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: Dental
It is likely that cell mediated immune reactions (delayed
hypersensitivity) occur in periodontitis because subjects with periodontitis have 
Select and explain. 
A. High levels of histamine in involved gingival tissue, B. IgG antibodies reactive with plaque bacterial antigens, C. Ttymphocytes sensitized to bacterial plaque antigens, D. High Levels of collagenase in gingival fluids
C: Ttymphocytes sensitized to bacterial plaque antigens
Answer: C: Ttymphocytes sensitized to bacterial plaque antigens 
Explanation: None