Cytokine regulation of major histocompatibility complex antigen expression by human oral and skin keratinocytes

An Unusual Case of Maxillary Sinus Odontogenic Keratocyst: An Insightful Report With Review of the Literature

Maxillary sinus odontogenic keratocyst (OKC) is very rare and occupies less than 1% of the total OKC cases reported in the literature. OKCs have characteristic features that are unique compared to other cysts of the maxillofacial region. Considering their peculiar behaviour, varied origin, debated development, discourse treatment modalities, and high recurrence rate, OKCs have been a subject of interest for various oral surgeons and pathologists globally. This case report presents an unusual case of invasive maxillary sinus OKC into the orbital floor, pterygoid plates, and hard palate in a 30-year-old female. The case report confers that cystic maxillary sinus lesions should always be treated very extensively irrespective of the nature of the lesion as the site makes it highly susceptible to secondary infection and recurrence. The case also establishes a set of imaging modalities and specific treatment approaches to be followed for maxillary sinus OKC based on the literature of all the previous cases reported.

Immune mechanisms in oral lichen planus

Oral lichen planus (OLP) is a T-cell-mediated inflammatory disease of the oral mucosa that has been extensively researched over many years but as yet the mechanisms of pathogenesis are still not fully understood. Whilst the specific etiologic factors driving OLP remain ambiguous, evidence points to the development of a chronic, dysregulated immune response to OLP-mediating antigens presented by innate immune cells and oral keratinocytes leading to increased cytokine, chemokine and adhesion molecule expression. These molecules recruit T-cells and mast cells to the diseased site and orchestrate a complex interplay between cells that culminates in keratinocyte cell death, mucosal basement membrane destruction and long-term chronicity of the disease. The main lymphocytes involved are thought to be CD8+ cytotoxic and CD4+ Th1 polarised T-cells although recent evidence indicates the involvement of other Th subsets such as Th9, Th17 and Tregs, suggesting that a more complex immune cell relationship exists during the disease process. This review provides an overview of the immune mechanisms at play in OLP pathogenesis with particular emphasis on the role of the different Th subsets and how these recent discoveries may guide research toward identifying potential therapeutic targets.

The presence of bacteria within tissue provides insights into the pathogenesis of oral lichen planus

Oral lichen planus (OLP) is a chronic T cell-mediated mucocutaneous disease of unknown etiopathogenesis. Although various antigens have been considered, what actually triggers the inflammatory response of T cells is unknown. In the present study, we propose that intracellular bacteria present within tissues trigger T cell infiltration and provide target antigens. Sections of OLP (n = 36) and normal (n = 10) oral mucosal tissues were subjected to in situ hybridization using a universal probe targeting the bacterial 16S rRNA gene and immunohistochemistry with anti-CD3, anti-CD4, anti-CD8, and anti-macrophage-specific antibodies. Bacteria were abundant throughout the epithelium and the lamina propria of OLP tissues, which exhibited positive correlations with the levels of infiltrated CD3(+), CD4(+), and CD8(+) cells. Furthermore, bacteria were detected within the infiltrated T cells. Pyrosequencing analysis of the mucosal microbiota from OLP patients (n = 13) and control subjects (n = 11) revealed a decrease in Streptococcus and increases in gingivitis/periodontitis-associated bacteria in OLP lesions. Using the selected bacterial species, we demonstrated that certain oral bacteria damage the epithelial physical barrier, are internalized into epithelial cells or T cells, and induce production of T cell chemokines CXCL10 and CCL5. Our findings provide insights into the pathogenesis of OLP.

Enteroglial cells act as antigen-presenting cells in chagasic megacolon

Chagas disease is one of the most serious parasitic diseases of Latin America, with a social and economic impact far outweighing the combined effects of other parasitic diseases such as malaria, leishmaniasis, and schistosomiasis. In the chronic phase of this disease, the destruction of enteric nervous system components leads to megacolon development. Besides neurons, the enteric nervous system is constituted by enteric glial cells, representing an extensive but relatively poorly described population within the gastrointestinal tract. Several lines of evidence suggest that enteric glial cells represent an equivalent of central nervous system astrocytes. Previous data suggest that enteric glia and neurons are active in the enteric nervous system during intestinal inflammatory and immune responses. To evaluate whether these cells act as antigen-presenting cells, we investigated the expression of molecules responsible for activation of T cells, such as HLA-DR complex class II and costimulatory molecules (CD80 and CD86), by neurons and enteric glial cells. Our results indicate that only enteric glial cells of chagasic patients with megacolon express HLA-DR complex class II and costimulatory molecules, and hence they present the attributes necessary to act as antigen-presenting cells.

Transfection of CD40 in a human oral squamous cell carcinoma keratinocyte line upregulates immune potency and costimulatory molecules

BACKGROUND

There is upregulation of class II molecules of the major histocompatibility complex (MHC) by keratinocytes in oral squamous cell carcinoma (OSCC) and inflammatory diseases such as lichen planus. The significance of this expression, or whether it is accompanied by upregulation of membrane-bound costimulatory molecules, is unknown.

OBJECTIVES

To compare the expression of CD40, CD80, CD86, MHC class II and intercellular adhesion molecule-1 (ICAM-1), and the ability to induce allogeneic T-lymphocyte proliferation in vitro, of a CD40- OSCC cell line, its CD40+ transfected derivative and null transfectants.

METHODS

OSCC cell lines and purified T lymphocytes were cocultured and T cell proliferation recorded. Phenotypes were analysed by flow cytometry.

RESULTS

After T lymphocyte proliferation, which all OSCC cell lines were able to induce, there was upregulation of MHC class II and ICAM-1. However, the CD40+ transfectants were the most immunologically potent and were the only cells to show increased expression of CD86 (as well as further upregulation of CD40 and a statistically insignificant rise in CD80). The effects of blocking antibodies on T-cell proliferation were only statistically significant with the CD40+ transfectants.

CONCLUSIONS

While not essential, expression of CD40 by OSCC cells is necessary for optimal induction of allogeneic T lymphocytes, possibly because of concurrent upregulation of other membrane-bound costimulatory molecules.

Adrenomedullin expression by gastric epithelial cells in response to infection

Many surface epithelial cells express adrenomedullin, a multifunctional peptide found in a wide number of body and cell systems. Recently, we and others have proposed that adrenomedullin has an important novel role in host defense. This peptide has many properties in common with other cationic antimicrobial peptides, including the human beta-defensins. Upon exposure of human gastric epithelial cells to viable cells of invasive or noninvasive strains of Helicobacter pylori, Escherichia coli, Salmonella enterica, or Streptococcus bovis, a significant increase in adrenomedullin secretion from these cells was demonstrated. Adrenomedullin gene expression was also increased in response to these microorganisms. Similar observations were noted when these cells were incubated with proinflammatory cytokines such as interleukin 1 alpha (IL-1 alpha), IL-6, tumor necrosis factor alpha and lipopolysaccharide. In cultured cells and an animal infection model, increased adrenomedullin peptide and gene expression was demonstrated when exposed to E. coli or Mycobacterium paratuberculosis, respectively. The data suggest there is a strong association between epithelial infection, inflammation, and adrenomedullin expression, which may have clinical relevance. The regulation of adrenomedullin expression may have therapeutic applications, such as improving or enhancing mucosal immunity.

Adrenomedullin and mucosal defence: interaction between host and microorganism

Many surface epithelial cells express adrenomedullin (AM) and it is postulated that it may have an important protective role. This peptide has many properties in common with other cationic antimicrobial peptides including the human beta-defensins. Antimicrobial activity against members of the human skin, oral, respiratory tract and gastric microflora has been demonstrated. Both pathogenic and commensal strains of bacteria are sensitive; Gram-positive and Gram-negative bacteria being equally susceptible. No activity against the yeast Candida albicans was observed. Minimum inhibitory and minimum bacteriocidal concentrations range from 7.75 x 10(-4) to 12.5 and 0.003 to >25.0 microg ml(-1), respectively. On exposure of oral, skin and gastric epithelial cells to whole cells and culture supernatants from bacteria isolated from these sites an increase in AM peptide and gene expression has been observed. No upregulation was detected with C. albicans. In cultured cells and an animal infection model increased AM peptide and gene expression has been demonstrated using immunohistochemical and in situ hybridization techniques. These collective findings suggest that AM represents a new category of antimicrobial peptide, which contributes to the mucosal host defence system.

In vitro and in vivo regulation by macrophage migration inhibitory factor (MIF) of expression of MHC-II, costimulatory, adhesion, receptor, and cytokine molecules

The secretion of macrophage migration inhibitory factor (MIF) is enhanced by inflammatory and other stimuli. MIF regulates innate and adaptive immune responses, but the mechanisms of this regulation are poorly understood. Our hypothesis was that MIF generated by these stimuli regulates these responses by modulating key molecular expression. This hypothesis was tested by adding greater than constitutive concentrations of recombinant MIF to cultures of various cell types and flow cytometric assay. MIF modulated surface expression of MHC-II, B7-2, CD40, CD40 ligand, ICAM-1 and Fcgamma, CR1/CR2, and IL-10 receptors and intracellular expression of IL-10, TNFalpha, and p40 (IL-12). MIF increased expression of B7-1 by B cells and CD40 L by T cells in spleens from Schistosoma mansoni-infected mice. Footpad injection of MIF reduced expression of MHC-II and CD40 by B cells in draining lymph nodes. Footpad injection of Mab to MIF reduced expression of B7-2 and CR1/CR2 by B cells and B7-2 by macrophages in these nodes. These data support our hypothesis.

Adrenomedullin expression in pathogen-challenged oral epithelial cells

Adrenomedullin, a multifunctional peptide, is expressed by many surface epithelial cells and, previously, we have demonstrated that adrenomedullin has antimicrobial activity. The oral cavity contains an epithelium that is permanently colonized by microflora, yet infections in a host are rare. We exposed oral keratinocytes to whole, live cells from four microorganisms commonly isolated from the oral cavity, Porphyromonas gingivalis, Streptococcus mutans, Candida albicans and Eikenella corrodens. There was upregulation of protein and gene expression in these cells in response to bacterial suspensions, but not with the yeast, Candida albicans. We propose there is a potential role for microbial products in enhancing mucosal defense mechanisms and that adrenomedullin participates in the prevention of local infection, thus contributing to host defense mechanisms.

CD9 and HLA-DR expression by crevicular epithelial cells and polymorphonuclear neutrophils in periodontal disease

BACKGROUND, AIMS

The composition of gingival crevicular fluid (GCF) is likely to reflect inflammatory modifications that take place in the gingiva during periodontal diseases.

METHOD

In this study, GCF was collected at 3 different sites from 23 periodontal patients. The sites were assessed to be healthy, presenting gingivitis or periodontitis. 10 healthy individuals without any form of periodontal disease formed the control group and were sampled at one site each. The cell content of GCF was collected using Durapore Millipore strips, and 2 types of cells were studied: epithelial cells (EC) and polymorphonuclear neutrophils (PMN). The expression of CD9 and HLA-DR within or on the surface of these cells was studied in immunofluorescence on cytospin smears.

RESULTS

Both CD9 and HLA-DR expression on EC differed significantly from control subjects, and the latter decreased according to the severity of the pathology. None of the PMN found in controls expressed CD9 or HLA-DR. However, in periodontal patients, the expression of HLA-DR within PMNs was detectable and increased according to the severity of lesions. CD9 expression on PMNs also increased with inflammation.

CONCLUSION

This study shows that clinically healthy sites of periodontal patients already present signs of immunological activation characterised by a down modulation of HLA-DR expression on EC and an upregulation of these 2 molecules in PMN.

Induction of adhesion molecule expression on blood vessels and keratinocytes in recurrent oral ulceration

Adhesion molecules are known to play a crucial role in the recruitment of inflammatory cells to sites of inflammation. In this study endothelial cell and keratinocyte adhesion molecule expression in recurrent oral ulcers (ROU) (n = 13) was compared with that found in normal oral mucosa (NOM) (n = 11) and experimentally induced ulcers (EIU) (n = 5) by using immunohistochemistry. Significantly greater expression of both vascular cell adhesion molecule- (VCAM-1) and E-selectin was demonstrated on vasculature in ROU compared with that found in both NOM and EIU. Induction of keratinocyte intercellular adhesion molecule-1 (ICAM-1) was also a prominent feature of ROU. The expression of VCAM-1 and E-selectin on blood vessels in ROU is likely to be important in the accumulation of lymphocytes that characterise early aphthous lesions. The induction of keratinocyte ICAM-1 may facilitate lymphocyte invasion of the epithelium in ROU, which may ultimately result in ulcer formation.