Mycobacterium tuberculosis peptides presented by HLA-E molecules are targets for human CD8 T-cells with cytotoxic as well as regulatory activity.
Tuberculosis (TB) is an escalating global health problem and improved vaccines against TB are urgently needed. HLA-E restricted responses may be of interest for vaccine development since HLA-E displays very limited polymorphism (only 2 coding variants exist), and is not down-regulated by HIV-infection. The peptides from Mycobacterium tuberculosis (Mtb) potentially presented by HLA-E molecules, however, are unknown. Here we describe human T-cell responses to Mtb-derived peptides containing predicted HLA-E binding motifs and binding-affinity for HLA-E. We observed CD8(+) T-cell proliferation to the majority of the 69 peptides tested in Mtb responsive adults as well as in BCG-vaccinated infants. CD8(+) T-cells were cytotoxic against target-cells transfected with HLA-E only in the presence of specific peptide. These T cells were also able to lyse M. bovis BCG infected, but not control monocytes, suggesting recognition of antigens during mycobacterial infection. In addition, peptide induced CD8(+) T-cells also displayed regulatory activity, since they inhibited T-cell proliferation. This regulatory activity was cell contact-dependent, and at least partly dependent on membrane-bound TGF-beta. Our results significantly increase our understanding of the human immune response to Mtb by identification of CD8(+) T-cell responses to novel HLA-E binding peptides of Mtb, which have cytotoxic as well as immunoregulatory activity.
Joosten
Simone A
SA
Department of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands.
van Meijgaarden
Krista E
KE
van Weeren
Pascale C
PC
Kazi
Fatima
F
Geluk
Annemieke
A
Savage
Nigel D L
ND
Drijfhout
Jan W
JW
Flower
Darren R
DR
Hanekom
Willem A
WA
Klein
Michèl R
MR
Ottenhoff
Tom H M
TH
D000328:Adult; D017951:Antigen Presentation / Q000276:immunology*; D000942:Antigens, Bacterial / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D002469:Cell Separation; D018984:Epitopes, T-Lymphocyte / Q000276:immunology; D005434:Flow Cytometry; D006680:HLA Antigens / Q000276:immunology*; D015395:Histocompatibility Antigens Class I / Q000276:immunology*; D006801:Humans; D007223:Infant; D008213:Lymphocyte Activation / Q000235:genetics / Q000276:immunology; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology; D014376:Tuberculosis / Q000276:immunology / Q000517:prevention & control; D032581:Tuberculosis Vaccines / Q000276:immunology; D000097625:HLA-E Antigens
D000942:Antigens, Bacterial; D018984:Epitopes, T-Lymphocyte; D006680:HLA Antigens; D015395:Histocompatibility Antigens Class I; D032581:Tuberculosis Vaccines; D000097625:HLA-E Antigens