Dendritic Cells at the Oral Mucosal Interface

Abstract

The mucosal lining of the respiratory and digestive systems contains the largest and most complex immune system in the body, but surprisingly little is known of the immune system that serves the oral mucosa. This review focuses on dendritic cells, particularly powerful arbiters of immunity, in response to antigens of microbial or tumor origin, but also of tolerance to self-antigens and commensal microbes. Although first discovered in 1868, the epidermal dendritic Langerhans cells remained enigmatic for over a century, until they were identified as the most peripheral outpost of the immune system. Investigators' ability to isolate, enrich, and culture dendritic cells has led to an explosion in the field. Presented herein is a review of dendritic cell history, ontogeny, function, and phenotype, and the role of different dendritic cell subsets in the oral mucosa and its diseases. Particular emphasis is placed on the mechanisms of recognition and capture of microbes by dendritic cells. Also emphasized is how dendritic cells may regulate immunity/tolerance in response to oral microbes.

Pacifier Cleaning Practices and Risk of Allergy Development

“…Bacterial DNA was extracted from 150 mL saliva (QIAamp DNA Stool Mini Kit; Qiagen, Hildens, Germany) according to the manufacturer' s instructions, but included shaking (1200 rpm) with 2-mm glass beads (10-12 beads/ sample) for 30 minutes at 5°C after addition of the ASL buffer. Extracted DNA, 50 ng as measured by spectrophotometry (version 3.3; NanoDrop Technologies, Wilmington, DE), was mixed with 0.3 mM of the 16S rRNA universal primers ENV1 (59-6-FAM-AGA GTT TGA TII TGG CTC AG -39; Escherichia coli 16S rRNA gene sequence nucleotide positions [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] and ENV 2 (59-CGG ITA CCT TGT TAC GAC TT-39; E coli 16S rRNA gene sequence nucleotide positions 1511-1492), 25 mL Hot Start Taq Master Mix (2.5 U Taq DNA polymerase, 1.5 mM MgCl 2 , 200 mM dNTP) (Qiagen), 1 mM MgCl 2 , and water to a final volume of 50 mL. The ENV1 primer was labeled with 6-FAM fluorescent dye.…”

“…Similar to the gut-associated lymphoid tissues, these are covered by M-cells that are specialized in antigen uptake and delivery to antigen-presenting cells and lymphocytes beneath the epithelium. 27 Furthermore, dendritic cells capture antigens in the oral mucosa and migrate to cervico-mandibular lymph nodes, 28 similar to the way dietary antigens are carried to the mesenteric lymph nodes. The tonsils are rich in T cells with a regulatory phenotype, 29 …”

Potential immunological functions of salivary Hsp70 in mucosal and periodontal defense mechanisms

“…Langerhans and dendritic cell [23]) and there is also a considerable flux of neutrophils through the gingival sulcus into saliva even in health. Regarding these, an important potential function of salivary Hsp70 could be the modulation of antigen sampling, since uncomplexed Hsp70 binds other peptides, and as a complex induces receptor-mediated uptake into antigen-presenting cells [8,10,51,74,75,79].…”

Oral epithelial barrier function and the role of nuclear factor kappa-? pathway in the pathogenesis of aphthous ulceration

“…Pattern recognition receptors are found both on the surface and the inner part of the mucosal epithelial layer and Langerhans cells. The type and location of the activated pattern recognition receptors may determine the severity of the ensuing immuno-inflammatory reaction (1,3).…”