The invention provides a method of preventing or reducing the severity of acancer in a subject by stimulating the subject's immune response against thecancer. The invention provides, for example, a method of stimulating an immuneresponse in a subject by administering to the subject tumor cells that aresubstantially similar to the subject's cancer cells and that are geneticallymodified to reduce or inhibit the expression of one or more immunosuppressiveagents. The invention also provides a method of preventing or reducing theseverity of cancer in a subjet by stimulating the subject's immune responseagainst the cancer by administering to the subject tumor cells that aresubstantially similar to the subject's cancer cells and that are geneticallymodified to prevent the expression of an immunosuppressive agent and, incombination with the genetically modified tumor cells, an immunostimulatoryagent. The invention further provides compositions useful for practicing theclaimed methods.
