The invention provides immunostimulatory compositions and methods of administration thereof. Also provided are methods of administering a tryptanthrin compound in an effective amount to enhance the immune response of a subject to an antigen. Also provided are methods of administering an effective amount of a tryptanthrin to stimulate the immune response in a subject for the treatment of cancer. Further provided are methods of administering a tryptanthrin compounds as an immunotherapeutic in the treatment of infectious diseases.
