RESUMO
BACKGROUND: Culture filtrate proteins secreted by mycobacteria are thought to play an important role in inducing protective immunity and to develop new methods for diagnosing tuberculosis. METHODS: A culture filtrate protein of M. avium that was strongly reactive with goat antiserum against M. intracellulare was constructed. Its homologous protein (TB-14) in M. tuberculosis was cloned, expressed and purified. The inductions of IFN-gamma stimulated with 10 microgram of TB-14 recombinant protein and 10 microgram PPD were estimated by using whole bloods from seven PPD (-) subjects, seven PPD (+) healthy volunteers and nine tuberculosis patients. RESULTS: M. avium culture filtrate protein was confirmed as a hypothetical protein that was termed contig 116. A novel 14-kDa recombinant protein (TB-14) of M. tuberculosis was composed of 148 amino acids, including 30 amino acids of the signal peptide, and it showed 78% homology with M. avium. In the PPD (+) healthy volunteers, recombinant TB-14 protein strongly induced the secretion of IFN-gamma in whole blood cultures. CONCLUSION: These results suggest that TB-14 recombinant protein might play an important role in inducing cell-mediated immunity against tuberculosis. Furthermore, TB-14 protein antigen and its antiserum will be available for the development of new diagnostic tools for tuberculosis.
Assuntos
Humanos , Aminoácidos , Células Clonais , Cabras , Voluntários Saudáveis , Imunidade Celular , Mycobacterium tuberculosis , Mycobacterium , Sinais Direcionadores de Proteínas , TuberculoseRESUMO
Mycobacterium tuberculosis is capable of growing and survival within macrophage. The purpose of this study was to identify the genes regulated by infection of mycobacteria in human monocytic THP-1 cells. We used the differential display reverse transcriptase polymerase chain reaction (DD RT-PCR) and nothern blot analysis to confirm the differentially expressed genes from THP-1 cells infected with live Mycobacterium tuberculosis H37Rv, heat-kille Mycobacterium tuberculosis H37Rv and live Mycobacterium bovis BCG. Among many up or down-regulated clones, 27 clones were sequenced and compared with known genes on GenBank. Thirteen of over-expressed clones from THP-1 cells infected with live Mycobacterium tuberculosis H37Rv were identical to human prothymosin alpha, eight were novel clones and six clones showed homology with Human ferritin H chain, Escherichia coli bgl, Mouse RNA-dependent EIF-2 alpha kinase, E. coli htrL, Hyaluronan receptor and T cell receptor. Our result suggests that Mycobacterium tuberculosis might regulate prothymosin alpha gene transcription in monocytic THP-1 cell.