In the past, adoptive immunotherapy often failed because the transferred immune cells were inactive in vivo. This disclosure provides a method of producing immune cells that are highly active in vivo. The immune cells may be expanded in vitro in the presence of an adenosine receptor agonist or an antisense nucleic acid that downregulates expression of an adenosine receptor, for example. The immune cells may be tumor-infiltrating lymphocytes (TIL), cytotoxic T lymphocytes (CTL), natural killer (NK) cells, or lymphokine-activated killer (LAK) cells, for example. The methods described herein may be used to treat a number of diseases including cancer, infectious diseases, and immunodeficiencies.
