Immune response to Mycobacterium tuberculosis specific antigen ESAT-6 among south Indians.
The 6-kDa early secreted antigenic target (ESAT-6) is a T-cell antigen recognized by individuals infected with Mycobacterium tuberculosis. The aim of the study was to identify "protective epitopes" of ESAT-6 protein in the south Indian population. Proliferative and Interferon gamma (IFN-gamma) responses to ESAT-6 peptides were studied by flow cytometry and Enzyme linked immunosorbent assay (ELISA). Healthy household contacts (HHC) recognized Esp1 (10/17) and Esp6 (9/17) peptides. Among pulmonary tuberculosis patients (PTB), Esp1 (3/11) and Esp6 (5/11) were recognized. Maximal response (7/10) was found for Esp1 and Esp8 in treated patients (TR). Median values for the responding subjects gave the following results: Esp1 (76pg/ml), Esp6 (64pg/ml), induced IFN-gamma production in HHC; PTB gave low IFN-gamma responses for the peptides. TR responded to the peptides Esp1 (141pg/ml), Esp8 (102pg/ml). The proliferation of CD4 cells was similar in both PTB and TR for all peptides; but HHC showed an increase for Esp1 (p<0.05) and Esp6 (p<0.01). Esp1 (amino acids aa 1-20) and Esp6 (aa 51-70) were the immunogenic peptides recognized by the alleles HLA DRB1*04 and HLA DRB1*10 among HHC. But the association of the alleles with ESAT-6 peptide presentation needs to be confirmed in a large cohort of subjects. We speculate that ESAT-6 can be used along with other immune-eliciting proteins for vaccine design strategies in south Indian population.
Kumar
Madhan
M
Department of Immunology, Tuberculosis Research Centre (ICMR), Mayor V. R. Ramanathan Road, Chetput, Chennai - 600 031, India.
Meenakshi
N
N
Sundaramurthi
Jagadish C
JC
Kaur
Gurvinder
G
Mehra
Narinder K
NK
Raja
Alamelu
A
D000328:Adult; D000942:Antigens, Bacterial / Q000276:immunology*; D044466:Asian People; D001426:Bacterial Proteins / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000276:immunology*; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007194:India / Q000453:epidemiology; D007371:Interferon-gamma / Q000276:immunology*; D008213:Lymphocyte Activation; D008297:Male; D008875:Middle Aged; D014397:Tuberculosis, Pulmonary / Q000453:epidemiology / Q000235:genetics / Q000276:immunology*
D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C093276:ESAT-6 protein, Mycobacterium tuberculosis; D000939:Epitopes; D007371:Interferon-gamma