Provided is a method for enhancing an immune response to a desired antigen in an individual. The method is performed by administering to the individual an agent capable of inhibiting class A macrophage scavenger receptor (SR-A) and optionally administering the desired antigen. Also provided is a method for enhancing an immune response to an antigen by administering to an individual a composition containing antigen presenting cells that are characterized by specifically inhibited SR-A. Substantially purified populations of mammalian dendritic cells characterized by specifically inhibited SR-A are also provided.