Ship inhibition to induce activation of natural killer cells

A method of activating natural killer (NK) cells in a subject suffering from an illness or condition for which NK cells provide a host defense, said method comprising:

• periodically administering a safe and effective amount of a SHIP1 inhibitor to the subject, wherein an administration period is immediately followed by a rest period during which no SHIP1 inhibitor is administered, wherein a cycle of one administration period followed by one rest period is repeated, wherein the administration period has a duration of no less than two days, but no more than three days, and the rest period has a duration of between two and ten days, inclusive, and wherein periodic administration of the SHIP1 inhibitor activates NK cells in the subject.