Abstract: Methods of treating and preventing radiation injury are provided by the present invention. In particular, provided herein are methods comprising administering to a subject an Activated Protein C (APC), Plasma Zymogen Protein C (PC), or a variant thereof to treat or prevent radiation injury and to reduce chemical toxicity in subjects receiving myelosuppressive therapy.

Abstract: Recombinant activated protein C (APC) and APC variants with reduced anticoagulant activity were used to reduce mortality in murine models of sepsis. These models included endotoxemia and bacteremia models. We discovered that single or multiple bolus doses of APC, especially of APC variants such as RR230/231AA-APC, KKK192-194AAA-APC and 5A-APC (containing the combination of mutations present in the first two APC variants) given as a single bolus reduces 7-day mortality of mice given lethal doses of endotoxin. Administrations of a single bolus of 5A-APC after the initiation of sepsis also reduces mortality caused by LPS. 5A-APC with ?8% of normal anticoagulant activity (which has reduced risk of bleeding) reduces mortality when given as two bolus administrations at 3 hours and then at 10 hours after initiation of bacterial infection, i.e. after onset of sepsis.

Abstract: A method of treating a disease is disclosed. In one embodiment, the method comprises administering to a patient an effective amount of factor V protein or fragment of factor V protein, wherein the amount of protein is sufficient to alleviate or prevent disease symptoms and wherein the protein is resistant to inactivation by APC.