HLA-DR-restricted peptides identified in the Nef protein can induce HIV type 1-specific IL-2/IFN-gamma-secreting CD4+ and CD4+ /CD8+ T cells in humans after lipopeptide vaccination.
We screened the Neflaiprotein to identify new HLA-DR-restricted epitopes, because this small protein is expressed early during infection, and specific CD4(+) T cells are critical for effective immunity in HIV-1 infection. We synthesized a set of peptides that covers the sequence of the Nef protein, and performed binding assays using 10 common HLA-DR molecules. We defined four large regions in this protein able to bind very efficiently to eight HLADR molecules. We took advantage of healthy volunteers immunized with an HIV-1 lipopeptide vaccine that contains three of the four HLA DR-restricted regions to investigate their capacities to stimulate T cells. In 11 vaccinated volunteers, typed for their class II molecules, we were able to correlate sequences of the vaccine displaying binding activities to specific HLA-DR molecules and the induction of CD4(+) T cell proliferation. To identify potential HLA-DR epitopes, we synthesized 31 15-mer peptides and showed that 26 bound to one or more HLA-DR molecules. Interestingly, 12 of the 26 15-mer peptides identified are included in the sequence of lipopeptides. We used IFN-gamma ELISPOT and flow cytometer assays to investigate the capacity of these potential CD4(+) T cell epitopes to induce specific T cell responses. We showed that seven of these peptides were able to stimulate HIV-specific T cell responses in five of six tested volunteers. These cells are Nef-specific CD4(+) and CD4(+) CD8(+) T cells secreting IL-2/INF-gamma or IL-2 alone. To conclude, these 26 Nef HLA-DR-restricted peptides could be helpful to better evaluate CD4(+) deficiencies in HIV infection and, for new vaccine designs.
Gahery
Hanne
H
INSERM U567, 75014 Paris, France. gahery@cochin.inserm.fr
Figueiredo
Suzanne
S
Texier
Catherine
C
Pouvelle-Moratille
Sandra
S
Ourth
Lucie
L
Igea
Céline
C
Surenaud
Mathieu
M
Guillet
Jean-Gérard
JG
Maillere
Bernard
B
D016915:AIDS Vaccines / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000821:virology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000821:virology; D004353:Drug Evaluation, Preclinical; D015693:Gene Products, nef / Q000276:immunology*; D015658:HIV Infections / Q000276:immunology* / Q000517:prevention & control; D015497:HIV-1 / Q000276:immunology*; D006684:HLA-DR Antigens / Q000276:immunology*; D006801:Humans; D016056:Immunodominant Epitopes / Q000737:chemistry / Q000276:immunology; D008213:Lymphocyte Activation; D022223:Vaccines, Subunit / Q000276:immunology; D054311:nef Gene Products, Human Immunodeficiency Virus
D016915:AIDS Vaccines; D015693:Gene Products, nef; D006684:HLA-DR Antigens; D016056:Immunodominant Epitopes; D022223:Vaccines, Subunit; D054311:nef Gene Products, Human Immunodeficiency Virus; C514837:nef protein, Human immunodeficiency virus 1