Which of the following is involved in the host's defense response to periodontal pathogens?

Correct answer: B. Proteases

• A. Incorrect. Mucins are salivary glycoproteins with protective roles but are not the primary defense response against periodontal pathogens.
• B. CORRECT. Proteases — particularly matrix metalloproteinases (MMPs) released by host immune cells — are key mediators of the host defense and tissue destruction in periodontal disease. They degrade the extracellular matrix. Bacterial proteases also evade host defenses. This bidirectional protease activity defines periodontal pathogenesis.
• C. Incorrect. Complement is part of the innate immune response but not the specific answer in this context.
• D. Incorrect. Fibrin is part of the coagulation response but is not the primary direct immune defense mechanism in periodontitis.