Pharmaceutical composition containing at least one peptide or protein (fragment) with an immunomodulatory activity together with an adjuvant. The peptide is derived from a pathogenic agent or a tumour antigen. The adjuvant is capable of increasing the binding of the peptide to the cells of the individual to be treated or of increasing the entry of the peptide into the cells and strengthening the immunomodulatory activity of the peptide. Preferred adjuvants are basic polyamino acids such as polyarginine or polylysine, optionally conjugated with a cellular ligand such as a carbohydrate group or transferrin. The composition is particularly intended for use as a vaccine, e.g. as a tumour vaccine.