The invention involves peptides of from about 7 to about 50 amino acid residues in length that have epitopes that bind to more than one HLA class II protein and stimulate CD4+ T cells for treatment of cancer from one of three serine proteases over expressed in ovarian cancer and other cancers—stratum corneum chymotryptic enzyme, matriptase, and hepsin. Since the peptides bind to more than one HLA class II protein variant, they can be used to treat cancer in most patients of a population having a variety of HLA class II alleles. The peptides can be loaded onto autologous dendritic cells of a cancer patient and infused into the patient to activate a CD4+ and CD8+ T cell response that recognizes tumor cells expressing the peptide antigen.
1. A purified peptide of 12-50 amino acid residues comprising an antigenic stratum corneum chymotryptic enzyme (SCCE) sequence of 12-50 amino acid residues; wherein when the purified peptide is contacted with dendritic cells to generate peptide-loaded dendritic cells and the peptide-loaded dendritic cells are contacted with T cells, the peptide-loaded dendritic cells amplify CD4+ T cells (helper T cells) that recognize the SCCE sequence; wherein the antigenic SCCE sequence is SEQ ID NO:15 (residues 1-23 of SCCE), SEQ ID NO:16 (residues 61-84), SEQ ID NO:17 (residues 143-160), or a fragment thereof that comprises at least 12 consecutive amino acid residues of SEQ ID NO:15, at least 12 consecutive amino acid residues of SEQ ID NO:16, or at least 12 consecutive amino acid residues of SEQ ID NO:17.