Retrograde access of antigens to the minor salivary glands in the monkey Macaca fascicularis.

Several authors have postulated that the ducts of minor salivary glands may provide pathways for the presentation of oral antigens to cells involved in a local immune response. This would imply a retrograde passage of oral antigens into the minor salivary glands. Various sites of the oral mucosa of anaesthesized M. fascicularis monkeys were labelled topically with a multiple tracer consisting of horseradish peroxidase (HRP), ferritin and Indian ink for a continuous period of 4-5 h. Serial cryosectioning of labelled lips and soft palates revealed retrograde passage of this tracer deep into some of the corresponding minor salivary glands. Minor salivary gland ducts can therefore serve as "portal of entry" for oral antigens, at least in the M. fascicularis monkey.