This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General pathology, Subject name: Pathology
Indirectly cytopathic viruses kill cells by provoking an 
Select and explain. 
A. Injury to DNA, B. Immune response, C. Injury to the cell membrane, D. Influx of potassium
B: Immune response
Answer: B: Immune response 
Explanation: In contrast to directly cytopathic viruses, which cause cell death by damaging the cell membrane indirectly, cytopathic viruses produce antigenic proteins that are inseed into the cell membrane and are capable of evoking an immune response. Attack by immune lymphocytes, which recognize the viral protein as foreign, destroys the cell membrane.