Effects of Mycobacterium vaccae vaccine in a mouse model of tuberculosis: protective action and differentially expressed genes

Background:Tuberculosis is a leading cause of death worldwide.BCG is an effective vaccine,but not widely used in many parts of the world due to a variety of issues.Mycobacterium vaccae(M.vaccae)is another vaccine used in human subjects to prevent tuberculosis.In the current study,we investigated the potential mechanisms of M.vaccae vaccination by determining differentially expressed genes in mice infected with M.tuberculosis before and after M.vaccae vaccination.Methods:Three days after exposure to M.tuberculosis H37 Rv strain(5×10~5 CFU),adult BALB/c mice randomly received either M.vaccae vaccine(22.5μg)or vehicle via intramuscular injection(n=8).Booster immunization was conducted 14 and 28 days after the primary immunization.Differentially expressed genes were identified by microarray followed by standard bioinformatics analysis.Results:M.vaccae vaccination provided protection against M.tuberculosis infection(most prominent in the lungs).We identified 2,326 upregulated and 2,221 downregulated genes in vaccinated mice.These changes could be mapped to a total of 123 signaling pathways(68 upregulated and 55 downregulated).Further analysis pinpointed to the MyD88-dependent TLR signaling pathway and PI3 K-Akt signaling pathway as most likely to be functional.Conclusions:M.vaccae vaccine provided good protection in mice against M.tuberculosis infection,via a highly complex set of molecular changes.Our findings may provide clue to guide development of more effective vaccine against tuberculosis.

Antitubercular activity of the semi-polar extractives of Uvaria rufa

Objective:To investigate the inhibitory activity of the chloroform extract,petroleum ether and chloroform sub-extracts,lead-acetate treated chloroform extract,fractions and secondary metabolites of Uvaria rufa(U.rufa) against Mycobacterium tuberculosis(M.tuberculosis) H_(37)Rv. Methods:The antituberculosis susceptibility assay was earried out using the colorimetric Microplate Alamar blue assay(MABA).In addition,the cytotoxicity of the most active fraction was evaluated using the VERO cell toxicity assay.Results:The in vitro inhibitory activity against M.tuberculosis H_(37)Rv increased as purification progressed to fractionation(MIC up to 23μg/mL). The chloroform extract and its sub-extracts showed moderate toxicity while the most active fraction from chloroform sub-extract exhibited no cytotoxicity against VERO cells.Meanwhile, the lead acetate-treated crude chloroform extract and its fractions showed complete inhibitions (100%) with MIC values up to 8μg/mL.Phylochemical screening of the most active fraction showed,in general,the presence of terpenoids,steroids and phenolic compounds.Evaluation of the antimycobacterial activity of known secondary metabolites isolated showed no promising inhibitory activity against the test organism.Conclusions:The present results demonstrate the potential of U.rufa as a phytomedicinal source of compounds that may exhibit promising antituberculosis activity.In addition,elimination of polar pigments revealed enhanced inhibition against M.tuberculosis H_(37)Rv.While several compounds known for this plant did not show antimycobacterial activity,the obtained results are considered sufficient reason for further study to isolate the metabolites from U.rufa responsible for the antitubercular activity.

Mannose-binding lectin 2 gene polymorphisms and their association with tuberculosis in a Chinese population

Background:Immune-and inflammation-related genes(IIRGs)play an important role in the pathogenesis of tuberculosis(TB).However,the relationship between IIRG polymorphisms and TB risk remains unknown.In this study,the gene polymorphisms and their association with tuberculosis were determined in a Chinese population.Methods:We performed a case-control study involving 1016 patients with TB and 507 healthy controls of Han Chinese origin.Sixty-four single-nucleotide polymorphisms(SNPs)belonging to 18 IIRGs were genotyped by the PCR-MassArray assay,and the obtained data was analyzed withχ2-test,Bonferroni correction,and unconditional logistic regression analysis.Results:We observed significant differences in the allele frequency of LTA rs2229094*C(P=0.015),MBL2 rs2099902*C(P=0.001),MBL2 rs930507*G(P=0.004),MBL2 rs10824793*G(P=0.004),and IL12RB1 rs2305740*G(P=0.040)between the TB and healthy groups.Increased TB risk was identified in the rs930507 G/G genotype(Padjusted=0.027)under a codominant genetic model as well as in the rs2099902(C/T+C/C)vs T/T genotype(Padjusted=0.020),rs930507(C/G+G/G)vs C/C genotype(Padjusted=0.027),and rs10824793(G/A+G/G)vs A/A genotype(Padjusted=0.017)under a dominant genetic model after Bonferroni correction in the analysis of the overall TB group rather than the TB subgroups.Furthermore,the rs10824793_rs7916582*GT and rs10824793_rs7916582*GC haplotypes were significantly associated with increased TB risk(P=0.001,odds ratio[OR]=1.421,95%confidence interval[CI]:1.152-1.753;and P=0.018,OR=1.364,95%CI:1.055-1.765,respectively).Moreover,the rs10824793_rs7916582*AT/AT or rs10824793_rs7916582*GT/GT diplotype showed a protective(P=0.003,OR=0.530,95%CI:0.349-0.805)or harmful(P=0.009,OR=1.396,95%CI:1.087-1.793)effect against the development of TB.Conclusions:This study indicated that MBL2 polymorphisms,haplotypes,and diplotypes were associated with TB susceptibility in the Han Chinese population.Additionally,larger sample size studies are needed to further confirm these findings in the future.