title: Characterization of culture filtrate proteins Rv1197 and Rv1198 of ESAT-6 family from Mycobacterium tuberculosis H37Rv.
abstract: We have characterized two immunogenic proteins, Rv1197 and Rv1198, of the Esx-5 system of the ESAT-6 family of Mycobacterium tuberculosis H37Rv.
  
  
  
  The complex formation between Rv1197 and Rv1198 was characterized by biophysical techniques. The reactivity of serum from TB patients towards these proteins was characterized by ELISA. Lymphocyte proliferation and cytokine induction were followed in restimulated splenocytes from immunized mice by using MTT assay and CBA flowcytometry, respectively.
  
  
  
  Rv1197 and Rv1198 strongly interact to form a heterodimeric complex under reducing conditions, which is characterized by a dissociation constant of 97×10-9M and melting temperature, Tm, of 50.5°C. Strong humoral responses to Rv1197, Rv1198, CFP-10 and MoaC1 (Rv3111) antigens were found in Indian patients with active pulmonary tuberculosis (n=44), in comparison to non-infected healthy individuals (n=20). The seroreactivity to Rv1198 was characterized by a sensitivity of 75% and specificity of 90%. In BALB/c mice, immunization with Rv1198-FIA induced a pro-inflammatory response with elevated levels of TNF and IL-6, along with low induction of IFN-γ, IL-2 and IL-10, but no induction of IL-4.
  
  
  
  Rv1197 and Rv1198 form a stable complex, which is regulated by the redox state of Rv1198. Rv1198 is immunogenic with highly specific seroreactivity towards TB patients' serum. Rv1198 elicits a pro-inflammatory recall response in immunized mice.
  
  
  
  This study characterizes the interaction of Rv1197 and Rv1198, and establishes the immunogenic nature of Rv1198.
authors.affiliation: Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Lucknow 226031, India.
authors.forename: Himanshu
authors.initials: H
authors.lastname: Pandey
authors.affiliation: Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Lucknow 226031, India.
authors.forename: Sarita
authors.initials: S
authors.lastname: Tripathi
authors.affiliation: Department of Respiratory Medicine, King George's Medical University, Lucknow 226003, India.
authors.forename: Kanchan
authors.initials: K
authors.lastname: Srivastava
authors.affiliation: Microbiology Division, CSIR-Central Drug Research Institute, Lucknow 226031, India.
authors.forename: Dinesh K
authors.initials: DK
authors.lastname: Tripathi
authors.affiliation: Parasitology Division, CSIR-Central Drug Research Institute, Lucknow 226031, India.
authors.forename: Mrigank
authors.initials: M
authors.lastname: Srivastava
authors.affiliation: Department of Respiratory Medicine, King George's Medical University, Lucknow 226003, India.
authors.forename: Surya
authors.initials: S
authors.lastname: Kant
authors.affiliation: Microbiology Division, CSIR-Central Drug Research Institute, Lucknow 226031, India. Electronic address: kishore@cdri.res.in.
authors.forename: Kishore K
authors.initials: KK
authors.lastname: Srivastava
authors.affiliation: Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Lucknow 226031, India. Electronic address: ashish_arora@cdri.res.in.
authors.forename: Ashish
authors.initials: A
authors.lastname: Arora
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000378:metabolism*; D000328:Adult; D000818:Animals; D000942:Antigens, Bacterial / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism*; D049109:Cell Proliferation / Q000502:physiology; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism; D016753:Interleukin-10 / Q000378:metabolism; D007376:Interleukin-2 / Q000378:metabolism; D015847:Interleukin-4 / Q000378:metabolism; D008214:Lymphocytes / Q000382:microbiology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000378:metabolism*; D014397:Tuberculosis, Pulmonary / Q000382:microbiology; D055815:Young Adult
chemical_list: D018528:ATP-Binding Cassette Transporters; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D007376:Interleukin-2; C519050:Rv1258c protein, Mycobacterium tuberculosis; D016753:Interleukin-10; D015847:Interleukin-4; D007371:Interferon-gamma
keywords: ESAT-6 family; Mycobacterium tuberculosis; Rv1197; Rv1198; Seroreactivity; Vaccine