This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacteria, Subject name: Microbiology
[{'content': 'Which of the following is not an AB 5 toxin- \nSelect and explain. \nA. Cholera toxin, B. Pertussis toxin, C. Shiga toxin, D. Heat labile toxin', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. B. Pertussis toxin.a. Pertussis toxin is a 105 kDa protein composed of six subunits:b. S1 (A subunit) and B subunit consisting of S2, S3, (2) S4, and S5.c. Pertussis toxin is the most important virulence factor- helps it to evade phagocytes by inhibiting their phagocytic function and helps the bacterium to bind host cells.', 'role': 'assistant'}]