole combined high-dose adjuvant and carbomer-levamisole-astragalus polysaccharide combined adjuvant only enhanced the cellular immune response while the antibody level showed no change. The result of the stability study indicated that the prepared oil-in-water system adjuvant showed good stability. Among the different carbomer types, carbomer971P and974P are suitable for developing into adjuvants of the intramuscular injected live vaccineConclusion:In conclusion, the carbomer-ISCOM-matrix combined adjuvant, the carbomer-levamisole combined adjuvant and the GEL01ST adjuvant have the potential to be developed into adjuvants for the inactivated Mycoplasma hyopneumoniae vaccine. While the ISCOM-matrix adjuvant and the oil-in-water-levamisole combined adjuvant have the potential to be developed into adjuvants of the Mycoplasma hyopneumoniae live vaccine.