Methods of inducing T cell proliferation and expansion in vivo for treating conditions wherein antigen-specific T cell immune response are therapeutically desirable such as cancer, infection, inflammation, allergy and autoimmunity and for enhancing the efficacy of vaccines are provided. These methods comprise the administration of at least one CD27 agonist, preferably an agonistic CD27 antibody, alone or in association with another moiety such as immune stimulant or immune modulator such as an anti-CD40, OX-40, 4- IBB, or CTLA-4 antibody or an agent that depletes regulatory cells, or a cytokine. These mono and combination therapies may also optionally include the administration of a desired antigen such as a tumor antigen, an allergen, an autoantigen, or an antigen specific to an infectious agent or pathogen against which a T cell response (often CD8+) is desirably elicited.
