A method of vaccination or immunisation involving the use of a photosensitizing agent, an antigenic molecule, e.g. a vaccine component, and an agent which enhances the effect of photochemical internalization (PCI)-mediated vaccination is disclosed wherein the agent is a ligand for a Toll-like receptor (TLR), and irradiation is with light of a wavelength effective to activate the photosensitizing agent. Antigenic, e.g. vaccine compositions, useful in such a method are also disclosed along with a method of generating antigen presenting cells which may be used to generate an immune response based on introducing antigenic molecules, e.g. vaccine components, into cells to achieve antigen presentation. The invention also provides methods of achieving vaccination in a subject using such cells.
