Eligibility Criteria- INCLUSION CRITERIA:
Adult male or female patients with confirmed acute ischemic stroke, presenting within 24 hours of symptom onset and meeting inclusion criteria at each of the study sites will be assessed for possible enrollment into the study.
1. New focal neurologic deficit consistent with acute cerebral ischemia.
2. Age greater than or equal to 18 and less than or equal to 85.
3. Premorbid modified Rankin score 0-2 (functionally independent).
4. Signed informed consent obtained from the patient or patient's legally authorized representative.
5. Initiation of study drug within 24 hours of symptom onset.
1. Acute intracerebral hemorrhage.
2. Major surgery planned within 30 days of symptom onset.
3. Treatment with IV tPA or other recanalization therapy for current event.
4. Pre-existing medical, neurological or psychiatric disease that would confound the outcome evaluations.
5. Women known to be pregnant, lactating or having a positive or indeterminate pregnancy test.
6. Coma or altered level of consciousness (score of 1 or more on LOC items of NIHSS score).
7. Hemodynamic instability.
8. Current participation in another experimental treatment protocol.
9. Inadequate liver function, defined by a total bilirubin, AST or ALT or alkaline phosphatase greater than 2 times the upper limit of normal values.
10. Renal impairment with serum creatinine greater than 2.0 mg/dl.
11. NIHSS greater than 18.
12. Prior use of interferon.
13. Active major infection.
14. Allergy to human serum albumin, mannitol.
15. Seizure disorder or seizure at onset of stroke.
16. Severe depressive disorder and/or suicidal ideation.
17. Significant leukopenia (white blood cell count less than 0.5 times the lower limit of normal) within 7 days prior to symptom onset.