Ultrasensitive enzyme-linked immunosorbent assay for the detection of MPT64 secretory antigen to evaluate Mycobacterium tuberculosis viability in sputum

Abstract

This study examined Mycobacterium tuberculosis (MTB)-secreted MPT64 as a surrogate of bacterial viability for the diagnosis of active pulmonary TB (PTB) and for follow-up treatment. Methods: In this proof-of-concept prospective study, 50 PTB patients in the Tokyo metropolitan region, between 2017 and 2018, were consecutively included and 30 healthy individuals were also included. Each PTB patient submitted sputum on days 0, 14 and 28 for diagnosis and follow-up, and each healthy individual submitted one sputum sample. The following were performed: smear microscopy, Xpert MTB/RIF, MGIT and solid culture, and MPT64 detection on the sputum samples. Ultrasensitive ELISA (usELISA) was used to detect MPT64. The receiver operating characteristic analyses for diagnosis and follow-up revealed the optimal cut-off value of MPT64 absorbance for detecting culture positivity at multiple intervals. Results: The sensitivity of MPT64 for diagnosing PTB was 88.0% (95% CI 75.7-95.5) and the specificity was 96.7% (95% CI 82.8-99.9). The specificity of MPT64 for predicting negative culture results on day 14 was 89.5% (95% CI 66.9-98.7). The sensitivity of MPT64 for predicting positive culture results on day 28 was 81.0% (95% CI 58.1-94.6). Conclusions: This study revealed that MPT64 is useful for diagnosing active PTB in patients and predicting treatment efficacy at follow-up.

Neisseria gonorrhoeae Multivalent Maxibody with a Broad Spectrum of Strain Specificity and Sensitivity for Gonorrhea Diagnosis

“…The increased specificity and affinity of the antibody for its antigen is a desirable feature of reagents in immunological method-based POCTs. Recently, the use of an antibody tagged with alkaline phosphatase in conjunction with thionicotinamide-adenine dinucleotide (thio-NAD) for developing a sensitive immunoassay has been reported for the diagnosis of mycobacterium tuberculosis [52]. The multivalent maxibody platform, scFv-Fc-scFv, represents an excellent option for diagnosing gonorrheal infections.…”

A novel, rapid (within hours) culture-free diagnostic method for detecting live Mycobacterium tuberculosis with high sensitivity

“…Besides the similar performance of the culture-free ultrasensitive ELISA method and Xpert molecular tests, the culture-free ultrasensitive ELISA test is useful for monitoring the treatment response because this method detects only live bacilli [58] . When tuberculosis cases are under effective drug therapy, the culture-free ultrasensitive ELISA test may reveal negative results, whereas the molecular method might detect DNA from dead bacilli.…”

“…That is, the effect of blood in specimens on the tests should be excluded in our test. The other is that the examination of drug effectiveness should be promoted more [58] . The studies according to a new design of drug monitoring for patients will be achieved.…”

Anaphylatoxins orchestrate Th17 response via interactions between CD16+ monocytes and pleural mesothelial cells in tuberculous pleural effusion

“…antigen during the entire research process because Mpt64 is only secreted from live bacilli, and studies have shown that Mpt64 can be used as a substitute for bacterial viability to diagnose patients with active tuberculosis [47,48]. We want to simulate the sustained release of proteins from living bacilli by stimulating stromal cells and immune cells to secrete cytokines and upregulate monocyte costimulatory molecules to affect CD4 + T cells.…”