Candidiasis
Rebecca A. Cox in Immunology of the Fungal Diseases, 2020
Many of the subcellular components of C. albicans investigated have been polysaccharides containing varying proportions of glucose and mannose, presumably in the form of glucan and mannan, in addition to small amounts of protein. Several groups,311,321,326,327 however, have turned their attention to mannan, a polymer essentially devoid of glucose, and its potential for immunomodulation. Aside from the potential interaction of mannan with phagocytic cells,326,327 mannan, as extracted by traditional techniques, appears to be heterogeneous and has within the mixture components which may be suppressive or enhancing of non-Candida antibody responses.321 Interestingly, the unfractionated mannan functions well as an antigen to detect DTH in mice immunized with viable C. albicans, and like cell-wall glycoprotein described above,320 it will suppress the development of that hypersensitivity if administered intravenously prior to sensitization.330 The components responsible for suppression or enhancement of the antibody responses to non-Candida immunogens, i.e., sheep erythrocytes and Type III pneumococcal polysaccharide, could be separated on the basis of size or charge using column chromatography.321 The mechanisms involved in the regulatory phenomena have not been elucidated.
Candida
Dongyou Liu in Laboratory Models for Foodborne Infections, 2017
Thus, serological tests can be performed by detecting antigens and antibodies. Such tests are used in combination with conventional techniques for improving the diagnosis. The mannan and (1,3)-β-d-glucan detection is widely used. The mannan constituent of the Candida cell wall is a polysaccharide used as a target of many serological tests performed in serum or plasma specimens since it induces a strong antibody response.40 Tests based on the detection of antibodies directed against the mannan antigen are recommended in combination with those based on Candida antigens for improving the sensitivity and the specificity of the diagnosis.41 The commercial Platelia Candida antigen and antibody tests (Bio-Rad Laboratories) are the most commonly used serological methods for detecting Candida based on mannan.41,42 However, since the antibodies could be not produced in immunocompromised patients, it is very complicated to diagnose Candida infections in them.34,41 (1,3)-β-d-Glucan is also a cell wall component not only of Candida species but also of most of the other fungi. Several assays have been developed for quantifying such compounds in blood as a tool in the diagnosis of many pathogenic fungi including Candida.40,43
Serodiagnosis: Antibody and Antigen Detection
Johan A. Maertens, Kieren A. Marr in Diagnosis of Fungal Infections, 2007
Several LA tests for mannan detection have been commercialized. The first of these, the LA-Candida Antigen Detection System (Immuno-Mycologics, Inc., Norman, Oklahoma) utilized polyclonal antimannan antibodies to detect the antigen in serum pretreated with heat and protease. However, several evaluations by different groups indicated that this test was too insensitive to be helpful in the early diagnosis of candidiasis (138,139). A second commercial LA test (Pastorex Candida, Bio-Rad Laboratories), introduced in 1991 (140), has also been found to be highly specific but poorly sensitive. The monoclonal antibody, EB-CA1, used in this test is directed against an epitope derived from C. albicans mannan, but it also reacts with several other species including Candida glabrata, Candida parapsilosis, and Candida tropicalis (141). In an initial retrospective evaluation, the test was noted to have a sensitivity of 53% and a specificity of 100% for the diagnosis of invasive candidiasis in immunocompetent patients (142). Although samples were pretreated by boiling in the presence of EDTA to dissociate immune complexes, the test showed low sensitivity in patients who had high titers of antimannan antibodies. Other groups, however, have reported the Pastorex Candida Antigen test to have sensitivities ranging from 0% to only 28% (97,143,144).
Carbohydrate-containing nanoparticles as vaccine adjuvants
Published in Expert Review of Vaccines, 2021
Xinyuan Zhang, Zhigang Zhang, Ningshao Xia, Qinjian Zhao
The natural polysaccharide mannan possesses immunomodulatory properties [54,55]. NPs containing mannan are able to enhance the immune response, as vaccine adjuvants, especially in vaccines against human immunodeficiency virus (HIV). Mannan is extensively distributed in plants and the microbial cell wall, consisting of β-1,4 glycosidic bonds linked to D-mannose [5]. Mannan could promote the maturation of DCs dependent on TLR4 and activate the inflammasome to modulate immune response [16]. Mannan could also interact with mannan-binding lectin and C-type lectin receptors that are widely expressed on immune cells (including all myeloid cells and lymphocytes) [16,56,57]. Mannan-binding signals activate pathways to induce the production of cytokines and chemokines, promoting Th cell differentiation [58]. In consideration of the capacity of mannan to interact with pattern recognition receptors and mediate the immune response, mannan-containing NPs have been assessed in vaccines as adjuvants to achieve antigen target delivery and boost the immune response.
Amphoteric Mannan as an Immune Response Modifier. New Model Immunobiologically Active Candida albicans Mannan-Based Formula
Published in Immunological Investigations, 2023
Ema Paulovičová, Lucia Paulovičová, Alžbeta Čížová, Jana Mečárová, Romana Vrzoňová, Pavol Farkaš, Slavomír Bystrický
The yeast strain Candida albicans CCY 29-3-100 (serotype A) 207/II-8 Hasenclever deposited in 1963 in the CCY Culture Collection of Yeasts, Institute of Chemistry, Center for Glycomics, Slovak Academy of Sciences, Bratislava, Slovakia, was used to isolate and purify cellular mannan from fresh biomass. Mannan was isolated as a mannan–copper complex (Jones and Stoodley 1965) from the yeast cell wall of C. albicans, serotype A. Mannan (M; 10–1000 kDa, PDI ≈ 3.3) was ultrasonically degraded (MUS; ≈ 35 kDa, PDI = 1.6) by a method described elsewhere (Čížová et al. 2015). The detailed procedure of isolation, degradation, and the characterization of mannan is given in the Supplementary data. The prepared mannan was free of proteins or chitoligomers since no nitrogen was detected by elemental analysis (Table S2, Supplementary data). The glucose content in the isolated mannan was less than 1.7 mass % as confirmed by monosaccharide composition analysis (Table S2, Supplementary data). Contamination with lipids was further excluded by FTIR and NMR spectroscopies confirming the structure and purity of the isolated mannans (Fig. S1 and S2, Supplementary data).
Combined vaccines for prophylaxis of infectious conditions
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2019
Pravin Shende, Mansi Waghchaure
The vaccine is composed of a carbohydrate polymer comprising mannose and influenza virus (flu) antigens in admixture. The flu antigens are obtained from either human or animal influenza virus-like avian flu or equine flu. The flu antigen is generally taken from the whole inactivated influenza virus. Mannose is a carbohydrate polymer, consists of mannan and more preferably oxidized mannan. Mannan is a polysaccharide which enhances the formation of some antibodies like IgG1, IgG2a and IgA in serum and IgA in mucosal sites and in the lung. Oxidized mannan is a non-toxic and an effective adjuvant combined with antigens for vaccination against infections which occur via mucosal membrane [26]. In the survey regarding the adjuvant effect of mannan in the vaccine, it is mentioned that no significant immunization was produced by mannan when used in a small quantity. Hence the study was carried out using varying levels of mannan concentration [27]. The intra-nasal administration of admixture showed that inactivated H1N1 mixed with mannan induced higher serum IgG and respiratory-tract IgA than H1N1 alone. The action is mannan dose-dependent and IgG1 and IgG2 were induced by the vaccination and it induces humoral and cellular immunity.
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