Immunogenic peptides for use in the prevention and/or treatment of infectious diseases, autoimmune diseases, immune responses to allofactors, allergic diseases, tumors, graft rejection and immune responses against viral vectors used for gene therapy or gene vaccination
The invention describes new peptides containing epitopes recognized by CD4+ natural killer T (NKT) cells for increasing activity for use in infectious diseases, autoimmune diseases, immune reaction to administration of allofactors, allergic diseases, therapy of tumors, prevention of graft rejection and prevention of immunization against viral proteins used in gene therapy or gene vaccination.
1. A method for preparing a peptide capable of eliciting NKT cell activation, said method comprising the steps of:
(1) identifying within an antigenic protein a NKT cell epitope sequence comprising a [FWHY]-xx-[ILMV]-xx-[FWHY] motif, wherein x is any amino acid, wherein [FWHY] is an amino acid selected from Phe, Trp, His, and Tyr, and wherein [ILMV] is an amino acid selected from Ile, Leu, Met, and Val,
(2) testing a peptide with a NKT cell epitope sequence identified in step (1) in vitro for activation of NKT cells when said peptide is presented by CD1d, and
(3) providing a peptide comprising:
a NKT cell epitope tested in step (2) and having confirmed activation of NKT cells, linked to
a thioreductase [CST]-xx-C or C-xx-[CST] motif, wherein x is any amino acid, and wherein [CST] is an amino acid selected from Cys, Ser, and Thr, such that said thioreductase motif and said NKT cell epitope sequence are either immediately adjacent to each other or separated by a linker of at most 7 amino acids in length.
2. The method according to claim 1 , wherein said antigenic protein is selected from the group consisting of an autoantigen, an allofactor, an allergen, a tumor associated antigen, an alloantigen shed by a graft, an antigen from a viral vector used for gene therapy or gene vaccination, and an intracellular pathogen associated antigen.
3. The method according to claim 1 , wherein said thioreductase motif and said NKT cell epitope are either immediately adjacent to each other or separated by a linker of at most 4 amino acids in length.
4. The method according to claim 1 wherein said antigenic protein does not comprise a [CST]-xx-C or C-xx-[CST] motif within 11 amino acids N- or C terminally adjacent to said NKT cell epitope.
5. The method according to claim 1 , comprising in step (1) identifying within an antigenic protein a NKT cell epitope sequence comprising a [FW]-xx-[ILMV]-xx-[FW] motif, wherein [FW] is Phe or Trp.
6. The method according to claim 1 , comprising in step (1) identifying within an antigenic protein a NKT cell epitope sequence comprising a [FW]-xx-[ILM]-xx-[FW] motif, wherein [ILM] is an amino acid selected from Ile, Leu, and Met.
7. The method according to claim 1 , wherein said thioreductase motif is C-xx-C.
8. The method according to claim 7 , wherein x stands for any amino acid except tyrosine, phenylalanine, and tryptophan.