Investigate the gene expression profiles of oral sublingual DC and macrophage subsets

Oral mucosa has a potential to maintain immunological homeostasis since little severe inflammation happens in the continuous antigen exposure in the oral cavity. SLIT applied for the allergen-specific immune suppression is performed by repeated antigen (Rpt Ag)-painting to sublingual mucosa (SLM). Among a series of immune cells at submucosa, heterogeneous DC/MF subsets contribute to the orchestration of mucosal immune responses. Previously, We found that Rpt Ag-painting to SLM exhausted typical CD11c+ DCs and induced round-type Macrophage-like CD206hi cells. In this study, we defined three major DC/Macrophage fraction in SLM after Rpt Ag-painting by the expressions of several surface molecules. Fraction 1 (Fr-1): CD206- CD11c+ F4/80lo; Fraction 2 (Fr-2): CD206- CD11c- F4/80+ and Fraction 3 (Fr-3): CD206hi CD11clo F4/80+. Microarray analyses revealed that total of 7282 up-regulated and 7389 down-regulated genes in Fr-3 were enriched compared with Fr-2, respectively. Genes in Fr-3 preferentially expressed molecules related to homeostatic process and negative regulation of T cell activation. Furthermore, new B7 family of immune checkpoint molecules express significantly higher on Fr-3. When we checked the expressions of genes related to M2 MF, Fr-3 cells preferentially express fizz1, aldh1a1 and aldh1a2 but not Ym-1 and arginase-1 compared to in vivo induced M2-like cells. These results indicate that Fr-3 has distinct features compared with M2 like cells and may has T cell regulation potential. Functional investigation imply that CD206hi cell dominant status induces suppression of Ag-specific T cell responses. In conclusion, these results suggest that CD206hi cells from SLM involved in immune tolerogenic inducement by expressing new B7 family molecules and modulate T cell immune responses. 6 Samples were sequenced: Fr-1, Fr-2 and Fr-3 cells were sorted from sublingual mucosa (SLM) of BALB/c mice painted FITC twice to SLM.(n=2 replicates per fraction from independent experiments.)