title: Simultaneous detection of IgG and IgM antibodies against a recombinant polyprotein PstS1-LEP for tuberculosis diagnosis.
abstract: BACKGROUND
  Commercial serological tests for the diagnosis of tuberculosis (TB) show poor sensitivity and specificity, and a new approach to antigen screening is required to improve the accuracy of serodiagnosis.
  
  
  METHODS
  Using an indirect enzyme-linked immunosorbent assay (ELISA), we evaluated the responses of IgG and IgM antibodies to the recombinant PstS1-LEP protein expressed in Escherichia coli, a polyprotein of PstS1 and line multi-epitopes polypeptide (LEP).
  
  
  RESULTS
  The mixture of anti-human IgG and IgM added to a well [Ig(G + M)], which was different from the combination of IgG and IgM (IgG + IgM), had a stronger immunoreactivity to PstS1-LEP than the single antibody. IgG and Ig(G + M), but not IgM against the PstS1-LEP protein effectively distinguished TB patients from patients with nontuberculous pulmonary disease (NTBPD) and healthy controls (HCs). Compared with IgG, the sensitivities of Ig(G + M) and IgG + IgM varied from 71.4% to 77.6% and 72.7% in pulmonary TB (PTB) patients and from 42.1% to 64.0% and 55.8% in extrapulmonary TB (EPTB) patients, respectively. The specificity of Ig(G + M) did not decrease, and was higher than that provided by IgG + IgM in HCs with positive tuberculin skin test.
  
  
  CONCLUSIONS
  These findings suggest that PstS1-LEP can act as a candidate for detecting Ig(G + M) in serum from PTB and EPTB patients.
authors.affiliation: From the 1 Central Laboratory, Beijing Key Laboratory of Organ Transplantation and Immunology Regulation, 309th Hospital of the Chinese People's Liberation Army , Beijing , China.
authors.forename: Jun-Li
authors.initials: JL
authors.lastname: Li
authors.forename: Xiang-Yu
authors.initials: XY
authors.lastname: Huang
authors.forename: Hong-Bing
authors.initials: HB
authors.lastname: Chen
authors.forename: Xin-Jing
authors.initials: XJ
authors.lastname: Wang
authors.forename: Chuan-Zhi
authors.initials: CZ
authors.lastname: Zhu
authors.forename: Ming
authors.initials: M
authors.lastname: Zhao
authors.forename: Qing-De
authors.initials: QD
authors.lastname: Song
authors.forename: Hai-Yan
authors.initials: HY
authors.lastname: Huang
authors.forename: Li
authors.initials: L
authors.lastname: Xiao
authors.forename: Xiu-Yun
authors.initials: XY
authors.lastname: He
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000737:chemistry / Q000276:immunology*; D000907:Antibodies, Bacterial / Q000097:blood* / Q000276:immunology; D001426:Bacterial Proteins / Q000737:chemistry / Q000276:immunology*; D002681:China; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood* / Q000276:immunology; D007075:Immunoglobulin M / Q000097:blood* / Q000276:immunology; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000276:immunology*; D014376:Tuberculosis / Q000175:diagnosis* / Q000276:immunology
chemical_list: D018528:ATP-Binding Cassette Transporters; D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D007074:Immunoglobulin G; D007075:Immunoglobulin M; C581205:PstS-1 protein, Mycobacterium tuberculosis; D011993:Recombinant Fusion Proteins
keywords: ELISA; Ig(G + M); Line multi-epitope polypeptide; tuberculosis