Compounds, uses and methods for modulating an immune response are provided. In particular, modulating the interaction of PKC&eegr; with CTLA-4 can modulate an immune response. For example, modulating activity or expression of PKC&eegr;, and/or modulating activity or expression of CTLA-4, can be used to modulate interaction of PKC&eegr; with CTLA-4, thereby modulating an immune response.