The present invention is directed to a method for promoting or stimulating a cell-mediated immune response to an antigen, by administering a target antigen (such as a protein) with a transport factor that contains a fragment of a bipartite protein exotoxin, but not the corresponding protective antigen. Preferred transport factors include the protective antigen binding domain of lethal factor (LFn) from B. anthracis, consisting of amino acids 1-255, preferably a fragment of at least 80 amino acids that shows at least 80% homology to LFn, and a fragment of about 105 amino acids from the carboxy portion that does not bind PA. The target antigen can include any molecule for which it would be desirable to elicit a CMI response, including viral antigens and tumor antigens.