A 40-year-old male, who was in good health earlier, begins experiencing a chronic cough. Over the following 6 weeks, the cough gradually worsens and becomes productive. He is also coughing up blood, and notes weight loss, fever, and night sweats. A sputum sample is positive for acid-fast bacilli. Which of the following pathogenic mechanisms can be primarily attributed to the etiologic agent involved in this disease?