Innate Immune Effector Function

Oral epithelial cells are constantly exposed to microbial challenge and therefore play an important role as the first line of defense against infection. In addition to secretion of natural antibiotic peptides (i.e., calprotectin and defensins) with antifungal Figure 2.1. Yeast and pseudohyphal forms of C. albicans do not injure oral epithelial cells or trigger a proinflammatory cytokine response. SCC15 oral epithelial cells were cocultured with C. albicans SC5314 (wt.), or its congenic yeast...

Gingival Crevicular Fluid

GCF is an inflammatory exudate originating from the leaky venules next to the oral sulcular and junctional epithelia. An increase in the flow rate of GCF has been associated with inflammatory changes in the gingival tissues, secondary to bacterial infection (reviewed in Tonetti et al., 1998). In addition to salivary PMN and macrophages that exude through the oral junctional and sulcular epithelia into the GCF, the GCF also contains relatively high levels of Table 2.1. Oral Innate Effector...

Histopathologic Characteristics

Chronic hyperplastic or pseudomembra-nous candidiasis is a form of infection with distinct clinical and histopathological characteristics. The histologic features of this infection include a hyperplastic and parak-eratotic response of the surface epithelium, which is invaded by hyphal organisms. The inflammatory infiltrate consists primarily of PMN, which form microabscesses within the epithelium, whereas very few PMN are found within the lamina propria in association with blood vessels...

Oral Microbial Ecology

The oral mucosa is colonized by over 200 microbial species. Thus, the potential for bacterial and fungal infections is high, with a need for innate defense mechanisms. The oral cavity is comprised of at least four microbial ecological niches with a certain degree of variability in the composition of their indigenous flora the saliva, the tongue, and the tooth-associated supragingival and subgingival plaques (Slots, 1992). The most predominant indigenous bacterial flora in saliva, tongue and...

Salivary IgA Subclass Antibodies to Candida

IgA subclass antibodies have been reported in a few studies in patients with CAC. IgA antibodies and IgA1 antibodies were increased in comparison with the controls (Ivanyi and Ivanyi, 1990). However, it is possible that some of this IgA1 antibody might have been derived from inflammation in the oral cavity itself. However, Coogan et al. (1994) showed that in HIV infection IgA1 and IgA2 subclass antibodies against Candida were raised in both whole and parotid saliva compared with controls. This...

Humoral Immunity against Oral Candidiasis

A variety of studies have attempted to address the question of whether antibodies might be protective, in which case they might be expected to be higher in controls than in patients, or whether antibodies might reflect the antigenic load in which case they would be expected to be higher in patients than in controls. Studies of antibodies in humans in oral candidiasis have used both serum and saliva, with the main objectives of identifying responses in relation to clinical disease or sometimes...

Functional Aspects of Serum and Salivary Antibodies to Candida

There have been many attempts to identify functional activity of serum or salivary antibodies in vitro and in addition some conclusions can be drawn from in vivo models. (Table 3.4) Thus Holmes et al. (2002) showed that while whole saliva promoted the binding of C. albicans to epithelial cell lines, human Candida-specific IgA antibodies could inhibit the adhesion. These antibodies could be absorbed by both Candida or by an anti-IgA. These findings seem to suggest that IgA in the human oral...

General Considerations for Oral Mucosal Immunity to Candida

Theoretically, SIgA, serum IgG transu-dating through the mucosa, and cellular immunity might all play a role in protection of mucosal surfaces against Candida infections. Animal models have largely concentrated on systemic candidiasis possibly because of the difficulties in obtaining reproducible and relevant models of mucosal candidiasis. Evidence suggests a role for CMI, even at mucosal surfaces. Infection with C. albicans is an almost universal finding in patients with severe...

Host Factors Predisposing to Oral Candidiasis

Oral candidiasis is a superficial mycosis and can present in a variety of clinical forms. The presence of Candida alone is not an indication of disease since yeasts can be found as a commensal in approximately 40 of the population. Candidiasis is essentially a disease of the diseased and reflects as much changes in host defences as increased pathogenicity of the organism. Oral can-didiasis has been associated with a variety of predisposing factors and these are summarised in Table 3.1.

Clinical Features of Oral Candidiasis

All Candida species form the same type of oral lesions clinically (Redding, 2001). However, recent evidence suggests that mixed infections with more than one species may be associated with more severe symptoms and are more difficult to treat (Redding et al., 2002). There are three main clinical variants of oral candidiasis the pseudomembranous (also known as thrush), the hyperplastic, and the erythematous (Axell et al., 1997). The hyperplastic form is accompanied by extensive epithelial...

Epithelial Cell Factors TLR etc

This aspect is covered in more detail elsewhere. However, one of the exciting new areas of immunology has been the recognition that epithelial cells play an active part in innate immunity and that epithelial cells can produce factors interactive with the immune system upon contact with bacteria and other antigens. Some of these factors appear to be microbicidal to Candida. For example, Pivarcsi et al. (2003) showed that antimicrobials induced from epithelial cells can kill Candida. This...

Peroxidase and Myeloperoxidase

Peroxidase originates from two main sources in the oral cavity. Salivary peroxidase is synthesized by acinar cells in major salivary glands and myeloperoxidase (MPO) is derived from the neutrophil primary granules. Monocytes also contain MPO in their primary granules, whereas macrophages are known to lack this enzyme (Marodi et al., 1991). These enzymes combine with H2O2 and thiocyanate or iodide ions to produce hypothiocyanate, or hypoiodite, which are powerful oxidizing agents. In the...

Defensins

Defensins are cationic, arginine-rich peptides containing 28 to 44 amino acids. Their molecular weights vary from 3 to 5 kDa. They all share a typical tertiary structure despite differences in primary structure. Defensins have a broad antimicrobial spectrum encompassing not only Candida but also Gram-negative and Gram-positive bacteria. They are also chemotactic for mono-cytes, PMNs, and T cells. The highest density is found in granulocytes where defensins 1-4 may make up 10 of the total...

Stephen J Challacombe Durdana Rahman Mukesh Mistry and Julian R Naglik

Classification of Oral Candida 4. General Considerations of Oral Mucosal Immunity to 5. Humoral Immunity against Oral 5.1. Saps and Oral Humoral 5.2. Host Immune Responses to 5.3. Functional Aspects of Serum and Salivary Antibodies to Candida 46 5.4. Oral Immunity to Candida in HIV 5.5. Serum Antibodies Responses to Oral Candida Infection in Humans 47 5.6. Salivary IgA Subclass Antibodies to 6. Innate Factors against Oral Candidiasis 6.1. Epithelial Cell...

Invasive Fungal Sinusitis

Within invasive fungal sinusitis there are two distinct subtypes, acute and chronic. Acute sinusitis occurs in immunocompro-mised hosts (bone marrow transplant patients, HIV, etc.) and generally lasts for less than 4 weeks. In the literature it is commonly referred to as fulminant sinusitis, conveying the rapid disease progression and destruction affiliated with the infection (Ferguson, 2000a). Characteristically the disease progresses in a matter of days, with hyphal growth and extension...

Structure of the Oral Mucosa

The oral mucosa is a highly permeable tissue, with regional variations, as the type and keratinization status of the epithelial cell layer varies in different locations of the oral cavity. The oral cavity is lined by at least four different types of mucosa (Squier and Finkelstein, 2003). While nonkeratinized epithelium lines the majority of the oral cavity, covering the hard palate and gingiva is the masticatory mucosa, which receives the most severe mechanical forces and has stratified...

Classification of Oral Candida Infections

Candida species can be found as commensals in the mouths approximately 40 of normal subjects in amounts up to approximately 800 colony forming units (CFU) ml. There is usually some underlying precipitating factor for oral candidiasis, often an immunodeficiency and in patients with various forms of candidiasis (Table 3.2), salivary counts of greater than 20,000 CFU ml may be found. Oral candidiasis is a common condition, especially in patients with xerostomia, those taking immunosup-pressive...