Research On Screening Serum Biomarkers Using Mycobacterium Tuberculosis Proteome Microarray

Mycobacterium tuberculosis(Mtb)has infected approximately one third of the world's population.Most individuals develop latent TB infection(LTBI),which is characterized by the balance state between Mtb infection and host.Individuals with LTBI have a 5%~10% chance of reactivation,ultimately progress to active TB in their lifetimes.Therefore,early detection,appropriate prevention and treatment of LTBI could reduce the risk of developing active TB,especially,treatment for LTBI with some high-risk factors.Currently,conventional LTBI diagnosis continues to rely on the Mantoux tuberculin skin test(TST)and interferon-? release assays(IGRAs),but they both have some limitations.In the first part of this article,we screened serum biomarkers at a system level using serum samples between latent TB infection(LTBI)and active TB patients by Mycobacterium tuberculosis(Mtb)proteome microarray.After bioinformatics analysis,the results showed that a large number of antigens that differently response to IgG or IgM antibodies were significantly higher in active TB patients than in LTBI subjects.To provide further validation,12 potential biomarkers were analyzed by enzyme-linked immunosorbent assay(ELISA)using 279 samples.Diagnostic efficiency was evaluated by creating receiver operating characteristic(ROC)curves.Among the biomarkers,Rv2031 c and Rv1408 showed general diagnostic efficiency between LTBI and active TB patients.Furthermore,we establish a regression model through bivariate logistic regression analysis,which has better diagnostic efficiency than any single antigens and the combination result of Rv2031 c,Rv1408 and Rv2421 c,with higher sensitivity and specificity of 88.04% and 96.77%,respectively.In summary,the regression model could potentially serve as a diagnostic index for discrimination between LTBI and active TB patients.Mycobacterium bovis bacillus Calmette Guerin(BCG)is the only available vaccine against TB recommended by WHO,with an estimated that more than three billion doses have been used since 1921.Although BCG have been used widely,there isn't have a definite method to evaluate the protective effect of BCG vaccination.Traditionally,BCG vaccination scar and the Mantoux tuberculin skin test(TST)were used,but these methods have some shortcomings.In addition,host immune protective mechanism against BCG vaccination is not yet completely elucidated,so there is little research on establishing a method to evaluate the protective effect of BCG.In the second part of this article,we screened serum biomarkers at a system level using serum samples between health control group and BCG vaccination group by Mycobacterium tuberculosis proteome microarray.The results showed that 142 or 91 antigens that differently response to IgG or IgM antibodies,respectively.We suggest that these antigens can induce stronger humoral immunity,and provide a basis data for better understanding protective immune mechanism of BCG.To provide further validation,6 potential biomarkers were analyzed by ELISA assay;we found that Rv2728 c,Rv2150c and Rv2716 showed higher level of IgG antibody in BCG vaccination group,they have better diagnostic efficiency through ROC analysis.Furthermore,we establish a regression model through bivariate logistic regression,which has better diagnostic efficiency than any single antigens,with higher sensitivity and specificity of 95.16% and 98.39%,respectively,this provide a basis on establishing a method to evaluate the protective effect of BCG.