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Volume 48, Number 4, August 2015

Immune responses to latent tuberculosis antigen Rv2659c in Chinese populations 


Xue-juan Bai, Yan Liang, You-rong Yang, Ning Li, Xiao-yan Zhang, Hui-ru An, Jun-xian Zhang, Dan Chen, Lan Wang, Xue-qiong Wu


Received: February 20, 2014    Revised: February 26, 2014    Accepted: April 21, 2014   

 

Corresponding author:

Xue-qiong Wu
Army Tuberculosis Prevention and Control Key Laboratory, Institute for Tuberculosis Research, The 309th Hospital of Chinese PLA, Beijing 100091, PR China
Correspondence
Corresponding author. Army Tuberculosis Prevention and Control Key Laboratory, Institute of Tuberculosis Research, The 309th Hospital of Chinese PLA, Beijing 100091, PR China. 



 

Background and purpose: 

The latency-associated antigen Rv2659c is a starvation-related protein of Mycobacterium tuberculosis (M. tuberculosis). It has potential use in tuberculosis (TB) control, but its immunological characteristics in Chinese populations are unclear. 



 

Methods:

In this study, immunological characteristics and potential diagnostic use of recombinant Rv2659c protein were assessed. Interferon-γ (IFN-γ) production from peripheral blood mononuclear cells (PBMC) was assayed by enzyme-linked immunospot (ELISPOT) in TB patients (80 cases), individuals who were purified protein derivative (PPD)-positive after Bacillus Calmette-Guérin (BCG) vaccination (27 cases), nontuberculous respiratory disease patients (30 cases), individuals who were identified by standard techniques as having latent TB infection (LTBI) (37 cases), and uninfected healthy individuals (75 cases). Serum immunoglobulin G (IgG) levels were assayed by enzyme-linked immunosorbent assay (ELISA) in TB patients (43 cases), LTBI individuals (36 cases) and uninfected healthy individuals (66 cases).
 



 

Results:

When stimulated by rRv2659c, PBMC from LTBI individuals gave ELISPOT counts that were significantly higher than those from TB patients, BCG vaccinated individuals, non-TB respiratory disease patients and uninfected healthy individuals (p < 0.05). The rRv2659c stimulation gave detectable IFN-γ production in a higher proportion of persons with LTBI compared with TB patients and uninfected healthy individuals. BCG vaccination and non-TB respiratory disease had little influence on the PBMC response to rRv2659c. The levels of serum IgG specific for rRv2659c were not significantly different between LTBI individuals and TB patients (p > 0.05). 



 

Conclusion:

These results suggest that rRv2659c has potential for the diagnosis of LTBI. This is the first clinical report of human immune recognition of Rv2659c in Chinese populations. 



 

Key words:

latency antigen, Mycobacterium tuberculosis, Rv2659c, tuberculosis