A better understanding of the potent immune responses elicited by HIV before infected patients become immunocompromised should enable therapeutic immunomodulation to prevent disease progression. We review the nature of the immune response in HIV infected long-term nonprogressor patients; how and why the immune system fails; and whether it may be feasible to harness the immune system to control viraemia and extend the asymptomatic period in HIV infected persons. Finally we discuss the possibility of inducing sterilizing immunity to enable the host to rid itself of the virus.