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: Microbiology
[{'content': 'Salivary protein, which prevents transmission of human immunodeficiency virus via saliva is: \nSelect and explain. \nA. Sialoperoxidase, B. Secretory IgA, C. Salivary leukocyte proteinase inhibitor, D. Histidine rich proteins', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Secretory leukocyte protease inhibitor (SLPI) is found in human saliva, nasal secretions, tears, cervical mucus and seminal fluid. It is believed to be responsible for the anti-HIV properties of external secretions.', 'role': 'assistant'}]