Modulation of antigen immunogenicity by addition of epitopes recognized by NKT cells

A method of activating NKT cells in a mammal, the method comprising

• identifying a peptide or polypeptide that does not activate NKT cells when the peptide or polypeptide is incubated with a cell line expressing CD1d and NKT cells;
• introducing at least one, or at least one additional, CD1d binding motif comprising [FWHY]-X2X3-[ILMV]-X5X6-[FWHY] into the peptide or polypeptide so as to generate a modified peptide or polypeptide;
• selecting a modified peptide or polypeptide that activates NKT cells;
• and
• administering the said modified peptide or polypeptide that activates NKT cells to the mammal, wherein the NKT cells are Type I NKT cells,
• wherein identifying a peptide or polypeptide that does not activate NKT cells comprises determining the capacity of the peptide or polypeptide to bind to CD1d, and, for peptides or polypeptides having the capacity to bind to CD1d, determining the ability to activate NKT cells by incubation of the modified peptide or polypeptide with cells expressing CD1d, followed by addition of a population of NKT cells, and detecting NKT cell activation.

A method of treating a tumor in a mammalian subject, the method comprising

• identifying a peptide or polypeptide from the tumor, in the mammalian subject, wherein the peptide or polypeptide does not activate NKT cells when the peptide or polypeptide is incubated with a cell line expressing CD1d and NKT cells;
• introducing at least one, or at least one additional, CD1d binding motif comprising [FWHY]-X2X3-[ILMV]-X5X6-[FWHY] into the said peptide or polypeptide so as to generate a modified peptide or polypeptide;
• selecting a modified peptide or polypeptide that activates NKT cells when the peptide or polypeptide is incubated with a cell line expressing CD1d and NKT cells, and that activates cytolytic activity and cytokine production by CD4+ NKT cells when administered to a mammalian subject;
• administering the modified peptide or polypeptide to the mammalian subject in need of treatment;
• wherein identifying a peptide or polypeptide that does not activate NKT cells comprises determining the capacity of the peptide or polypeptide to bind to CD1d, and, for peptides or polypeptides having the capacity to bind to CD1d, determining the ability to activate NKT cells by incubation of the modified peptide or polypeptide with cells expressing CD1d, followed by addition of a population of NKT cells, and detecting NKT cell activation.