Abstract: The present invention is directed to methods for stimulating primary and secondary effector cell responses for cellular immunotherapy. Cellular immunotherapy can successfully prevent or treat various viral infections and tumors, such as posttransplant EBV lymphoma. The present invention offers a general method for effecting cellular immunotherapy by providing for presentation, by the most effective antigen presenting cells, viral particles or specific antigens, without the need to develop an active viral infection in the antigen presenting cells. Furthermore, the present invention provides for generating effector cells against more than one opportunistic pathogen, e.g., Epstein-Barr virus and adenovirus. The effector cells generated according to the invention, which include CD4 and CD8 cells, are extremely long lived in vivo after adoptive transfer.