title: Expression of SA5K, a secretion antigen of Mycobacterium tuberculosis, inside human macrophages and in sputum from tuberculosis patients.
abstract: An 8.3 kDa protein (SA5K), secreted by Mycobacterium tuberculosis/Mycobacterium bovis bacillus Calmette-Guérin (BCG) in culture filtrate, has been previously described in our laboratory. In the present study, analysis of the distribution of SA5K gene (Rv1174c) among M. tuberculosis strains, isolated from a wide variety of clinical specimens, revealed that the gene is present in all clinical isolates analyzed (29/29). SA5K expression inside human macrophages infected with BCG was demonstrated by reverse transcription-polymerase chain reaction (RT-PCR) on RNA extracted from bacterial cells following 24 and 48 h of infection. In addition, in order to evaluate whether SA5K gene was also expressed at the site of infection in the lung, a nested RT-PCR assay was developed to detect specific mRNA in sputum samples collected from smear positive tuberculosis patients. SA5K mRNA was detected in all the samples containing high numbers of tubercle bacilli demonstrating that the corresponding gene is expressed during the course of clinical infection.
authors.affiliation: Dipartimento di Patologia Sperimentale, Biotecnologie Mediche, Infettivologia ed Epidemiologia, Università degli Studi di Pisa, Via S. Zeno 35-39, 56127 Pisa, Italy.
authors.forename: Daria
authors.initials: D
authors.lastname: Bottai
authors.forename: Giovanna
authors.initials: G
authors.lastname: Batoni
authors.forename: Semih
authors.initials: S
authors.lastname: Esin
authors.forename: Giuseppantonio
authors.initials: G
authors.lastname: Maisetta
authors.forename: Manuela
authors.initials: M
authors.lastname: Pardini
authors.forename: Walter
authors.initials: W
authors.lastname: Florio
authors.forename: Laura
authors.initials: L
authors.lastname: Rindi
authors.forename: Carlo
authors.initials: C
authors.lastname: Garzelli
authors.forename: Mario
authors.initials: M
authors.lastname: Campa
mesh_terms: D000217:Acyltransferases / Q000032:analysis / Q000235:genetics; D000942:Antigens, Bacterial / Q000032:analysis / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D015139:Blotting, Southern; D002460:Cell Line; D004269:DNA, Bacterial / Q000302:isolation & purification; D015964:Gene Expression Regulation, Bacterial; D006801:Humans; D008264:Macrophages / Q000382:microbiology*; D009163:Mycobacterium bovis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism / Q000502:physiology; D009169:Mycobacterium tuberculosis / Q000235:genetics* / Q000254:growth & development / Q000502:physiology; D012329:RNA, Bacterial / Q000032:analysis; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013183:Sputum / Q000382:microbiology*; D014376:Tuberculosis / Q000382:microbiology* / Q000473:pathology
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D012329:RNA, Bacterial; D012333:RNA, Messenger; C430090:Rv1174c protein, Mycobacterium tuberculosis; D000217:Acyltransferases; C121433:antigen 85B, Mycobacterium tuberculosis