| At present,the prevention and control of Tuberculosis(TB)is in a severe state.The emergence of Mycobacterium tuberculosis(Mtb)strains,which have drug resistance,is increasing the damage of Tuberculosis to humans,and now there is no once and for all method can relieve the threat of Tuberculosis.Meanwhile vaccination is the most effective intervention to control infectious diseases,it is necessary to speed up the pace of TB vaccine development.This study explored the efficacy of several subunit vaccines(Rv0199-Rv0394c-OmpA(RRO),Rv3802c-Ag85A-TB10.4(RAT),Rv2660c-Mtb32A-MPT51(RMM)).When compared different subunit vaccines,the immune enhancement effects of bacteria ghost and Incomplete Freund Adjuvant(IFA)on subunit vaccines were compared.In this study,nine target genes were divided into three groups and every group contained three genes.These groups were linked into the expression vector and the corresponding fusion proteins were obtained.Subsequently,the fusion proteins,combined with Incomplete Freund Adjuvant(IFA)or Salmonella Ghost,were injected into mice and the corresponding indexes were detected.The results showed that the group named protein RRO had a higher level of antibody titer in prime immunization.The proportion of CD4+ T lymphocytes of the RAT and RMM groups were lower than that of the RRO group and only after second immunization,this index became the same.The secretion of IL-4 of the RRO group was also higher than that of the other two groups after second immunization.The other indexes of protein RRO were not significantly different from the other two fusion proteins.Therefore,the immune response stimulated by RRO,as an antigen,was slightly stronger than that of the other two fusion proteins.For the comparison of efficacy of commercialized IFA and Salmonella Ghost as adjuvant,it was found that the antibody titer of the Ghost group was only lower than that of the IFA group in prime immunization and there was no significant difference between the two groups after second immunization.In the case of lymphocyte differentiation,the proportion of CD4+ T lymphocyte of different proteins’ Ghost group were lower or higher than that of IFA group in prime immunization,but after second immunization,this index became the same.In terms of safety,Ghost,as an adjuvant,is flat with IFA,and even better than IFA in some cases.Thus,the role of Salmonella Ghost as an adjuvant can be competitive to the commercialized DIFA.In conclusion,the fusion proteins(RRO,RAT and RMM)of Mycobacterium tuberculosis were successfully expressed and purified.These fusion proteins could stimulate the mice to produce a good immune response,and RRO was better than the other two fusion proteins.The evaluation of Salmonella Ghost showed that the Ghost had an adjuvant function for subunit vaccine. |
