Insect Immune System and Parallels with the Innate Immune Response of Mammals

Melanisation Insect

Insects have maintained a parallel immune response to the innate immune response of vertebrates, despite their divergence approximately 500 million years ago. The preservation of this immune response highlights its success and efficacy in combating microbial infection (Kavanagh & Reeves, 2004 Salzet, 2001 Leclerc & Reichhart, 2004 Kanost et al., 2004). It was initially thought that the innate immune response was inferior to the adaptive immune response, as the adaptive immune system has...

Tuning the Adaptive Immune Responses The Instructive Role of DC

As DC are equipped with several TLR, they are the main connectors of the innate and adaptive immune systems. DC are bone marrow-derived cells of both lym-phoid and myeloid stem cell origins that populate all lymphoid organs, as well as nearly all nonlymphoid tissues and organs. The dual activation tolerization function of DC is mediated by their capacity to change the context of antigen presentation and to communicate to T cells the nature of the antigens they are presenting. This process...

Offensive Virulence Factors

Offensive virulence factors are molecules that enable the fungus to interact directly with the host, causing it damage. They include secreted enzymes such as proteases, peptidases and phospholipases, secreted toxins, and adhesins. Proteases (also known as peptidases) play a major role in the virulence of several fungal pathogens by digesting host proteins and thereby enhancing tissue penetration (Monod et al., 2002). During the previous decade, considerable efforts were made to identify A....

Haemocytes and their Role in the Immune Response

Haemocytes are the immune cells of the insect and are found attached to internal organs of the insect, such as the fat body, trachea, or the digestive system, and circulating freely within the haemolymph. The density of haemocytes circulating in the haemolymph is indicative of infection, with low haemocyte densities being associated with infection and high haemocyte densities associated with healthy insects. This has been explicitly demonstrated by Bergin et al. (2003), where infection of G....

The Adaptive Immunity Th1 Th2 and Th17 Cells

Serological and skin reactivity surveys indicate that fungal infections are common, but clinical disease is rare, consistent with the development of acquired immunity. Underlying acquired immunity to C. albicans, such as the expression of a positive delayed type hypersensitivity, is demonstrable in adult immunocompetent individuals, and is presumed to prevent mucosal colonization from progression to symptomatic infection (Puccetti et al., 1995). Lymphocytes from healthy subjects show strong...

C albicans and the Host Immune System

When C. albicans infects a host it enters into a battle with the host immune system, particularly cells of the innate immune system. Neutrophils and macrophages are involved in mopping up fungal cells found in the bloodstream, and it is important to know how both host and fungus respond during these interactions. The adaptive immune response is involved in determining the outcome of systemic infection, so interactions of C. albicans with the major antigen processing and presenting cells,...

Modulation of the Immune Response in Dermatophytosis

While immunological mechanisms provide potential methods of defense, the persistence of infection in many apparently healthy individuals suggests that these are either ineffective or inoperative in some patients. It has been shown that some patients with persistent dermatophytosis have defective lymphocyte blastogenesis to T-cell mitogens and dermatophyte antigen and that this can be reversed either by substituting heterologous (foetal calf) for autologous serum or after successful antifungal...

Defensive Virulence Factors

Defensive virulence factors are traits that enable the fungus to proliferate in the hostile environment of the human body. They include the ability to grow at human body temperature (thermotolerance), the protective capacity of the fungal cell wall and its components (polysaccharides, proteins, pigments) and the ability to degrade reactive oxygen species produced by the host immune system. A. fumigatus thermotolerance is a trait critical for survival in decomposing organic matter. However,...

Superficial Mucosal Infections

Superficial mucosal lesions occur in the oral and vaginal cavities and are commonly called 'thrush'. These infections can occur in both immunocompetent and immuno-compromised persons. Oral thrush, or oral candidiasis, is a common problem seen in infants, the elderly, and in cancer patients, particularly those with haematological malignancies, receiving chemotherapy, or receiving head and neck radiotherapy. It is characterised by white growth on mucous membranes of the oral cavity, which have...

Vaginal Epithelium Model

The reconstituted human vaginal epithelium (RHVE) resembles the multilayer human vaginal mucosa and is commercialized by Skinethic Laboratory (Nice, France). It is based on a cell line which was obtained by culturing transformed human keratinocytes of the cell line A431 derived from a vulval epidermoid carcinoma (Rosdy et al., 1986). The RHVE model was valid for evaluating the phenotype of mutants in the agglutinin-like sequence (ALS) family in C. albicans. The expression of ALSs proteins in...

Category Ed50 Munoz Et Al

Figure 4.4 Chemical structures of Sordarin and its derivatives, azosordarin and R-135853 decreasing toxicity and increasing target specificity (Abuhammour and Habte-Gaber, 2004 Ng et al., 2003). Incorporating AMB into phospholipid vesicles (Liposomes) or cholesterol esters permit delivery of larger amounts of the drug with minimal nephrotoxicity. AMB lipid complex (AMBLC) was the first lipid-formulated AMB product to be approved by the FDA for clinical. The lipid-formulated AMB colloidal...

Novel Therapies Antifungal Monoclonal Antibodies

Gordon and Lapa (1964) established that the administration of serum Abs enhances the outcome of antifungal chemotherapy in cryptococcosis. Several fungal infections are marked by significant Ab responses, however, the extent to which they confer protection varies depending on Ab isotype (Casadevall, 1995) and the MHC background of the host (Rivera & Casadevall, 2005). Variations in Ab VH gene usage were reported to significantly influence the specificity and efficacy of Abs, hence the...

Echinocandins

Echinocandins are fatty acid derivatives of cyclic hexapeptides and consist of a diverse family of lipopeptides including caspofungin, micafungin, and anidulafungin. Echinocandins are noncompetitive inhibitors of the (1,3)-P-d-glucan synthase (Morrison, 2006 Turner et al., 2006 Randhawa & Sharma, 2004). Fungistatic effects result from blockage of cell wall synthesis that reduces cell growth and fungicidal effects result from loss of cell wall integrity, loss of mechanical strength and...

C albicans Cell Surface

The proteins displayed on the cell wall are obviously important as it is these cells that can be sensed and interact with host cells (Sohn et al., 2006a). Glycosylphosp hatidylinositol (GPI)-anchored proteins in the cell wall have also been investigated using proteomic approaches. Theoretically, C. albicans strain SC5314 could display 104 GPI-anchored proteins on its cell surface (De Groot et al., 2003). However, proteomic analysis of exponentially growing yeast cells demonstrated that only 14...

Candidaemia

Candidaemia, i.e. bloodstream infection by Candida species, is a significant clinical problem, with the attributable mortality estimated to be between 10 and 71 Kibbler et al., 2003 Safdar et al., 2004 Zaoutis et al., 2005 Falagas et al., 2006 Vigouroux et al., 2006 Zaragoza amp Peman, 2006 . In recent years there was a gradual increase in the incidence of Candidaemia Bassetti et al., 2006 Sandven et al., 2006 Sendid et al., 2006 . The symptoms of Candidaemia generally resemble those found for...

Dampening Inflammation and Allergy to Fungi A Job for Treg Cells

The inflammatory response to fungi may serve to limit infection but may also contribute to pathogenicity, as documented by the occurrence of severe fungal infections in patients with immunoreconstitution disease Cheng et al., 2000 . These patients may experience intractable fungal infections despite recovery from neutropenia and the occurrence of adaptive immune responses. The above considerations imply that immunoregulation may be essential in fine-tuning inflammation and adaptive Th...