1. Acute myocardial infarction with ST elevation at the J-point in two contiguous leads as determined by ECG. 2. TIMI grade 0 (no flow) or grade 1 (penetration without perfusion) of the culprit artery on initial coronary angiogram 3. Symptom onset prior to PCI of ≤12 hours 4. Planned to receive the local standard of care for treatment of their STEMI and follow up which must include percutaneous coronary intervention (PCI) 5. Ability to infuse study drug within 12 hours of PCI 6. Age ≥18 years, willing and able to provide written informed consent and to comply with the protocol (i.e., reporting of symptoms) 7. Capable of completing study visits 8. Females participating in the study must meet one of the following criteria: 1. Postmenopausal (postmenopausal females must have no menstrual bleeding for at least 1 year); 2. Surgically sterilized (e.g., hysterectomy, bilateral oophorectomy, or tubal ligation) for at least 6 months; or 3. If not postmenopausal, agree to use a double method of contraception, one of which is a barrier method (e.g., intrauterine device plus condom, spermicidal gel plus condom) until 30 days after the treatment 9. Males who have not had a vasectomy must use appropriate contraception methods (barrier or abstinence) until 30 days after treatment

An individual fulfilling any of the following criteria is to be excluded from enrollment in the study: 1. Killip Classification for Heart Failure Class III (acute pulmonary edema) or IV (cardiogenic shock) 2. Severe aortic or mitral valve disease 3. Failure to reperfuse, vascular dissection, cardiac perforation, cardiac arrest, requirement for mechanical circulatory support, or acute respiratory failure requiring ventilatory support 4. Major hemodynamic instability or uncontrolled ventricular arrhythmias 5. Planned or conducted thrombolytic therapy for treatment of this STEMI event 6. Planned or conducted coronary artery bypass graft 7. Previous major vascular intervention within the last 4 weeks 8. Major surgery within the last 6 weeks 9. Evidence of an active gastrointestinal or urogenital bleeding 10. Recent (<14 days) use of immunosuppressive or anti-inflammatory drugs (including oral corticosteroids at a prednisone equivalent dose of ≥0.5 mg/kg/day but not including inhaled or low-dose oral corticosteroids, non-steroidal anti-inflammatory drugs, or colchicine). 11. Chronic inflammatory disorder (i.e., rheumatoid arthritis, systemic lupus erythematosus). 12. Active infection (of any type), including chronic/recurrent infectious disease (including HBV, HCV, and HIV/AIDS), but excluding HCV+ with undetectable plasma RNA. 13. Neutropenia (<1,500/mm3 or <1,000/mm3 in Black/African American patients). 14. Active malignancy, excluding carcinoma in situ [any location] or localized non-melanoma skin cancer 15. Participation in any study using an investigational drug or device within 30 days or within 5 half-lives of the investigational drug (whichever is longer) of entry into this study. 16. Life expectancy of less than 1 year due to non-cardiac pathology 17. History of allergic reaction to atibuclimab (IC14), any monoclonal antibody, or any other component used in the study (including contrast media) 18. Body weight >300 pounds (weight limit of the PET/CT table) 19. Known severe renal (creatinine clearance <30 mL/min) or hepatic insufficiency as well as alanine transaminase (ALT) elevation ≥ 3x upper limit of normal; isolated AST-elevation is not considered an exclusion criterion from study participation 20. Any clinically significant abnormality identified at the time of Screening that in the judgment of the Investigator, or any sub-Investigator would preclude safe completion of the study