Salivary gland immunization via Wharton’s duct activates differential T-cell responses within the salivary gland immune system

What is it about?

Salivary glands are a major component of the mucosal immune system that confers antigen-specific immunity to oral and mucosally acquired pathogens. Because of the importance of salivary gland function to oral health, a better understanding of the biology of the salivary gland from the perspective of limiting pathologies and for the induction of protective immune responses are necessary. Since mucosal surfaces of the body are a significant portal of entry for many pathogens, especially viruses, understanding the mechanisms of defense in these tissues is important in vaccine development especially for pathogens that enter through mucosal sites such as the oral cavity. Mucosally administered vaccines are of interest not only because of their ease of administration and lack of discomfort, but also their ability to protect at multiple mucosal sites as well as systemic sites. We report salivary gland inoculation of mice with the viral pathogen, MCMV, differentially activates helper T cells in the salivary glands versus the associated lymph nodes. After inoculation with MCMV, lymphocytes from the submandibular gland preferentially activate Th1 helper cells, while associated lymph nodes activate both Th1 and Th2 cells. After inoculation with replication-deficient adenoviruses expressing genes of MCMV, only lymphocytes from the submandibular gland are activated and express Th1, Th2, Treg, and Th17 helper T cells. This differential induction of TH responses in the salivary gland versus the lymph nodes supports the use of the salivary as an alternative mucosal route for administering vaccines, which is directly applicable for use in humans.

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