title: Dynamic IgG antibody response to immunodominant antigens of M. tuberculosis for active TB diagnosis in high endemic settings.
abstract: BACKGROUND
  Even though various techniques have been developed for rapid diagnosis of tuberculosis (TB), still there is an immense need for a simple, cost effective, highly sensitive and specific test. Hence, one of the possibilities is identification of Mycobacterium tuberculosis specific antibodies in infected serum by using specific antigens.
  
  
  METHODS
  We tested 10 recombinant M. tuberculosis antigens to evaluate IgG levels among Healthy control subjects (HCS), Healthy household contacts (HHC) and pulmonary TB patients (PTB) by ELISA.
  
  
  RESULTS
  The median IgG levels specific to all the antigens are higher in PTB than HHC and HCS. Amongst single antigens, 38-kDa antigen has showed maximum sensitivity of 50% than any other antigens at 95.5% specificity. Among the two antigen combination, 38-kDa+Rv1860 has showed maximum sensitivity of 66.6% with specificity of 92.2%. The same antigen combination (38-kDa and Rv1860) predominantly identifies smear negative and culture positive TB patients with 68% sensitivity and 92.2% specificity. Most of the antigens have exhibited higher antibody titre in cavitary TB than non cavitary. With regard to latent TB infection (LTBI) identification, Rv1860 has exhibited maximum sensitivity of 53.3% with 95% specificity.
  
  
  CONCLUSIONS
  IgG response to combination of recombinant mycobacterial antigens (38-kDa, Rv1860, Rv2204c and Rv0753c) presents good specificity with acceptable level of sensitivity for TB diagnosis.
authors.affiliation: Department of Immunology, National Institute for Research in Tuberculosis (ICMR), No. 1, Mayor Sathyamoorthy Road, Chetput, Chennai 600 031, India.
authors.forename: Balaji
authors.initials: B
authors.lastname: Pathakumari
authors.affiliation: Department of Immunology, National Institute for Research in Tuberculosis (ICMR), No. 1, Mayor Sathyamoorthy Road, Chetput, Chennai 600 031, India.
authors.forename: Maddineni
authors.initials: M
authors.lastname: Prabhavathi
authors.affiliation: Department of Immunology, National Institute for Research in Tuberculosis (ICMR), No. 1, Mayor Sathyamoorthy Road, Chetput, Chennai 600 031, India.
authors.forename: Deenadayalan
authors.initials: D
authors.lastname: Anbarasu
authors.affiliation: Department of Immunology, National Institute for Research in Tuberculosis (ICMR), No. 1, Mayor Sathyamoorthy Road, Chetput, Chennai 600 031, India.
authors.forename: Pukazhvanthen
authors.initials: P
authors.lastname: Paramanandhan
authors.affiliation: Department of Immunology, National Institute for Research in Tuberculosis (ICMR), No. 1, Mayor Sathyamoorthy Road, Chetput, Chennai 600 031, India. Electronic address: alamelur@nirt.res.in.
authors.forename: Alamelu
authors.initials: A
authors.lastname: Raja
mesh_terms: D006801:Humans; D016056:Immunodominant Epitopes / Q000097:blood / Q000276:immunology*; D007074:Immunoglobulin G / Q000276:immunology*; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D011994:Recombinant Proteins / Q000276:immunology; D014376:Tuberculosis / Q000097:blood / Q000175:diagnosis* / Q000276:immunology*
chemical_list: D016056:Immunodominant Epitopes; D007074:Immunoglobulin G; D011994:Recombinant Proteins
keywords: ELISA; Immunoglobulin G; Latent tuberculosis; M. tuberculosis; Pulmonary tuberculosis; Recombinant proteins; Sero diagnosis