Immunohistological analysis of CD1 and NKT cells in periodontitis

Objectives: Increasing evidence suggests that immune response to lipid antigens play a crucial role in host defense and the maintenance of tolerance. These responses are mediated by CD1 molecules on antigen-presenting cells and self- and foreign-antigen reactive T cells. Considering the periodontitis having some autoimmune aspect in nature, self-antigen-presenting CD1d and reactive natural killer T (NKT) cells are of particular importance. Therefore the aim of the present study was to examine the expression of CD1 isoforms and Va24+ invariant NKT cells. Methods: Immunohistochemical analysis was performed on cryostat sections of gingival tissues from patients with periodontitis and gingivitis using antibodies to CD1 a,b,c,d, Va24+invariant NKT cells, CD83, CD3 and CD19. Results: Although the cells expressing all four isoforms of CD1 was present, the number of CD1d-expressing cells was most abundant. CD1d expression was more frequent in periodontitis than gingivitis and co-localized with CD19 expression. More invariant NKT cells were observed in periodontitis lesions than gingivitis. Double Immunohistochemical staining showed proximity between NKT cells and CD1d+ cells. Conclusion: These findings suggest that CD1d-expressing B cells and CD1d-restricted NKT cells may be important in antimicrobial immune responses and preventing autoimmune response. This work was supported by Grant-in Aids for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology of Japan (16390613, 16592066).