Identification of mycobacterial bacterioferritin B for immune screening of tuberculosis and latent tuberculosis infection.

Abstract

OBJECTIVES:

It remains necessary and urgent to search for novel mycobacterial antigens to increase the sensitivity and specificity for tuberculosis (TB) diagnosis and latent TB infection (LTBI) screening. Antigens capable of inducing strong immune responses during Mycobacterium tuberculosis (M.tb) infection would be good candidates.

METHODS:

Cellular responses specific to M.tb derived bacterioferritin B (BfrB) were assessed by IFN-γ ELISPOT in three human cohorts, including healthy controls (HCs), LTBI population and pulmonary TB (PTB) patients. Its significance in TB diagnosis and LTBI identification was further analyzed.

RESULTS:

BfrB-specific IFN-γ responses in PTB and LTBI groups were significantly higher than that in HCs. However, BfrB-specific IFN-γ release was not as strong as that to ESAT-6 or CFP-10 in PTB patients whereas comparable in LTBI cohort with possible complementary properties to ESAT-6 or CFP-10. More interestingly, there were a considerable number of HCs with high BfrB-specific cellular responses. When HCs with high BfrB-specific cellular responses were subgrouped into ESAT-6/CFP-10hi (SFUs = 3, 4, 5) and ESAT-6/CFP-10lo (SFUs < 3) groups, those who belonged to ESAT-6/CFP-10hi group exhibited higher PPD responsiveness than ESAT-6/CFP-10lo group.

CONCLUSIONS:

PTB and LTBI groups exhibit higher BfrB-specific IFN-γ responses than HCs. Although BfrB is not as immunodominant as ESAT-6/CFP-10 during acute M.tb infection, comparable BfrB-specific cellular immune responses are observed in LTBI population with the potential to increase the sensitivity for LTBI screening. Moreover, strong BfrB-specific IFN-γ release in the healthy cohort is probably cautionary in identifying leaky LTBI from HCs. BfrB might thus be considered as an additional biomarker antigen for LTBI identification.

• Authors: Xinyu Yang, Jia-Bao Wu, Ying Liu, Yanqing Xiong, Ping Ji, Shu-Jun Wang, Yingying Chen, Guo-Ping Zhao, Shui-Hua Lu, Ying Wang
• Journal: Tuberculosis (Edinburgh, Scotland) (Tuberculosis (Edinb)) Vol. 107 Pg. 119-125 (12 2017) ISSN: 1873-281X [Electronic] Scotland
• PMID: 29050758 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2017 Elsevier Ltd. All rights reserved.

Chemical References

• Antigens, Bacterial
• Bacterial Proteins
• CFP-10 protein, Mycobacterium tuberculosis
• Cytochrome b Group
• ESAT-6 protein, Mycobacterium tuberculosis
• Immunodominant Epitopes
• Ferritins
• bacterioferritin

Topics

• Adult
• Aged
• Aged, 80 and over
• Antigens, Bacterial (immunology)
• Bacterial Proteins (immunology)
• Case-Control Studies
• Cytochrome b Group (immunology)
• Enzyme-Linked Immunospot Assay
• Female
• Ferritins (immunology)
• Host-Pathogen Interactions
• Humans
• Immunity, Cellular
• Immunodominant Epitopes
• Interferon-gamma Release Tests
• Latent Tuberculosis (diagnosis, immunology, microbiology)
• Leukocytes, Mononuclear (immunology, microbiology)
• Male
• Middle Aged
• Mycobacterium tuberculosis (immunology)
• Predictive Value of Tests
• Reproducibility of Results
• Tuberculosis, Pulmonary (diagnosis, immunology, microbiology)
• Young Adult