Differential Roles of Toll-like Receptor (TLR) 2 and 4 between PPD- and 38-kDa-induced Proinflammatory Cytokine Productions in Human Monocytes

In this study, we investigated the role of toll-like receptor (TLR) and mitogen-activated protein kinase (MAPK) pathways involved in the tumor necrosis factor (TNF)-alpha and interleukin (IL)-6 expression after stimulation with purified protein derivatives (PPD) or native 38-kDa protein antigen (Ag) of Mycobacterium tuberculosis H37Rv in human primary monocytes. Both PPD and 38-kDa Ag significantly induced TNF-alpha and IL-6 in human primary monocytes. MAPK [extracellular signal-regulated kinase (ERK) 1/2 and p38] are rapidly phosphorylated in human monocytes stimulated with the PPD or 38-kDa Ag. Both p38 and ERK 1/2 activation are essential for PPD- or 38-kDa-induced TNF-alpha and IL-6 production. The inhibition of TLR2 and TLR4 by specific antibodies significantly abrogated the 38-kDa-induced secretion of TNF-alpha and IL-6, whereas blockade of TLR2, but not TLR4, was responsible for the PPD-induced TNF-alpha and IL-6 production in human monocytes. Collectively, these data suggest that the PPD and 38-kDa Ag differentially interact with TLR2 and TLR4, which in turn mediate an essential role for the early inflammatory immune responses during human tuberculosis.

Evaluation of the Clinical Usefulness of the Xeniss Rapid TB kit for the Diagnosis of Tuberculosis / 결핵

BACKGROUND: The rapid diagnostic tests for tuberculosis are needed to facilitate early treatment of tuberculosis and prevention of Mycobacterium tuberculosis transmission. The Xeniss Rapid TB kit is a rapid, card-based immunochromatographic test for the detection of antibodies directed against M. tuberculosis antigens including antigen 5(38-kDa antigen). The objective of this study was to evaluate the performance of the Xeniss Rapid TB kit for the diagnosis of active tuberculosis with serums from patients, asymptomatic healthy and close contact controls. METHOD: 188 patients with active tuberculosis were tested; 177 with pulmonary tuberculosis(18 with combined pleurisy), and 11 with extrapulmonary tuberculosis. The control groups were composed of 82 close contacts and 57 healthy adults. Study subjects were drawn from one national tuberculosis hospital for patients and close contacts, and another private hospital for healthy adults in Masan city, Korea. The Xeniss Rapid TB kit(Xeniss Life Science Co., Ltd., Seoul, Korea) was evaluated by using serum samples according to the instructions of the manufacturer by an investigator masked to the clinical and microbiological status of the study subjects. RESULTS: The diagnostic sensitivity of the Xeniss Rapid TB kit was 73.9% in patients and specificities were 73.2% and 93.0% in close contact and healthy adults respectively. The positive predictive value in patients was 84.2% and the negative predictive value in controls was 85.8%. CONCLUSIONS: This study shows that the Xeniss Rapid TB test is a simple and fast method to diagnose active TB. The results of the sensitivity and specificites suggest that serodiagnosis using this point of care testing(POCT) device would be valuable and advantageous for screening tuberculosis in the clinical field.

Purification and Partial Characterization of the 38 kDa Glycolipoprotein Antigen from the Culture Filtrate of Mycobacterium tuberculosis H37Rv

Mycobacterium tuberculosis infected macrophages can become ineffective at activating CD4+ T cells through presentation of peptide antigens by MHC class II, possibly contributing to the ability of M tuberculosis to persist despite the presence of an intact immune system. Presentation of lipid antigens may help to overcome this problem. CD1 represents the key component of an MHC independent pathway for presentation nonpeptide lipid antigens to T cells. The 38 kDa glycolipoprotein antigen of M. tuberculosis is actively secreted. The antigen induces strong antibody and T-cell responses and provided partial protection against M. tuberculosis infection in mice when it is administered either entrapped in biodegradable microparticles or in the form of a DNA vaccine. But an selective anergy to stimulation with peptide of the 38 kDa was observed in the majority of tuberculosis patients. An 38 kDa antigen has been isolated by affinity chromatography using a monoclonal antibody. This antigen contains some immunosuppressive cell wall associated antigens such as lipoarabinomannan. Therefore, we purified the 38 kDa glycolipoprotein from the culture filtrate of M tuberculosis H37Rv by ammonium sulfate precipitation (55~80%), hydroxylapatite and DEAE-Sephacel column. The purified antigen showed three major bands on isoelectric focusing gel, and two-dimensional electrophoresis (2-DE) analysis of this antigen revealed five distinct spots of the 38 kDa molecular mass. One of five spots had a N-terminal sequence identical to that of the 38 kDa glycolipoprotein (pstS-1). Other protein spots could not determine sequences. An antiserum against the recombinant 38 kDa antigen of M tuberculosis reacted strongly with the purified the 38 kDa antigen.

Evaluating the Usefulness of the ICT Tuberculosis Test Kit for the Diagnosis of Tuberculosis / 결핵

BACKGROUND: Early diagnosis of tuberculosis is critical, especially in Korea, an area where tuberculosis is endemic. Because antibody responses to some membrane proteins of Mycobacterium tuberculosis are not comparable, and the policy of BCG vaccination and the prevalence of tuberculosis are different from country to country, the usefulness of the serological diagnostic tests is questionable in Korea, even though they have been confirmed to be useful in other countries. In the specific context of Korea, we tried to evaluate the validity of the ICT Tuberculosis Test (ICT), a membrane-based antibody kit that purports to detect the 5 M. tuberculosis complex-specific antigens including 38-kDa protein. METHOD: 68 patients with tuberculosis were tested: 37 had no history of previous tuberculosis, and 31 were reactivated cases. The control group comprised 77 subjects: 25 healthy adults, 35 hospital workers with frequent contact with tuberculosis patients, and 17 in-patients with non-tuberculous respiratory diseases. RESULTS: The diagnostic sensitivities of the ICT were 87% and 73% in patients with versus without previous history of tuberculosis, respectively. The sensitivities of smear-positive and smear-negative patient groups were 81% and 73%, respectively. Both of the two patients with extrapulmonary tuberculosis tested positive through the ICT. The specificities of the ICT were 88%, 94%, and 94% in healthy adults, hospital workers, and non-tuberculous patients, respectively, with an overall specificity of 92%. Conclusion: It is suggested that when combined with traditional techniques, the ICT is an useful tool for the diagnosis of pulmonary tuberculosis. The procedure is simple, easy to perform, rapid, and needs no equipment. It shows 73% sensitivity and 92% specificity for the diagnosis of tuberculosis.

Evaluating the Usefulness of the ICT Tuberculosis Test Kit for the Diagnosis of Tuberculosis / 결핵

BACKGROUND: Early diagnosis of tuberculosis is critical, especially in Korea, an area where tuberculosis is endemic. Because antibody responses to some membrane proteins of Mycobacterium tuberculosis are not comparable, and the policy of BCG vaccination and the prevalence of tuberculosis are different from country to country, the usefulness of the serological diagnostic tests is questionable in Korea, even though they have been confirmed to be useful in other countries. In the specific context of Korea, we tried to evaluate the validity of the ICT Tuberculosis Test (ICT), a membrane-based antibody kit that purports to detect the 5 M. tuberculosis complex-specific antigens including 38-kDa protein. METHOD: 68 patients with tuberculosis were tested: 37 had no history of previous tuberculosis, and 31 were reactivated cases. The control group comprised 77 subjects: 25 healthy adults, 35 hospital workers with frequent contact with tuberculosis patients, and 17 in-patients with non-tuberculous respiratory diseases. RESULTS: The diagnostic sensitivities of the ICT were 87% and 73% in patients with versus without previous history of tuberculosis, respectively. The sensitivities of smear-positive and smear-negative patient groups were 81% and 73%, respectively. Both of the two patients with extrapulmonary tuberculosis tested positive through the ICT. The specificities of the ICT were 88%, 94%, and 94% in healthy adults, hospital workers, and non-tuberculous patients, respectively, with an overall specificity of 92%. Conclusion: It is suggested that when combined with traditional techniques, the ICT is an useful tool for the diagnosis of pulmonary tuberculosis. The procedure is simple, easy to perform, rapid, and needs no equipment. It shows 73% sensitivity and 92% specificity for the diagnosis of tuberculosis.

The Usefulness of Serologic Diagnosis for Tuberculosis with Two Rapid Immunochromatographic Assay Devices / 결핵

BACKGROUND: Many diagnostic tests have developed to diagnose tuberculosis and other mycobacterial diseases but the diagnosis of tuberculosis relies largely on radiological findings and acid-fast staining of sputum and/or culture. Recently, new serologic diagnostic methods, which are safe and easy to use have been introduced into Korea. In this study, the usefulness of serologic diagnosis for tuberculosis and the disease pattern induced variation of the test were evaluated. METHODS: Serological assay was performed upon 108 patients with two test kits, the ICT tuberculosis and the BioSign(TM) TB, which are based upon a rapid immunochromatographic assay technique, capable of being interpreted within 15 minutes. The case groups consisted of 61 patients with active pulmonary tuberculosis(36 patients), extrapulmonary tuberculosis(3 patients), or both (22 patients). Control groups consisted of 47 patients with inactive old pulmonary tuberculosis (17 patients), nontuberculous pulmonary disease(16 patients) and nonpulmonary cardiac disease(14 patients). RESULTS: The diagnostic sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the ICT tuberculosis were 64.3%, 91.5%, 90.0% and 68.3% respectively. The diagnostic sensitivity, specificity, PPV and NPV of the BioSign(TM) TB were 76.5%, 95.3%, 94.1% and 78.8% respectively. Differences in sensitivity were not significant between patients with previous history of tuberculosis or patients without prior history of tuberculosis. The ICT tuberculosis test showed higher sensitivity in pulmonary tuberculosis patients (76.5%) than extrapulmonary tuberculosis patients (33.3%). There was no difference in sensitivity between patients with or without cavitary lesion by chest X-ray. CONCLUSION: Considering high specificity and PPV, serologic diagnosis using a rapid immunochromatographic assay device is another helpful diagnostic method in the diagnosis of tuberculosis, when combined with previous diagnostic methods such as chest X-ray, microbiologic study but it has limitation in terms of confirming the diagnosis for tuberculosis as the only diagnostic method because of relatively low sensitivity and NPV.

Diagnostic Significance of the Serologic Test Using Antigen of Mycobacterium Tuberculosis for Antibody Detection by ELISA / 결핵

BACKGROUND: Diagnosis by direct microscopy and/or by culture of the Mycobacterium tuberculosis from body fluids or biopsy specimens is "Gold standard". However, the sensitivity of direct microscopy after Ziehl-Neelsen staining is relatively low and culture of mycobacteria is time consuming. Detection of mycobacterial DNA in clinical samples by the polymerase chain reaction is highly sensitive but laborious and expensive. Therefore, rapid, sensitive and readily applicable new tests need to be developed. So we had evaluated the clinical significance of serologic detection of antibody to 38 kDa antigen, which is known as the most specific to the M. tuberculosis complex, and culture filtrate antigen by ELISA in sputum AFB smear negative patients. METHOD: In this study, culture tests for acid fast bacilli with sputa or bronchial washing fluids of 183 consecutive patients who were negative of sputum AFB smear were performed. Simultaneously serum antibodies to 38 kDa antigen and unheated culture filtrate of M. tuberculosis were detected by an ELISA method. RESULTS: The optical densities of ELISA test with 38 kDa and culture filtrate antigen were significantly higher in active pulmonary tuberculosis cases than in non tuberculous pulmonary diseases (pO.05). In the smear-negative active pulmonary tuberculosis patients, the sensitivity of the ELISA using 38 kDa antigen and culture filtrate was 20.0% and 31.4%, respectively. The specificity was 95.3% and 93.9%, respectively. CONCLUSION: In active pulmonary tuberculosis but smear negative, the serologic detection of antibody to 38 kDa antigen and culture filtrate by ELISA cannot substitute traditional diagnostic tests and does not have clinically significant role to differenciate the patient with active pulmonary tuberculosis from other with non-tuberculous pulmonary diseases.