CTLA-4 blockade in combination with xenogeneic DNA vaccines enhances T-cell responses, tumor immunity and autoimmunity to self antigens in animal and cellular model systems.

Xenogeneic DNA vaccination can elicit tumor immunity through T cell and antibody-dependent effector mechanisms. Blockade of CTLA-4 engagement with B7 expressed on APCs has been shown to enhance T cell-dependent immunity. We investigated whether CTLA-4 blockade could increase T-cell responses and tumor immunity elicited by DNA vaccines.