Review Question - QID 109623

A 45-year-old male presents to his primary care provider for a normal check-up. The patient emigrated from a rural region of Indonesia one year ago. He is accompanied by his son who reports that the patient has never seen a physician. The patient does not drink or smoke. His temperature is 98.6°F (37°C), blood pressure is 130/75 mmHg, pulse is 90/min, and respirations are 18/min. A notable physical examination finding is shown in Figure A, and it is numb to palpation. A biopsy of one of these lesions is performed, revealing epithelioid histiocytes and abundant lymphocytes. Acid-fast bacilli are noted. Which of the following is produced by the immune cells responsible for the activation of epithelioid histiocytes in this condition?