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Mycobacterium tuberculosis epitope-specific interferon-g production in healthy Brazilians reactive and non-reactive to tuberculin skin test.

Silva BC, Grassi MF, Coutinho R, Mascarenhas RE, Olavarria VN, Coutinho-Borgo A, Kalil J, Cunha Neto E, Fonseca SG - Mem. Inst. Oswaldo Cruz (2014)

Bottom Line: We identified promiscuous and potentially protective CD4+ T-cell epitopes from the most conserved regions of MTB antigenic proteins by scanning the MTB antigenic proteins GroEL2, phosphate-binding protein 1 precursor and 19 kDa antigen with the TEPITOPE algorithm.Eighty-eight percent of TST-positive donors responded to at least one of the peptides, compared to 25% of TST-negative donors.The response to GroEL2 (463-477) was only observed in the TST-positive group.

View Article: PubMed Central - PubMed

Affiliation: Laboratório de Imunologia, Instituto do Coração, São Paulo, SP, Brasil.

ABSTRACT
The interferon (IFN)-γ response to peptides can be a useful diagnostic marker of Mycobacterium tuberculosis (MTB) latent infection. We identified promiscuous and potentially protective CD4+ T-cell epitopes from the most conserved regions of MTB antigenic proteins by scanning the MTB antigenic proteins GroEL2, phosphate-binding protein 1 precursor and 19 kDa antigen with the TEPITOPE algorithm. Seven peptide sequences predicted to bind to multiple human leukocyte antigen (HLA)-DR molecules were synthesised and tested with IFN-γ enzyme-linked immunospot (ELISPOT) assays using peripheral blood mononuclear cells (PBMCs) from 16 Mantoux tuberculin skin test (TST)-positive and 16 TST-negative healthy donors. Eighty-eight percent of TST-positive donors responded to at least one of the peptides, compared to 25% of TST-negative donors. Each individual peptide induced IFN-γ production by PBMCs from at least 31% of the TST-positive donors. The magnitude of the response against all peptides was 182 ± 230 x 106 IFN-γ spot forming cells (SFC) among TST-positive donors and 36 ± 62 x 106 SFC among TST-negative donors (p = 0.007). The response to GroEL2 (463-477) was only observed in the TST-positive group. This combination of novel MTB CD4 T-cell epitopes should be tested in a larger cohort of individuals with latent tuberculosis (TB) to evaluate its potential to diagnose latent TB and it may be included in ELISPOT-based IFN-γ assays to identify individuals with this condition.

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: magnitude of responses to Mycobacterium tuberculosispeptides. The bars represent the magnitude of response of each peptide(overall sum of spots of all individuals with positive responses). Positiveresponses > 30 spot forming cells (SFC) interferon (IFN)-γ/106 peripheralblood mononuclear cells (PBMCs) (p = 0.007, Mann-Whitney Utest). TST+: tuberculin skin test-positive; TST-: TST-negative.
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f03: : magnitude of responses to Mycobacterium tuberculosispeptides. The bars represent the magnitude of response of each peptide(overall sum of spots of all individuals with positive responses). Positiveresponses > 30 spot forming cells (SFC) interferon (IFN)-γ/106 peripheralblood mononuclear cells (PBMCs) (p = 0.007, Mann-Whitney Utest). TST+: tuberculin skin test-positive; TST-: TST-negative.

Mentions: The magnitude of responses to the peptides (sum of IFN-γ SFC of all peptides withpositive responses) was higher in the TST-positive group than in the TST-negative group(Fig. 3). The total number of IFN-γ SFC inresponse to MTB peptides was 182 ± 230 SFC/106 PBMCs among the TST-positivedonors, compared to 36 ± 62 SFC/106 PBMCs in the TST-negative donors (p =0.007). The magnitude of the responses per individual ranged from 0-725 SFC/106PBMCs among the TST-positive individuals and 0-170 SFCs/106 PBMCs amongthe TST-negative individuals (Table II).


Mycobacterium tuberculosis epitope-specific interferon-g production in healthy Brazilians reactive and non-reactive to tuberculin skin test.

Silva BC, Grassi MF, Coutinho R, Mascarenhas RE, Olavarria VN, Coutinho-Borgo A, Kalil J, Cunha Neto E, Fonseca SG - Mem. Inst. Oswaldo Cruz (2014)

: magnitude of responses to Mycobacterium tuberculosispeptides. The bars represent the magnitude of response of each peptide(overall sum of spots of all individuals with positive responses). Positiveresponses > 30 spot forming cells (SFC) interferon (IFN)-γ/106 peripheralblood mononuclear cells (PBMCs) (p = 0.007, Mann-Whitney Utest). TST+: tuberculin skin test-positive; TST-: TST-negative.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4325617&req=5

f03: : magnitude of responses to Mycobacterium tuberculosispeptides. The bars represent the magnitude of response of each peptide(overall sum of spots of all individuals with positive responses). Positiveresponses > 30 spot forming cells (SFC) interferon (IFN)-γ/106 peripheralblood mononuclear cells (PBMCs) (p = 0.007, Mann-Whitney Utest). TST+: tuberculin skin test-positive; TST-: TST-negative.
Mentions: The magnitude of responses to the peptides (sum of IFN-γ SFC of all peptides withpositive responses) was higher in the TST-positive group than in the TST-negative group(Fig. 3). The total number of IFN-γ SFC inresponse to MTB peptides was 182 ± 230 SFC/106 PBMCs among the TST-positivedonors, compared to 36 ± 62 SFC/106 PBMCs in the TST-negative donors (p =0.007). The magnitude of the responses per individual ranged from 0-725 SFC/106PBMCs among the TST-positive individuals and 0-170 SFCs/106 PBMCs amongthe TST-negative individuals (Table II).

Bottom Line: We identified promiscuous and potentially protective CD4+ T-cell epitopes from the most conserved regions of MTB antigenic proteins by scanning the MTB antigenic proteins GroEL2, phosphate-binding protein 1 precursor and 19 kDa antigen with the TEPITOPE algorithm.Eighty-eight percent of TST-positive donors responded to at least one of the peptides, compared to 25% of TST-negative donors.The response to GroEL2 (463-477) was only observed in the TST-positive group.

View Article: PubMed Central - PubMed

Affiliation: Laboratório de Imunologia, Instituto do Coração, São Paulo, SP, Brasil.

ABSTRACT
The interferon (IFN)-γ response to peptides can be a useful diagnostic marker of Mycobacterium tuberculosis (MTB) latent infection. We identified promiscuous and potentially protective CD4+ T-cell epitopes from the most conserved regions of MTB antigenic proteins by scanning the MTB antigenic proteins GroEL2, phosphate-binding protein 1 precursor and 19 kDa antigen with the TEPITOPE algorithm. Seven peptide sequences predicted to bind to multiple human leukocyte antigen (HLA)-DR molecules were synthesised and tested with IFN-γ enzyme-linked immunospot (ELISPOT) assays using peripheral blood mononuclear cells (PBMCs) from 16 Mantoux tuberculin skin test (TST)-positive and 16 TST-negative healthy donors. Eighty-eight percent of TST-positive donors responded to at least one of the peptides, compared to 25% of TST-negative donors. Each individual peptide induced IFN-γ production by PBMCs from at least 31% of the TST-positive donors. The magnitude of the response against all peptides was 182 ± 230 x 106 IFN-γ spot forming cells (SFC) among TST-positive donors and 36 ± 62 x 106 SFC among TST-negative donors (p = 0.007). The response to GroEL2 (463-477) was only observed in the TST-positive group. This combination of novel MTB CD4 T-cell epitopes should be tested in a larger cohort of individuals with latent tuberculosis (TB) to evaluate its potential to diagnose latent TB and it may be included in ELISPOT-based IFN-γ assays to identify individuals with this condition.

Show MeSH
Related in: MedlinePlus