2018 Volume 68 Issue 3 Pages 137-144
Hinokitiol (HNK) is a well-known antimicrobial and antifungal agent, and is widely used in various formulations including tooth pastes, mouth rinses, aromatics, cosmetics, and food. There is limited information on the immunobiological activity of HNK. In the present study, we investigated the effects of interanasally administered HNK on salivary secretory-IgA antibody (SIgA Ab) secretion in mice. BALB/c (8 weeks old) mice were given 50 μg of HNK four times at weekly intervals (Days 0, 7, 14, and 21) via the nasal route. Saliva samples were collected prior to (−0 hour) and after (0.5, 1.5, 3, and 6 hours) the nasal administration of HNK on respective days, and the levels of salivary SIgA Ab were determined by ELISA. Furthermore, the numbers of SIgA Ab-producing cells (SIgA AFCs) in submandibular glands (SMG) were examined by ELISPOT, and proliferation responses of IgA+ B cells were measured by MTT assays based on the same schedule on Day 21.
On Days 0, 7, 14, and 21, the maximum level of SIgA Ab secretion in saliva occurred at 1.5 hours after the nasal administration of HNK. Interestingly, the number of doses of HNK and quantities of SIgA secretion showed a positive correlation. On Day 21, there were no significant differences between the number of SMG IgA AFCs prior to and after (0.5, 1.5, 3, and 6 hours) the nasal administration of HNK. However, significantly increased levels of IgA AFCs due to promotion of their proliferative activity were noted 0.5 and 1.5 hours after the nasal administration of HNK. Our results suggest that HNK has an impact on salivary SIgA Ab secretion immediately after nasal administration via elevating the proliferative activity of SMG IgA AFCs.
