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Mycobacterium tuberculosis Zinc Metalloprotease-1 Elicits Tuberculosis-Specific Humoral Immune Response Independent of Mycobacterial Load in Pulmonary and Extra-Pulmonary Tuberculosis Patients.

Vemula MH, Ganji R, Sivangala R, Jakkala K, Gaddam S, Penmetsa S, Banerjee S - Front Microbiol (2016)

Bottom Line: The anti-Zmp1 titers were significantly higher in TB patients (n = 121) as against healthy control (n = 62), household contacts (n = 89) and non-specific infection controls (n = 23).A significant observation of the study is the presence of equally high titers of anti-Zmp1 antibodies in a range of patients with high bacilli load (sputum bacilli load of 300+ per mL) to paucibacillary smear-negative pulmonary tuberculosis (PTB) cases.This clearly indicated the potential of Zmp1 to evoke an effective humoral response independent of mycobacterial load.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry, School of Life Sciences, University of Hyderabad Hyderabad, India.

ABSTRACT
Conventionally, facultative intracellular pathogen, Mycobacterium tuberculosis, the tuberculosis (TB) causing bacilli in human is cleared by cell-mediated immunity (CMI) with CD4(+) T cells playing instrumental role in protective immunity, while antibody-mediated immunity (AMI) is considered non-protective. This longstanding convention has been challenged with recent evidences of increased susceptibility of hosts with compromised AMI and monoclonal antibodies conferring passive protection against TB and other intracellular pathogens. Therefore, novel approaches toward vaccine development include strategies aiming at induction of humoral response along with CMI. This necessitates the identification of mycobacterial proteins with properties of immunomodulation and strong immunogenicity. In this study, we determined the immunogenic potential of M. tuberculosis Zinc metalloprotease-1 (Zmp1), a secretory protein essential for intracellular survival and pathogenesis of M. tuberculosis. We observed that Zmp1 was secreted by in vitro grown M. tuberculosis under granuloma-like stress conditions (acidic, oxidative, iron deficiency, and nutrient deprivation) and generated Th2 cytokine microenvironment upon exogenous treatment of peripheral blood mononulear cells PBMCs with recombinant Zmp1 (rZmp1). This was supported by recording specific and robust humoral response in TB patients in a cohort of 295. The anti-Zmp1 titers were significantly higher in TB patients (n = 121) as against healthy control (n = 62), household contacts (n = 89) and non-specific infection controls (n = 23). A significant observation of the study is the presence of equally high titers of anti-Zmp1 antibodies in a range of patients with high bacilli load (sputum bacilli load of 300+ per mL) to paucibacillary smear-negative pulmonary tuberculosis (PTB) cases. This clearly indicated the potential of Zmp1 to evoke an effective humoral response independent of mycobacterial load. Such mycobacterial proteins can be explored as antigen candidates for prime-boost vaccination strategies or extrapolated as markers for disease detection and progression.

No MeSH data available.


Related in: MedlinePlus

rRv0198c ELISA detected all active TB cases with high specificity and sensitivity.(A) Box plots representing titers of anti-Rv0198c antibody titers as indicated by values at Absorbance 450 nm in Healthy, extra-pulmonary TB (EPTB), EPTB patient contacts (Household contacts of EPTB patients). (B) Box plots representing titers of anti-Rv0198c antibody titers as indicated by values at Absorbance 450 nm in Healthy, pulmonary TB (PTB), PTB patient contacts (Household contacts of PTB patients). ∗The differences in Abs450 values for PTB vs. Healthy; PTB vs. PTB Household contacts; EPTB vs. Healthy; EPTB vs. EPTB Household contacts were highly significant and a p-value of <0.001 was observed in all the cases. Statistical analyses were done using one-way ANOVA on ranks was performed with Dunn’s method for pair-wise comparison method.
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Figure 5: rRv0198c ELISA detected all active TB cases with high specificity and sensitivity.(A) Box plots representing titers of anti-Rv0198c antibody titers as indicated by values at Absorbance 450 nm in Healthy, extra-pulmonary TB (EPTB), EPTB patient contacts (Household contacts of EPTB patients). (B) Box plots representing titers of anti-Rv0198c antibody titers as indicated by values at Absorbance 450 nm in Healthy, pulmonary TB (PTB), PTB patient contacts (Household contacts of PTB patients). ∗The differences in Abs450 values for PTB vs. Healthy; PTB vs. PTB Household contacts; EPTB vs. Healthy; EPTB vs. EPTB Household contacts were highly significant and a p-value of <0.001 was observed in all the cases. Statistical analyses were done using one-way ANOVA on ranks was performed with Dunn’s method for pair-wise comparison method.

Mentions: Some of the reports have indicated antibodies against specific M. tuberculosis antigens in the sera of clinically healthy, latently infected Health-care workers (Reis et al., 2009). With the anti-Zmp1 antibodies detected in active EPTB and even in active paucibacillary PTB cases (Table 1), we wanted to check if anti-Zmp1 titers were also detectable in the respective household contacts. These household contacts had stayed with active patients for at the least seven consecutive days during the 3 months prior to the diagnosis of TB. They were expected to be exposed to M. tuberculosis though it is reported that EPTB patients, specifically those with tissue TB, are unlikely to transmit the bacilli. Most of these clinically asymptomatic contacts were tested positive for Mantoux’s test (Out of 89 household contacts, 60 subjects were Mantoux positive with diameter of Induration >15 mm) and hence may represent possible cases of latent TB. To evaluate that, ELISA readings of EPTB (n = 55) and their respective household contacts (n = 55) and PTB (n = 66) and their household contacts (n = 34) were plotted (Figures 5A,B). It was observed that compared to EPTB patient contacts (Median: 0.663; IQR: 0.524–0.808) or PTB patient contacts (Median: 0.570; IQR: 0.387–0.630), titers of anti-Zmp1 antibody were distinctly high in EPTB patients (Median: 1.421; IQR: 0.979–2.259; p < 0.001) or PTB patients (Median: 1.257; IQR: 0.956–1.8; p < 0.001), respectively (Figures 5A,B), suggesting that Zmp1 humoral response is restricted to active infection cases as against asymptomatic household contacts including Mantoux positive cases under the category which may be possible latent subjects.


Mycobacterium tuberculosis Zinc Metalloprotease-1 Elicits Tuberculosis-Specific Humoral Immune Response Independent of Mycobacterial Load in Pulmonary and Extra-Pulmonary Tuberculosis Patients.

Vemula MH, Ganji R, Sivangala R, Jakkala K, Gaddam S, Penmetsa S, Banerjee S - Front Microbiol (2016)

rRv0198c ELISA detected all active TB cases with high specificity and sensitivity.(A) Box plots representing titers of anti-Rv0198c antibody titers as indicated by values at Absorbance 450 nm in Healthy, extra-pulmonary TB (EPTB), EPTB patient contacts (Household contacts of EPTB patients). (B) Box plots representing titers of anti-Rv0198c antibody titers as indicated by values at Absorbance 450 nm in Healthy, pulmonary TB (PTB), PTB patient contacts (Household contacts of PTB patients). ∗The differences in Abs450 values for PTB vs. Healthy; PTB vs. PTB Household contacts; EPTB vs. Healthy; EPTB vs. EPTB Household contacts were highly significant and a p-value of <0.001 was observed in all the cases. Statistical analyses were done using one-way ANOVA on ranks was performed with Dunn’s method for pair-wise comparison method.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4814508&req=5

Figure 5: rRv0198c ELISA detected all active TB cases with high specificity and sensitivity.(A) Box plots representing titers of anti-Rv0198c antibody titers as indicated by values at Absorbance 450 nm in Healthy, extra-pulmonary TB (EPTB), EPTB patient contacts (Household contacts of EPTB patients). (B) Box plots representing titers of anti-Rv0198c antibody titers as indicated by values at Absorbance 450 nm in Healthy, pulmonary TB (PTB), PTB patient contacts (Household contacts of PTB patients). ∗The differences in Abs450 values for PTB vs. Healthy; PTB vs. PTB Household contacts; EPTB vs. Healthy; EPTB vs. EPTB Household contacts were highly significant and a p-value of <0.001 was observed in all the cases. Statistical analyses were done using one-way ANOVA on ranks was performed with Dunn’s method for pair-wise comparison method.
Mentions: Some of the reports have indicated antibodies against specific M. tuberculosis antigens in the sera of clinically healthy, latently infected Health-care workers (Reis et al., 2009). With the anti-Zmp1 antibodies detected in active EPTB and even in active paucibacillary PTB cases (Table 1), we wanted to check if anti-Zmp1 titers were also detectable in the respective household contacts. These household contacts had stayed with active patients for at the least seven consecutive days during the 3 months prior to the diagnosis of TB. They were expected to be exposed to M. tuberculosis though it is reported that EPTB patients, specifically those with tissue TB, are unlikely to transmit the bacilli. Most of these clinically asymptomatic contacts were tested positive for Mantoux’s test (Out of 89 household contacts, 60 subjects were Mantoux positive with diameter of Induration >15 mm) and hence may represent possible cases of latent TB. To evaluate that, ELISA readings of EPTB (n = 55) and their respective household contacts (n = 55) and PTB (n = 66) and their household contacts (n = 34) were plotted (Figures 5A,B). It was observed that compared to EPTB patient contacts (Median: 0.663; IQR: 0.524–0.808) or PTB patient contacts (Median: 0.570; IQR: 0.387–0.630), titers of anti-Zmp1 antibody were distinctly high in EPTB patients (Median: 1.421; IQR: 0.979–2.259; p < 0.001) or PTB patients (Median: 1.257; IQR: 0.956–1.8; p < 0.001), respectively (Figures 5A,B), suggesting that Zmp1 humoral response is restricted to active infection cases as against asymptomatic household contacts including Mantoux positive cases under the category which may be possible latent subjects.

Bottom Line: The anti-Zmp1 titers were significantly higher in TB patients (n = 121) as against healthy control (n = 62), household contacts (n = 89) and non-specific infection controls (n = 23).A significant observation of the study is the presence of equally high titers of anti-Zmp1 antibodies in a range of patients with high bacilli load (sputum bacilli load of 300+ per mL) to paucibacillary smear-negative pulmonary tuberculosis (PTB) cases.This clearly indicated the potential of Zmp1 to evoke an effective humoral response independent of mycobacterial load.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry, School of Life Sciences, University of Hyderabad Hyderabad, India.

ABSTRACT
Conventionally, facultative intracellular pathogen, Mycobacterium tuberculosis, the tuberculosis (TB) causing bacilli in human is cleared by cell-mediated immunity (CMI) with CD4(+) T cells playing instrumental role in protective immunity, while antibody-mediated immunity (AMI) is considered non-protective. This longstanding convention has been challenged with recent evidences of increased susceptibility of hosts with compromised AMI and monoclonal antibodies conferring passive protection against TB and other intracellular pathogens. Therefore, novel approaches toward vaccine development include strategies aiming at induction of humoral response along with CMI. This necessitates the identification of mycobacterial proteins with properties of immunomodulation and strong immunogenicity. In this study, we determined the immunogenic potential of M. tuberculosis Zinc metalloprotease-1 (Zmp1), a secretory protein essential for intracellular survival and pathogenesis of M. tuberculosis. We observed that Zmp1 was secreted by in vitro grown M. tuberculosis under granuloma-like stress conditions (acidic, oxidative, iron deficiency, and nutrient deprivation) and generated Th2 cytokine microenvironment upon exogenous treatment of peripheral blood mononulear cells PBMCs with recombinant Zmp1 (rZmp1). This was supported by recording specific and robust humoral response in TB patients in a cohort of 295. The anti-Zmp1 titers were significantly higher in TB patients (n = 121) as against healthy control (n = 62), household contacts (n = 89) and non-specific infection controls (n = 23). A significant observation of the study is the presence of equally high titers of anti-Zmp1 antibodies in a range of patients with high bacilli load (sputum bacilli load of 300+ per mL) to paucibacillary smear-negative pulmonary tuberculosis (PTB) cases. This clearly indicated the potential of Zmp1 to evoke an effective humoral response independent of mycobacterial load. Such mycobacterial proteins can be explored as antigen candidates for prime-boost vaccination strategies or extrapolated as markers for disease detection and progression.

No MeSH data available.


Related in: MedlinePlus