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A Mycobacterium tuberculosis Dormancy Antigen Differentiates Latently Infected Bacillus Calmette-Guérin-vaccinated Individuals.

Peña D, Rovetta AI, Hernández Del Pino RE, Amiano NO, Pasquinelli V, Pellegrini JM, Tateosian NL, Rolandelli A, Gutierrez M, Musella RM, Palmero DJ, Gherardi MM, Iovanna J, Chuluyan HE, García VE - EBioMedicine (2015)

Bottom Line: LTBI subjects secreted significantly higher IFN-γ levels against Rv2626c than HD.Interestingly, whole blood stimulation with Rv2626c allowed the discrimination between active and latent infections, since TB patients did not secrete IFN-γ against Rv2626c, in contrast to CFP-10 + ESAT-6 stimulation that induced IFN-γ response from both LTBI and TB patients.ROC analysis confirmed that Rv2626c discriminated LTBI from HD and TB patients.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Química Biológica, Facultad de Ciencias Exactas y Naturales (IQUIBICEN), UBA (Universidad de Buenos Aires)-CONICET, Intendente Güiraldes 2160, Pabellón II, 4°piso, Ciudad Universitaria, C1428EGA Buenos Aires, Argentina ; Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, UBA, Intendente Güiraldes 2160, Pabellón II, 4°piso, Ciudad Universitaria, C1428EGA Buenos Aires, Argentina.

ABSTRACT
IFN-γ release assays (IGRAs) are better indicators of Mycobacterium tuberculosis infection than the tuberculin skin test (TST) in Bacillus Calmette-Guérin (BCG)-vaccinated populations. However, IGRAs do not discriminate active and latent infections (LTBI) and no gold standard for LTBI diagnosis is available. Thus, since improved tests to diagnose M. tuberculosis infection are required, we assessed the efficacy of several M. tuberculosis latency antigens. BCG-vaccinated healthy donors (HD) and tuberculosis (TB) patients were recruited. QuantiFERON-TB Gold In-Tube, TST and clinical data were used to differentiate LTBI. IFN-γ production against CFP-10, ESAT-6, Rv2624c, Rv2626c and Rv2628 antigens was tested in peripheral blood mononuclear cells. LTBI subjects secreted significantly higher IFN-γ levels against Rv2626c than HD. Additionally, Rv2626c peptide pools to which only LTBI responded were identified, and their cumulative IFN-γ response improved LTBI discrimination. Interestingly, whole blood stimulation with Rv2626c allowed the discrimination between active and latent infections, since TB patients did not secrete IFN-γ against Rv2626c, in contrast to CFP-10 + ESAT-6 stimulation that induced IFN-γ response from both LTBI and TB patients. ROC analysis confirmed that Rv2626c discriminated LTBI from HD and TB patients. Therefore, since only LTBI recognizes specific epitopes from Rv2626c, this antigen could improve LTBI diagnosis, even in BCG-vaccinated people.

No MeSH data available.


Related in: MedlinePlus

Heat map for IFN-γ responses to Mtb-Ag, Rv2626c, CFP-10 and ESAT-6 M. tuberculosis antigens in subjects without active tuberculosis.Heat map showing the IFN-γ responses to Mtb-Ag, Rv2626c, CFP-10 or ESAT-6 antigens as measured in cell free supernatants of peripheral blood mononuclear cells (PBMCs) from subjects without active tuberculosis (non-TB; n = 20). Colors represent pg/ml of IFN-γ produced in each individual, where high values are shown in red and low values in light yellow, as shown in the figure scale. Right column displays the result of QuantiFERON-TB Gold In-tube (QFT-GIT) test.
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f0005: Heat map for IFN-γ responses to Mtb-Ag, Rv2626c, CFP-10 and ESAT-6 M. tuberculosis antigens in subjects without active tuberculosis.Heat map showing the IFN-γ responses to Mtb-Ag, Rv2626c, CFP-10 or ESAT-6 antigens as measured in cell free supernatants of peripheral blood mononuclear cells (PBMCs) from subjects without active tuberculosis (non-TB; n = 20). Colors represent pg/ml of IFN-γ produced in each individual, where high values are shown in red and low values in light yellow, as shown in the figure scale. Right column displays the result of QuantiFERON-TB Gold In-tube (QFT-GIT) test.

Mentions: To assess the frequency of LTBI individuals among healthy BCG-vaccinated people highly exposed to M. tuberculosis, we analyzed the IFN-γ response to several dormancy (Rv2626c, Rv2628, Rv2624c) and specific early secretory (ESAT-6, CFP-10) antigens from the pathogen. Initially, IFN-γ production against the mentioned antigens or Mtb-Ag was evaluated in PBMCs from 20 healthy individuals. As shown by the heat map in Fig. 1, all subjects produced elevated amounts of IFN-γ against Mtb-Ag (> 600 pg/ml), as expected in BCG-vaccinated individuals. Interestingly, 7 out of 20 (35%) of the persons tested also responded simultaneously with high intensity to three antigens: Rv2626c, ESAT-6 and CFP-10. In fact, the three antigens induced > 600 pg/ml of IFN-γ in 5 out of the 7 subjects. The two exceptions were one individual in which Rv2626c and ESAT-6 induced 400–600 pg/ml and CFP-10 induced > 600 pg/ml of IFN-γ, and another person in which Rv2626c induced 200–400 pg/ml and CFP-10 and ESAT-6 induced > 600 pg/ml. In contrast to our data resulting from stimulation with Rv2626c, ESAT-6 and CFP-10 showing that 7 individuals simultaneously secreted high levels of IFN-γ to those antigens (all above 200 pg/ml), none of those subjects secreted IFN-γ against Rv2624c, and only 2 produced levels of IFN-γ above 200 pg/ml in response to Rv2628 stimulation (data not shown). Therefore, Fig. 1 represents the results obtained with antigens that displayed noticeable differences among individuals: Rv2626c, ESAT-6 and CFP-10.


A Mycobacterium tuberculosis Dormancy Antigen Differentiates Latently Infected Bacillus Calmette-Guérin-vaccinated Individuals.

Peña D, Rovetta AI, Hernández Del Pino RE, Amiano NO, Pasquinelli V, Pellegrini JM, Tateosian NL, Rolandelli A, Gutierrez M, Musella RM, Palmero DJ, Gherardi MM, Iovanna J, Chuluyan HE, García VE - EBioMedicine (2015)

Heat map for IFN-γ responses to Mtb-Ag, Rv2626c, CFP-10 and ESAT-6 M. tuberculosis antigens in subjects without active tuberculosis.Heat map showing the IFN-γ responses to Mtb-Ag, Rv2626c, CFP-10 or ESAT-6 antigens as measured in cell free supernatants of peripheral blood mononuclear cells (PBMCs) from subjects without active tuberculosis (non-TB; n = 20). Colors represent pg/ml of IFN-γ produced in each individual, where high values are shown in red and low values in light yellow, as shown in the figure scale. Right column displays the result of QuantiFERON-TB Gold In-tube (QFT-GIT) test.
© Copyright Policy - CC BY-NC-ND
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4563115&req=5

f0005: Heat map for IFN-γ responses to Mtb-Ag, Rv2626c, CFP-10 and ESAT-6 M. tuberculosis antigens in subjects without active tuberculosis.Heat map showing the IFN-γ responses to Mtb-Ag, Rv2626c, CFP-10 or ESAT-6 antigens as measured in cell free supernatants of peripheral blood mononuclear cells (PBMCs) from subjects without active tuberculosis (non-TB; n = 20). Colors represent pg/ml of IFN-γ produced in each individual, where high values are shown in red and low values in light yellow, as shown in the figure scale. Right column displays the result of QuantiFERON-TB Gold In-tube (QFT-GIT) test.
Mentions: To assess the frequency of LTBI individuals among healthy BCG-vaccinated people highly exposed to M. tuberculosis, we analyzed the IFN-γ response to several dormancy (Rv2626c, Rv2628, Rv2624c) and specific early secretory (ESAT-6, CFP-10) antigens from the pathogen. Initially, IFN-γ production against the mentioned antigens or Mtb-Ag was evaluated in PBMCs from 20 healthy individuals. As shown by the heat map in Fig. 1, all subjects produced elevated amounts of IFN-γ against Mtb-Ag (> 600 pg/ml), as expected in BCG-vaccinated individuals. Interestingly, 7 out of 20 (35%) of the persons tested also responded simultaneously with high intensity to three antigens: Rv2626c, ESAT-6 and CFP-10. In fact, the three antigens induced > 600 pg/ml of IFN-γ in 5 out of the 7 subjects. The two exceptions were one individual in which Rv2626c and ESAT-6 induced 400–600 pg/ml and CFP-10 induced > 600 pg/ml of IFN-γ, and another person in which Rv2626c induced 200–400 pg/ml and CFP-10 and ESAT-6 induced > 600 pg/ml. In contrast to our data resulting from stimulation with Rv2626c, ESAT-6 and CFP-10 showing that 7 individuals simultaneously secreted high levels of IFN-γ to those antigens (all above 200 pg/ml), none of those subjects secreted IFN-γ against Rv2624c, and only 2 produced levels of IFN-γ above 200 pg/ml in response to Rv2628 stimulation (data not shown). Therefore, Fig. 1 represents the results obtained with antigens that displayed noticeable differences among individuals: Rv2626c, ESAT-6 and CFP-10.

Bottom Line: LTBI subjects secreted significantly higher IFN-γ levels against Rv2626c than HD.Interestingly, whole blood stimulation with Rv2626c allowed the discrimination between active and latent infections, since TB patients did not secrete IFN-γ against Rv2626c, in contrast to CFP-10 + ESAT-6 stimulation that induced IFN-γ response from both LTBI and TB patients.ROC analysis confirmed that Rv2626c discriminated LTBI from HD and TB patients.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Química Biológica, Facultad de Ciencias Exactas y Naturales (IQUIBICEN), UBA (Universidad de Buenos Aires)-CONICET, Intendente Güiraldes 2160, Pabellón II, 4°piso, Ciudad Universitaria, C1428EGA Buenos Aires, Argentina ; Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, UBA, Intendente Güiraldes 2160, Pabellón II, 4°piso, Ciudad Universitaria, C1428EGA Buenos Aires, Argentina.

ABSTRACT
IFN-γ release assays (IGRAs) are better indicators of Mycobacterium tuberculosis infection than the tuberculin skin test (TST) in Bacillus Calmette-Guérin (BCG)-vaccinated populations. However, IGRAs do not discriminate active and latent infections (LTBI) and no gold standard for LTBI diagnosis is available. Thus, since improved tests to diagnose M. tuberculosis infection are required, we assessed the efficacy of several M. tuberculosis latency antigens. BCG-vaccinated healthy donors (HD) and tuberculosis (TB) patients were recruited. QuantiFERON-TB Gold In-Tube, TST and clinical data were used to differentiate LTBI. IFN-γ production against CFP-10, ESAT-6, Rv2624c, Rv2626c and Rv2628 antigens was tested in peripheral blood mononuclear cells. LTBI subjects secreted significantly higher IFN-γ levels against Rv2626c than HD. Additionally, Rv2626c peptide pools to which only LTBI responded were identified, and their cumulative IFN-γ response improved LTBI discrimination. Interestingly, whole blood stimulation with Rv2626c allowed the discrimination between active and latent infections, since TB patients did not secrete IFN-γ against Rv2626c, in contrast to CFP-10 + ESAT-6 stimulation that induced IFN-γ response from both LTBI and TB patients. ROC analysis confirmed that Rv2626c discriminated LTBI from HD and TB patients. Therefore, since only LTBI recognizes specific epitopes from Rv2626c, this antigen could improve LTBI diagnosis, even in BCG-vaccinated people.

No MeSH data available.


Related in: MedlinePlus