This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
[{'content': 'Phagocytosis of TB bacilli does not occur because of- \nSelect and explain. \nA. Wax D, B. Muramyl dipeptide, C. Cord factor, D. Peritrichate Cilia', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans. is \'c\' i.e., Cord factor o Virulent strains of tubercle bacilli form microscopic "serpentine cord" in which acid fast bacilli are arranged in parallel chains, cord formation is correlated with virulence. A "cord factor" has been extracted from virulent bacilli with pateroleum ether. It inhibits migration of leukocytes, causes chronic granulomas, and can serve as an immunologic "adjuvant".', 'role': 'assistant'}]