title: Evaluation of gamma interferon immune response elicited by the newly constructed PstS-1(285-374):CFP10 fusion protein to detect Mycobacterium tuberculosis infection.
abstract: The PstS1 antigen is highly immunogenic, principally when combined with CFP10 during both latent and active TB infection. In the present study, a selected pstS1 gene fragment was cloned, fused with CFP10, and expressed in Escherichia coli. The product [PstS-1(285-374):CFP10] was compared to the recombinant fused RD1 (region of deletion 1) protein (ESAT-6:CFP10) in detecting Mycobacterium tuberculosis infection in 108 recent contacts of pulmonary tuberculosis (TB) cases, considering a positive tuberculin skin test (TST) to be the baseline. The release of gamma interferon (IFN-γ) in 22-h whole-blood and 5-day lymphocyte stimulation assays primed with each antigen was determined. All contacts were clinically followed for up to 1 year, and 87% of the tuberculin skin test-positive (TST(positive)) patients accepted preventative treatment. Concerning the IFN-γ response to PstS-1(285-374):CFP10 in the 22-h and 5-day assays, a slight increase in contact-TST(positive) detection was observed (23/54 and 26/54) compared to the level seen with the RD1 protein (18/54 and 24/54) whereas in the TST(negative) group, similarly lower numbers (≤5/48) of responders were achieved for both antigens, except for RD1 in the 5-day assay (8/48). By combining the IFN-γ responders to both antigens in the 5-day assays, slightly higher increases in positivity were found in the TST(positive) (32/54) and TST(negative) (10/48) groups. Two of 12 untreated TST(positive) contacts progressed to active TB and were concordantly positive in all assays, except for one contact who lacked positivity in the RD1 5-day assay. We demonstrated for the first time that PstS-1(285-374):CFP10 slightly increased contact positivity and detection of active disease progression, suggesting its potential application as a TB infection marker.
authors: Laboratory of Cellular Microbiology, Oswaldo Cruz Institute, Fiocruz, Rio de Janeiro, RJ, Brazil.
authors: Leonardo Silva de
authors: LS
authors: Araujo
authors: Fernanda Carvalho de Queiroz
authors: FC
authors: Mello
authors: Nidai de Bárbara Moreira da
authors: Nde B
authors: Silva
authors: Janaina Aparecida Medeiros
authors: JA
authors: Leung
authors: Silvia Maria Almeida
authors: SM
authors: Machado
authors: Isabela Gama
authors: IG
authors: Sardella
authors: Renata de Moraes
authors: Rde M
authors: Maciel
authors: Maria Helena Féres
authors: MH
authors: Saad
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000942:Antigens, Bacterial / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D001769:Blood / Q000276:immunology; D004926:Escherichia coli / Q000235:genetics; D005260:Female; D015870:Gene Expression; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism*; D059425:Interferon-gamma Release Tests / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011993:Recombinant Fusion Proteins / Q000235:genetics; D012680:Sensitivity and Specificity; D013997:Time Factors; D014376:Tuberculosis / Q000175:diagnosis* / Q000276:immunology; D055815:Young Adult
chemical_list: D018528:ATP-Binding Cassette Transporters; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C117940:CFP-10 protein, Mycobacterium tuberculosis; C581205:PstS-1 protein, Mycobacterium tuberculosis; D011993:Recombinant Fusion Proteins; D007371:Interferon-gamma