ABSTRACT
Tuberculosis (TB) is a contagious disease that has been responsible for the death of one billion people in the last 200 years. Until now, the only vaccine approved for the prevention of TB is Bacillus Calmette-Guérin (BCG), which is prepared by attenuating Mycobacterium bovis. However, one of the limitations of BCG is that its preventive effect against pulmonary TB varies from person to person. Therefore, there arises a need for a new TB vaccine to replace or supplement BCG. In this review, we have summarized the findings of current clinical trials on preventive and therapeutic TB vaccine candidates. In addition, we have discussed a novel vaccination approach using the cell-based vaccine presenting early secretory antigenic target-6 (ESAT-6), which is a potent immunogenic antigen. The role of ESAT-6 in hosts has also been described.
Subject(s)
Humans , Bacillus , Mycobacterium bovis , Tuberculosis , Vaccination , VaccinesABSTRACT
Objective To establish a near‐infrared fluorescent dye‐immunomagnetic beads coupling method for quantitative de‐tection of Mycobacterium tuberculosis early secretory antigenic target‐6(ESAT‐6) .Methods Near‐infrared fluorescent dye ,dylight 800 ,was used to mark ESTA‐6‐targeting monoclonal antibodies ,and the surface of nano‐magnetic beads were coated with ESAT‐6‐targeting polyclonal antibodies .Double antibody sandwich method was used for magnetic separation of conjugates and dissociants . Portable high‐sensitivity and low‐noise excitation fluorescence detector was used to detect the intensity of magnetic combination ,so as to test the ESAT‐6 content in test samples .Results The detecting linear range of this method was 2 .4-750 .0 ng/mL ,and the minimum detection limit was 0 .48 ng/mL .The recovery rate was 96% at a concentration of 10 ng/mL ,and at a concentration of 50 ng/mL the recovery rate was 95% .The between‐run coefficient of variation(CV)value was 5 .8% ,and the within‐run CV value was 4 .3% .The specificity and sensitivity of this method for detecting ESAT‐6 in clinical pleural effusion samples were 80% and 95% , respectively .Conclusion This method might have wide linear range ,high sensitivity and good stability in the detection of ESAT‐6 .
ABSTRACT
ObjectiveTo evaluate the value of early secretory antigenic target 6 (ESAT-6) in monocytes of cerebrospinal fluid (CSF) in the early diagnosis and judgment of the tuberculous meningitis (TBM). MethodsForty cases with TBM (TBM group) and 40 patients with other meningitis patients (control group,9 cases with purulent meningitis,24 cases with viral meningitis,3 cases with cryptococcal meningitis,3 cases with cerebral cysticercosis, 1 case with neurosyphyilis) were involved in this study.Conventional examination of CSF was inspected after admission, and the ESAT-6 in monocytes of CSF was detected by immunocytochemical stain. ResultsThe positive rate of ESAT-6 was 24％ in TBM group and 0 in control group (P ＜ 0.01 ). In ROC curve, if the rate of ESAT-6 ≥8.5％ judged as positive, and ＜ 8.5％ judged as negative, 35 patients of TBM group and 4 patients of control group were ESAT-6 positive. The sensitivity of the ESAT-6 in the diagnosis of TBM was 87.5％, and the specificity of TBM was 90.0％. Thirty patients in TBM group were not given anti-tuberculosis drug treatment, and the positive rate of ESAT-6 was 93.3％ (28/30) before treatment, and was 46.7％ (14/30) after treatment of 2 weeks (P =0.000).ConclusionsESAT-6 in monocytes of CSF detected by immunocytochemical stain has higher sensitivity and specificity in the diagnosis of TBM in early stage. Observing the positive rate of ESAT-6 dynamicly has practical value in judgment the severity of TBM.