The present invention is drawn to compositions and methods to enhance an immune response in order to prevent or treat infections or hyperproliferative diseases such as cancer. More particularly, the composition is an immunostimulatory intracellular signaling peptide fused directly or indirectly to a peptide that leads to multimerization into complexes of three or more units, where the intracellular signaling peptide must be present in a complex of three or more units in order to stimulate an immune response. Inserting this fusion construct into viruses like HIV-1 or introducing it into dendritic cells or tumor cells is predicted to lead to a positive therapeutic effect in humans, non-human mammals, birds, and fish.