Acute Radiation Syndrome (ARS) is an acute illness caused by irradiation of the entire body (or most of the body) by a high dose of penetrating radiation in a very short period of time. Global proliferation of radioactive and nuclear materials has resulted in increased threat of weaponized exposure or inadvertent exposure resulting from accidents such as Chernobyl. Presence of nuclear weapons within hostile nations combined with continued prospects of US involvement in geo-political conflicts around the world presents a real threat of ionizing radiation exposure to US Defense service personnel. It is imperative that the DOD be prepared with necessary countermeasures. A good medical countermeasure for large-scale, radiological exposure contingencies should ideally be easy to handle and to administer, stable under extreme conditions, thermoresistant, inexpensive, deployable, and must meet medical needs and therapeutic support. The medical countermeasures for ARS are broadly categorized into three classes based on the time of administration in relation to radiation exposure: radioprotectors, radiomitigators, and radiation therapeutics. While there are three FDA-approved post-exposure therapeutic drugs to treat the hematopoietic subsyndrome of ARS, there are no radioprotectors currently approved by the FDA for general human use for the prevention of ARS. We proposal a novel biologic as a radiprotector. Chemically synthesized analog of the biologic materials has demonstrated performance as a radioprotector in murine models. However, it is known that the synthetic analogs are at the most sixty percent as effective as their natural counterparts. We will produce biologically identical materials in their natural form thereby substantially improving the performance. Techno-ecoomic feasibility will be demonstrated during phase I. The work in phase II and beyond will focus on advanced animal models, GLP and GMP process development, and performing necessary tasks towards FDA IND and subsequent NDA application.