Recognition of stage-specific mycobacterial antigens differentiates between acute and latent infections with Mycobacterium tuberculosis.
Mycobacterium tuberculosis is estimated to infect 80 to 100 million people annually, the majority of whom do not develop clinical tuberculosis (TB) but instead maintain the infection in a latent state. These individuals generally become positive in response to a tuberculin skin test and may develop clinical TB at a later date, particularly if their immune systems are compromised. Latently infected individuals are interesting for two reasons. First, they are an important reservoir of M. tuberculosis, which needs to be considered for TB control. Second, if detected prior to recrudescence of the disease, they represent a human population that is making a protective immune response to M. tuberculosis, which is very important for defining correlates of protective immunity. In this study, we show that while responsiveness to early secretory antigenic target 6 is a good marker for M. tuberculosis infection, a strong response to the 16-kDa Rv2031c antigen (HspX or alpha-crystallin) is largely restricted to latently infected individuals, offering the possibility of differential immunodiagnosis of, or therapeutic vaccination against, TB.
Demissie
Abebech
A
Armauer Hansen Research Institute, Addis Ababa, Ethiopia.
Leyten
Eliane M S
EM
Abebe
Markos
M
Wassie
Liya
L
Aseffa
Abraham
A
Abate
Getahun
G
Fletcher
Helen
H
Owiafe
Patrick
P
Hill
Philip C
PC
Brookes
Roger
R
Rook
Graham
G
Zumla
Alimuddin
A
Arend
Sandra M
SM
Klein
Michel
M
Ottenhoff
Tom H M
TH
Andersen
Peter
P
Doherty
T Mark
TM
D000208:Acute Disease; D000942:Antigens, Bacterial / Q000276:immunology*; D001426:Bacterial Proteins / Q000276:immunology; D002353:Carrier State / Q000175:diagnosis / Q000276:immunology / Q000382:microbiology; D015331:Cohort Studies; D005002:Ethiopia; D005714:Gambia; D006801:Humans; D007159:Immunologic Tests; D066298:In Vitro Techniques; D007371:Interferon-gamma / Q000096:biosynthesis; D009169:Mycobacterium tuberculosis / Q000276:immunology* / Q000472:pathogenicity; D009426:Netherlands; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis / Q000276:immunology* / Q000382:microbiology*
D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C093276:ESAT-6 protein, Mycobacterium tuberculosis; C118127:HspX protein, Mycobacterium tuberculosis; D007371:Interferon-gamma