Induction of Tolerance via the Sublingual Route: Mechanisms and Applications

Figure 1

Fate of the allergen following sublingual administration. Following sublingual immunization, substantial amounts of the allergen bind to epithelial cells within minutes, then cross the mucosa between 15 and 30 minutes. The allergen is subsequently captured by dendritic cells (likely by Langerhans cells (LCs) within the mucosa itself and myeloid dendritic cells (MDCs) along the lamina propria) and processed as small peptides presented in association with MHC class I and class II molecules at the cell surface. Those DCs loaded with allergen-derived peptides reach cervical lymph nodes within 12 to 24 hours, where they interact with naive CD4⁺ T cells to support the differenciation of Th1 and T Reg cells within two to five days. These CD4⁺ T cells subsequently migrate into the blood and back to mucosal tissues, resulting in allergen tolerance with downregulation of preexisting Th2 responses.