The invention relates to compositions, methods and uses of inhibitors of binding between PKC&thetas and CD28, and modulating an undesirable or aberrant immune response, disorder or disease, an inflammatory response, disorder or disease, inflammation or an autoimmune response, disorder or disease. Compositions include inhibitors of binding between PKC&thetas and CD28, which include, among others, PKC&thetas, CD28 and Lck sequences, subsequences, variants and modified forms, and polymorphisms.