Consider the reconstitute and/or dilution method according to your application. There are total of 595 references listed in the datasheet under different applications.
Yes, you may reconstitute human recombinant IFN-gamma in distilled water to a concentration of 100ug/ml. After you have reconstituted, you may use aqueous buffer containing carrier protein such as 1%BSA to further dilute recombinant IFN-gamma.