T cell response to alpha crystallin and Mycobacterium tuberculosis specific antigens using ex-vivo elispot assay for detecting latent tuberculosis infection in Addis Ababa, Ethiopia.
BACKGROUND
Mycobacterium tuberculosis (Mtb) persists in a state of non-replication or stationary phase, but resulting in active tuberculosis (TB) when the immune system is suppressed. Alpha-crystallin (ACR) is one of the bacterial antigens characterized known to be related to shifting of the bacilli from growth to a non-replicating persistent state.


OBJECTIVE
To compare the ex-vivo responsiveness of active TB patients, close household contacts and healthy controls to specific Mtb antigens.


METHODS
Antigen-specific interferon-gamma (IFN-g) responses were measured to a 16kDa-alpha crystallin (ACR) antigen along with its peptides and other Mtb antigens (ESAT-6, CFP-10, PPD, TB10.3 and Ag85A) in 39 active TB patients, 23 close household contacts and 25 community controls, using ex-vivo ELISPOT RESULT: The proportion of responders to ACR was 36% in active TB patients (76 +/- 14 spot forming cells), 48% in close household contacts (123 +/- 31 spot forming cells) and 76% in community controls (165 +/- 29 spot forming cells) indicating the presence of latency more in the community controls compared to the other groups. Sixty percent of community controls (131 +/- 27 spot forming cells), 61% of healthy household contacts (138 +/- 3 spot forming cells) and 54% of TB patients (198 +/- 37 spot forming cells) showed ESAT-6-specific T cell responses.


CONCLUSIONS
Antigen specific T cell response based on ex-vivo ELISPOT assay using combined ACR and ESAT-6/ CFP-10 antigens can be used as indicator of underlying latent TB infection in tropical setting where tuberculosis is endemic.
Gezahegne
G
Mamo
Adane
A
Mihret
Mesfin
M
Taffesse
Girmai
G
Gebru
Mekbeb
M
Afework
Lawerence K
LK
Yamuah
Liya
L
Wassie
Markos
M
Abebe
Abraham
A
Aseffa
Shreemantha K
SK
Parida
D000293:Adolescent; D000328:Adult; D000942:Antigens, Bacterial / Q000276:immunology; D001426:Bacterial Proteins / Q000276:immunology; D015415:Biomarkers / Q000378:metabolism; D016022:Case-Control Studies; D058501:Enzyme-Linked Immunospot Assay / Q000379:methods; D005002:Ethiopia; D005260:Female; D006801:Humans; D055985:Latent Tuberculosis / Q000175:diagnosis* / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013601:T-Lymphocytes / Q000276:immunology*; D038201:alpha-Crystallins / Q000276:immunology*
D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D015415:Biomarkers; C117940:CFP-10 protein, Mycobacterium tuberculosis; C093276:ESAT-6 protein, Mycobacterium tuberculosis; D038201:alpha-Crystallins