The present invention relates to a method of treating or preventing melanoma using vaccination or immunisation, wherein said vaccination or immunisation involves the use of a photosensitizing agent, a melanoma antigen (i.e. an antigenic molecule), for example a vaccine component, and irradiation with light of a wavelength effective to activate the photosensitizing agent. The invention also relates to said photosensitizing agent and melanoma antigen for use in such a method, and to cells produced by the method.
