Salivary Immunology — MFDS Part 1 MCQ
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Correct answer: E — Secretory IgA
Secretory IgA is the predominant immunoglobulin in saliva. It is produced locally by plasma cells as polymeric, usually dimeric, IgA and transported through salivary-gland epithelium with a secretory component. It contributes to mucosal immune exclusion by neutralising pathogens and reducing their adherence to oral surfaces. IgG is also present and may increase with gingival inflammation, but much of it reaches saliva through gingival crevicular fluid and it does not normally predominate. Secretory IgM occurs in smaller amounts, while IgE and IgD are only minor salivary immunoglobulins. Therefore, A is the single best answer.
Reference: Pettersson L et al. Hantavirus-specific IgA in saliva and viral antigen in the parotid gland in patients with hemorrhagic fever with renal syndrome. Journal of Medical Virology. 2011;83(5):864–870. https://pubmed.ncbi.nlm.nih.gov/23487566/