Candida Cell Wall Research Articles

A Blockwise Approach to the Synthesis of (1→2)‐Linked Oligosac­char­ides Corresponding to Fragments of the Acid‐Stable β‐Mannan from the Candida albicans Cell Wall

AbstractOligomannosides comprising short β‐(1→2)‐oligomannosyl blocks attached through a glycoside bond to an α‐(1→2)‐linked oligomannoside are a constituent of side chains of the mannan from the Candida cell wall. This type of oligomannoside is known as an acid‐stable β‐mannan and corresponds to the antigenic factor 6. In this communication, we report a convergent blockwise synthesis of four spacer‐armed oligomannosides of this type including from 1 to 4 β‐mannosyl and 2–3 α‐mannosyl residues. β‐(1→2)‐Oligomannosyl thioglycosides and sulfoxides containing up to four mannose units were employed for introduction of β‐oligomannoside sequences. The efficiency of β‐mannosylation with mono‐ and oligomannoside donors was shown to depend more on the structure of the reaction partners than on the applied activation protocol. The oligomannosides obtained will be used to prepare various molecular tools for investigation of the Candida cell wall.

Differential effects of antifungal agents on expression of genes related to formation of Candida albicans biofilms.

The purpose of this study was to analyse specific molecular mechanisms involved in the intrinsic resistance of C. albicans biofilms to antifungals. We investigated the transcriptional profile of three genes (BGL2, SUN41, ECE1) involved in Candida cell wall formation in response to voriconazole or anidulafungin after the production of intermediate and mature biofilms. C. albicans M61, a well-documented biofilm producer strain, was used for the development of intermediate (12 h and 18 h) and completely mature biofilms (48 h). After exposure of cells from each biofilm growth mode to voriconazole (128 and 512 mg l(-1)) or anidulafungin (0.25 and 1 mg l(-1)) for 12-24 h, total RNA samples extracted from biofilm cells were analysed by RT-PCR. The voriconazole and anidulafungin biofilm MIC was 512 and 0.5 mg l(-1) respectively. Anidulafungin caused significant up-regulation of SUN41 (3.7-9.3-fold) and BGL2 (2.2-2.8 fold) in intermediately mature biofilms; whereas, voriconazole increased gene expression in completely mature biofilms (SUN41 2.3-fold, BGL2 2.1-fold). Gene expression was primarily down-regulated by voriconazole in intermediately, but not completely mature biofilms. Both antifungals caused down-regulation of ECE1 in intermediately mature biofilms.

Serological response and diagnostic value of recombinant candida cell wall protein enolase, phosphoglycerate kinase, and β-glucosidase.

There are no specific signs and symtoms for invasive candidiasis (IC), which makes its diagnosis a challenge. Efforts have been made for decades to establish serological assays for rapid diagnosis of IC, but none of them have found widespread clinical use. Using a systemic candiasis murine model, serological response to recombinant proteins of enolase (rEno1), phosphoglycerate kinase (rPgk1), and β-glucosidase (rBgl2) were evaluated and rEno1 was found to possess the strongest immunoreactivity, followed by rPgk1 and rBgl2. Likewise, IgG antibody titers to rEno1, rPgk1, and rBgl2 in the positive sera of proven IC patients were determined by ELISA. Results show anti-rEno1 antibody possesses the highest titer, followed by rPgk1 and rBgl2. Antibodies against rEno1, rPgk1, and rBgl2 were detected by ELISA tests in a group of 52 proven IC patients or 50 healthy subjects, The sensitivity, specificity, positive and negative predictive values were 88.5, 90.0, 90.2, and 88.2% for anti-rEno1 detection, 86.5, 92.0, 91.8, and 86.8% for anti-rPgk1 detection, and 80.8, 90.0, 89.4, and 81.8% for anti-rBgl2 detection, respectively. The data clearly demonstrate that the recombinant proteins of Eno1, Pgk1, and Bgl2 are promising candidates for IC serodiagnosis. There's great possibility that the recombinant Eno1 will be more applicable in serodiagnosis and vaccine research on account of its strong serological response.

Systems Level Dissection of Candida Recognition by Dectins: A Matter of Fungal Morphology and Site of Infection.

Candida albicans is an ubiquitous fungal commensal of human skin and mucosal surfaces, and at the same time a major life-threatening human fungal pathogen in immunocompromised individuals. Host defense mechanisms rely on the capacity of professional phagocytes to recognize Candida cell wall antigens. During the past decade, the host immune response to Candida was dissected in depth, highlighting the essential role of C-type lectin receptors, especially regarding the power of the Dectins’ family in discriminating between the tolerated yeast-like form of Candida and its invading counterpart, the hyphae. This review focuses on the immuno-modulatory properties of the Candida morphologies and their specific interactions with the host innate immune system in different body surfaces.

AFM force spectroscopy reveals how subtle structural differences affect the interaction strength between Candida albicans and DC-SIGN.

The fungus Candida albicans is the most common cause of mycotic infections in immunocompromised hosts. Little is known about the initial interactions between Candida and immune cell receptors, such as the C-type lectin dendritic cell-specific intracellular cell adhesion molecule-3 (ICAM-3)-grabbing non-integrin (DC-SIGN), because a detailed characterization at the structural level is lacking. DC-SIGN recognizes specific Candida-associated molecular patterns, that is, mannan structures present in the cell wall of Candida. The molecular recognition mechanism is however poorly understood. We postulated that small differences in mannan-branching may result in considerable differences in the binding affinity. Here, we exploit atomic force microscope-based dynamic force spectroscopy with single Candida cells to gain better insight in the carbohydrate recognition capacity of DC-SIGN. We demonstrate that slight differences in the N-mannan structure of Candida, that is, the absence or presence of a phosphomannan side chain, results in differences in the recognition by DC-SIGN as follows: (i) it contributes to the compliance of the outer cell wall of Candida, and (ii) its presence results in a higher binding energy of 1.6 kB T. The single-bond affinity of tetrameric DC-SIGN for wild-type C. albicans is ~10.7 kB T and a dissociation constant kD of 23 μM, which is relatively strong compared with other carbohydrate-protein interactions described in the literature. In conclusion, this study shows that DC-SIGN specifically recognizes mannan patterns on C. albicans with high affinity. Knowledge on the binding pocket of DC-SIGN and its pathogenic ligands will lead to a better understanding of how fungal-associated carbohydrate structures are recognized by receptors of the immune system and can ultimately contribute to the development of new anti-fungal drugs.

Demonstration of β-1,2 mannan structures expressed on the cell wall of Candida albicans yeast form but not on the hyphal form by using monoclonal antibodies

Candida albicans is a polymorphic fungus that may be observed as both commensal and opportunistic pathogen in humans. As one of the major components of Candida cell wall structure, mannan plays an important role in the fungus-host cell interaction and in virulence. The ability to switch from yeast to hypha form of microorganism is crutial in the development of C.albicans infections. Hyphal form has different antigenic properties compared to yeast form and structural changes occur in the yeast cell wall during transition from yeast to hypha form. Although there are several factors associated with this transition process, sufficient information is not available. The aim of this study was to investigate the change of configuration in mannan structure found in C.albicans cell wall by using monoclonal antibodies. C.albicans (NIHA 207) serotype A strains were used as test strains throughout the study, together with Salmonella choleraesuis 211 and Salmonella infantis as controls with similar cell wall structures to that of C.albicans. Cultures were maintained on YPD-agar medium by incubating at 28°C for yeast forms, and on YPD-broth medium in a shaking incubator at 37°C for 3-4 hours for the growth of hyphal forms. Cells were harvested in the exponential phase, and after being washed, the mannan content from C.albicans were extracted from pellet by heating in 20 mM sodium citrate buffer for 90 minutes at 125°C. Hybridoma technique was used for the production of monoclonal antibodies. After immunizing the Balb/C mice with antigen, the splenocytes were harvested and fusion was performed between spleen cells and F0 myeloma cells. The clones grown in HAT medium were screened for the presence of antibody producing hybrid cells by ELISA method. The antibody isotypes were determined by using a commercial kit (Pierce Biotechnology, ABD). The culture supernatants which contained monoclonal antibodies were collected and purified according to the ammonium sulphate method. Sandwich ELISA and immunofluorescence (IF) methods have been used to detect the experimental reactions. In our study, highly specific class IgM murine monoclonal antibodies (mAb-2B7) against C.albicans yeast cell wall were obtained from clone 2B7. These antibodies cross-reacted with S.choleraesuis 211 and S.infantis bacteria sharing similar cell wall structure of C.albicans. The existence of mannan β-1,2 bonds on the surface of C.albicans yeast form was confirmed with a commercial monoclonal antibody (mAb-ACMK-1; Matriks Biotek(®), Turkey) specific for those bonds. Besides, mAb-ACMK-1 interacted with C.albicans yeast form and gave intense fluorescence (high positive reaction) in IF method, but no fluorescence (negative) was detected with hyphal form. This data, obtained for the first time with this study, indicates that the mannan β-1,2 bonds are either found infrequently or none in the fungal hyphal wall. Although both monoclonal antibodies recognize the mannan antigen, mAb-2B7 reacted with S.choleraesuis 211, while mAb-ACMK-1 did not, due to the difference of epitope specificity. In conclusion, monoclonal antibodies may facilitate the characterization of antigenic structures of Candida, which will lead for the identification of new determinants that may increase the sensitivity and specificity of commercial tests used for mannan detection in serum.

Immunological basis of anti-Candida vaccines focused on synthetically prepared cell wall mannan-derived manno-oligomers.

The increasing incidence of diseases caused by Candida species and complications in individuals with impaired immunity require new strategies for candidiasis treatment and prevention. The available therapies are often of limited effectiveness in immunocompromised patients, resulting in treatment failures, chronic infections and high mortality rates. Research directed at identifying the composition of an effective vaccine is required. Mannan forms the outermost layer of the Candida cell wall and has an essential role in modulation of anti-Candida host immune responses. Therefore, Candida cell wall mannan and synthetically prepared manno-oligomer-based glycoconjugates are the foci of attention in vaccine candidate development. Almost all of the existing human vaccines mediate protection through neutralizing antibodies. Th1-based and/or Th17-based cellular immune responses, rather than antibody-mediated immunity, mediate protection against candidiasis. Findings of published studies indicate that analysis of cellular immune responses as well as antibody responses is necessary when assessing the immunomodulatory properties of manno-oligomer-based glycoconjugates that are potential anti-Candida vaccine candidates.

Diagnostic potential of antibody titres against Candida cell wall β-glucan in Kawasaki disease

Kawasaki disease (KD) is an acute vasculitis syndrome of unknown aetiology in children. The administration of Candida cell wall antigens induced KD-like coronary vasculitis in mice. However, the responses of KD patients to Candida cell wall antigen are unknown. In this study, we examined the response of KD patients to β-glucan (BG), one of the major fungal cell wall antigens, by measuring the anti-BG titre. In KD patients, the anti-C. albicans cell wall BG titre was higher than that in normal children. The anti-BG titre was also higher in KD patients compared to children who served as control subjects. The efficacy of intravenous immunoglobulin (IVIG) therapy in KD is well established. We categorized the KD patients into three groups according to the therapeutic efficacy of intravenous immunoglobulin (IVIG) and compared the anti-BG titre among these groups. Anti-BG titres were similar in the control group and the non-responsive group. In the fully responsive group, the anti-BG titre showed higher values than those in the normal children. This study demonstrated clinically that KD patients have high antibody titres to Candida cell wall BG, and suggested the involvement of Candida cell wall BG in the pathogenesis of KD. The relationship between IVIG therapy and anti-BG titre was also shown. These results provide valuable insights into the therapy and diagnosis of KD.

Presence of Candida cell wall derived polysaccharides in the sera of intensive care unit patients: relation with candidaemia and Candida colonisation

IntroductionPrompt diagnosis of candidaemia and invasive candidosis is crucial to the early initiation of antifungal therapy. The poor sensitivity of blood cultures (BCs) has led to the development of fungal glycan tests as a diagnostic adjunct. We analysed the performance of tests for the detection of circulating β-D-1,3-glucan (BDG) and mannan in the intensive care unit (ICU) setting.MethodsThis retrospective, case–control study included 43 ICU patients with candidaemia and 67 controls, hospitalised on the same ward and assessed weekly for yeast colonisation with simultaneous serum sampling; 340 sera taken before and after positive BCs were available for the cases group and 203 for the controls. BDG and mannan levels were determined using the Fungitell® and Platelia™ Candida Ag tests, respectively.ResultsBDG was detected early in sera from cases patients but was also present in several sera from controls. Increasing the cut-off from 80 pg/mL to 350 pg/mL and 800 pg/mL resulted in sensitivity/specificity ratios of 0.97/0.31, 0.65/0.74, 0.30/0.86, respectively. Detection of mannan was more specific but lacked sensitivity. No obvious correlation was found between BDG and colonisation, but a trend existed between high colonisation and high BDG. Candidaemia relapses were associated with a rise in BDG and mannan but, in contrast to the transient nature of mannan, BDG persisted up to 7 weeks after positive BCs.ConclusionA combination of mannan and BDG tests could be used to guide pre-emptive therapeutic decisions in ICU patients.

Immune cell response to Candida cell wall mannan derived branched α-oligomannoside conjugates in mice

Constructs composed of cell wall mannan-derived moieties conjugated to immunogenic proteins could be promising agents for induction of protective anti-Candida immune responses. This report is focused on the cellular immune response differences induced by BSA-based conjugates bearing synthetic α-1,6-branched oligomannosides. For monitoring of the immune responses following active immunization we evaluated changes in the frequencies of T and B lymphocytes and their activation status in the blood and spleen. We compared the immunization-induced changes of co-stimulatory molecules CD80 and CD86 expression on blood neutrophils and Th1/Th2 polarization of the immune response based on IFN-γ, TNF-α (pro-Th1), IL-4, and IL-10 (pro-Th2) cytokines levels and induction of IL-17. The results pointed out a comparable effect of the conjugates on the modulation of T and B lymphocytes frequencies in blood and spleen. Both conjugates induced upregulation of CD25 surface antigen on CD4(+) T lymphocytes, independently on the structural differences of oligosaccharides. The differences in structure of oligomannoside antigens or conjugate constructs were reflected in the increase of co-stimulatory molecules CD80 and CD86 expression on neutrophils, and in induced cytokine response. M5-BSA conjugate induced only a slight increase in CD80 expression but a significant increase in IFN-γ, TNF-α, and IL-10. M6-BSA conjugate induced a significant increase of CD80 expression and increase of TNF-α, IL-4, and IL-10. Obtained data demonstrate the importance of cellular immune response analysis for investigation of immunomodulatory properties of oligomannoside-protein conjugates.

Synthetically prepared glycooligosaccharides mimickingCandida albicanscell wall glycan antigens - novel tools to study host-pathogen interactions

The immunobiological efficacy of synthetically prepared mannooligosaccharides and a glucooligosaccharide mimicking the structure of Candida albicans cell wall glycans was assessed in vivo and in vitro to exploit immune responses. The exposure of mice splenocytes to BSA-based conjugates of synthetic oligomannosides and oligoglucoside revealed intense influence on T-cell subset polarization. The conjugates biased the immune responses towards Th1 and Th17 with respect to the prevalence of interferon-gamma (IFN-γ) and interleukin (IL)-17 (IL-17) over IL-4 and IL-10 levels. The inflammatory activity of the conjugates has been evaluated based on the induction of pro-inflammatory cytokines. Postvaccination, antimannooligosaccharide and antiglucooligosaccharide antisera were subjected to an evaluation of the structure-immunomodulation activity relationship. Clinical isolates of C.albicans CCY 29-3-32 and C.albicans CCY 29-3-164 were applied to study interactions between Candida cells and anti-oligosaccharide antibodies. In situ recognition of parietal oligomannosyl and oligoglucosyl sequences in C.albicans cell wall by the antisera raised against BSA-based conjugates of synthetic oligomannosides and oligoglucoside revealed the effective recognition of specific distribution of natural oligosaccharide sequences in the cell wall of C.albicans serotype A. With respect to these results, it can be concluded that new, synthetically prepared oligosaccharides mimicking Candida cell wall structures represent prospective immunobiologically effective components for further immunopharmacologically relevant Candida vaccine design.

Effect of Branched α‐Oligomannoside Structures on Induction of Anti‐Candida Humoral Immune Response

Several studies have established the potential efficacy of humoral immunity, primarily mannan-specific antibodies, in host protection against major fungal pathogen Candida albicans. In this study, we analysed humoral immune response induced by immunization with BSA-based conjugates bearing synthetic α-1,6-branched oligomannosides (pentamannosides (M5) or hexamannosides (M6)) mimicking antigenic sequences of Candida cell wall mannan. We analysed the ability of antibodies prepared by immunization to recognize relevant antigenic determinants in mannan polysaccharide structure and in C. albicans yeast and hyphal morphoforms. M6-BSA conjugate induced markedly higher levels of mannan-specific IgG compared with M5-BSA conjugate. In contrast to M5-BSA conjugate, M6-BSA conjugate induced immunoglobulin isotype class switch from IgM to IgG, as revealed also from ELISPOT analysis. Immunization-induced antibodies showed higher reactivity with hyphal form of C. albicans cells. The reduced immunogenicity of M5-BSA conjugate seems to be related to branching point location at terminal non-reducing end in comparison with M6-BSA oligomannoside with branching point at non-terminal location. Candidacidal activity assay revealed different capacity of sera prepared by immunization with M5-BSA and M6-BSA conjugates to improve candidacidal activity of polymorphonuclear leucocytes. Limited capacity of α-1,6-branched oligomannoside--BSA conjugates to induce antibodies significantly enhancing candidacidal activity of polymorphonuclear leucocytes--was presumably related to absence of antibodies with strong reactivity to corresponding antigenic determinants in natural cell wall mannan and with reduced ability to activate complement. The study documented markedly structure-dependent immunogenicity and limited capacity of branched α-mannooligosides conjugates to induce production of potentially protective antibodies.

Identification of Candida albicans heat shock proteins and Candida glabrata and Candida krusei enolases involved in the response to oxidative stress

AbstractIn the past two decades, Candida species have become the second leading cause of invasive mycosis in immunocompromised patients. In order to colonize their hosts, these microorganisms express adhesins and cell wall proteins that allow them to adhere and neutralize the reactive oxygen species produced by phagocytic cells during the respiratory burst. However, the precise mechanism by which Candida cell wall proteins change their expression in response to oxidative stress has not been described. In an attempt to understand this change in response to oxidative stress, in this study, three Candida species, namely, C. albicans, C. glabrata and C. krusei, were exposed to increasing concentrations of H2O2 and induced cell wall proteins were identified by two-dimensional gel electrophoresis and peptide mass fingerprinting. Sequence analysis of differential proteins led to the identification of two heat-shock proteins in C. albicans, two enolases in C. glabrata and one enolase in C. krusei. Enolases may be involved in the protection of pathogenic cells against oxidative stress as suggested by the decrease in their expression when they were exposed to high concentrations of H2O2. To our knowledge, this is the first demonstration that expression of these proteins changes in response to oxidative stress in different Candida species. This knowledge can eventually facilitate both an early diagnosis and a more efficient treatment of this mycosis.

Composition of Cassia fistula Oil and its Antifungal Activity by Disrupting Ergosterol Biosynthesis

Cassia fistula oil was investigated for antifungal activities against standard and clinical isolates of Candida species. Gas chromatography coupled with mass spectrometric (GC-MS) analysis of C. fistula oil revealed the presence of antimicrobial compounds like beta-sitosterol, stigmasterol, ergosterol, betulinic acid, lupeol, fucosterol, alpha-amyrin and friedelin. The minimum inhibitory concentration (MIC) of the pulp and seed oils ranged between 250-300 and 350-500 microg/mL respectively. Both oils also inhibited by > or = 63.8% ergosterol bio-synthesis in Candida cell wall {fluconazole (standard) > or = 89.1%)}. The MICs were significantly correlated with the ergosterol content decrease in the cell wall (Student's t test p < or = 0.005). We can, therefore, conclude that active compounds are present in Cassia fistula oil that primarily target ergosterol biosynthesis in Candida cell wall.

Humoral and cell-mediated immunity following vaccination with synthetic Candida cell wall mannan derived heptamannoside–protein conjugate: Immunomodulatory properties of heptamannoside–BSA conjugate

Chemically defined glycoprotein conjugate composed of synthetically prepared mannan‐derived heptamannoside with terminal β-1,2-linked mannose residue attached to the α-1,3-linked mannose residues and BSA as carrier protein (M7–BSA conjugate) was analysed for the capacity to induce protective humoral immunity and appropriate alteration cellular immunity. To identify protective antigenic structure of Candida cell wall mannan M7–BSA conjugate was used for BALB/c mice immunization. The obtained results were compared with placebo group and with heat‐inactivated C. albicans whole cells immunization. The administration route of M7–BSA conjugate secondary booster injection significantly affected the intensity of humoral immune response and the specificity of produced antibodies. All prepared sera were able to elevate candidacidal activity of polymorphonuclear leukocytes (PMN) in cooperation with complement. Moreover, polyclonal sera obtained after secondary subcutaneous (s.c.) booster injection of M7–BSA conjugate were able to induce candidacidal activity of PMN also in complement independent manner. M7–BSA conjugate immunization induced increases of phagocytic activity and respiratory burst of granulocytes, caused a raise of the proportion of CD3+ T lymphocytes and increased the CD4+/CD8+ T lymphocyte ratio. We observed also an increasing proportion of CD4+CD25+ T cells compared to immunization with heat inactivated whole C. albicans cells, which in turn promoted an increase of the CD8+CD25+ cell proportion. Immunization with M7–BSA conjugate induced Th1, Th2 and Th17 immune responses as indicated by the elevation of relevant cytokines levels. These data provide some insights on the immunomodulatory properties of oligomannosides and contribute to the development of synthetic oligosaccharide vaccines against fungal diseases.

Insight into the Antiadhesive Effect of Yeast Wall Protein 1 of Candida albicans

Ywp1 is a prominent glycosylphosphatidylinositol (GPI)-anchored glycoprotein of the cell wall of Candida albicans; it is present in the yeast form of this opportunistic fungal pathogen but absent from filamentous forms and chlamydospores. Yeast cells that lack Ywp1 are more adhesive and form thicker biofilms, implying an antiadhesive activity for Ywp1, with a possible role in yeast dispersal. The antiadhesive effect of Ywp1 is transplantable from yeast to hyphae, as hyphae that are forced to express YWP1 lose adhesion in an in vitro assay. Deletion of the GPI anchor results in loss of Ywp1 to the surrounding medium and reduction of the antiadhesive effect, implying an importance of time-dependent residency in the cell wall. Anchor-negative versions of Ywp1 possessing or lacking a C-terminal green fluorescent protein (GFP) tag were created in C. albicans and harvested from culture supernatants; in addition to serving as quantifiable markers for Ywp1 secretion, they revealed that the cleaved 11-kDa propeptide of Ywp1 remains strongly but noncovalently associated with the Ywp1 core. This association is resistant to highly acidic and basic solutions, 8 M urea, and 1% SDS (below 45°C). Above 50°C, SDS dissociates the isolated complex, but even higher temperatures are required to dissociate the propeptide from native Ywp1 that is anchored in a cell wall. This property has permitted detection, for the first time, of orthologs of Ywp1 in other members of the Candida clade. The cleaved propeptide, which carries the sole N-glycan of Ywp1, must participate in the antiadhesive effect of Ywp1.

Prediction of the Clinical Outcome in Invasive Candidiasis Patients Based on Molecular Fingerprints of Five Anti-Candida Antibodies in Serum

Better prognostic predictors for invasive candidiasis (IC) are needed to tailor and individualize therapeutic decision-making and minimize its high morbidity and mortality. We investigated whether molecular profiling of IgG-antibody response to the whole soluble Candida proteome could reveal a prognostic signature that may serve to devise a clinical-outcome prediction model for IC and contribute to known IC prognostic factors. By serological proteome analysis and data-mining procedures, serum 31-IgG antibody-reactivity patterns were examined in 45 IC patients randomly split into training and test sets. Within the training cohort, unsupervised two-way hierarchical clustering and principal-component analyses segregated IC patients into two antibody-reactivity subgroups with distinct prognoses that were unbiased by traditional IC prognostic factors and other patients-related variables. Supervised discriminant analysis with leave-one-out cross-validation identified a five-IgG antibody-reactivity signature as the most simplified and accurate IC clinical-outcome predictor, from which an IC prognosis score (ICPS) was derived. Its robustness was confirmed in the test set. Multivariate logistic-regression and receiver-operating-characteristic curve analyses demonstrated that the ICPS was able to accurately discriminate IC patients at high risk for death from those at low risk and outperformed conventional IC prognostic factors. Further validation of the five-IgG antibody-reactivity signature on a multiplexed immunoassay supported the serological proteome analysis results. The five IgG antibodies incorporated in the ICPS made biologic sense and were associated either with good-prognosis and protective patterns (those to Met6p, Hsp90p, and Pgk1p, putative Candida virulence factors and antiapoptotic mediators) or with poor-prognosis and risk patterns (those to Ssb1p and Gap1p/Tdh3p, potential Candida proapoptotic mediators). We conclude that the ICPS, with additional refinement in future larger prospective cohorts, could be applicable to reliably predict patient clinical-outcome for individualized therapy of IC. Our data further provide insights into molecular mechanisms that may influence clinical outcome in IC and uncover potential targets for vaccine design and immunotherapy against IC.

Chronic mucocutaneous candidiasis and congenital susceptibility to Candida

To give an overview on the clinical spectrum and the molecular background of host defence against Candida. For many decades the molecular causes and the pathogenesis for an increased susceptibility to Candida - and fungal infections in general - have been elusive. In 2009 and 2010 interesting reports on the genetic background and the pathomechanisms involved in chronic mucocutaneous candidiasis (CMC) have been published. The susceptibility to recurrent Candida infections can be a monogenetic Mendelian trait. The sensing of Candida cell wall components and the consecutive intracellular signalling in myeloid cells via CARD9, but also the role of Th17 cells and their cytokines take centre stage in the human host defence against Candida.

Model α-mannoside conjugates: immunogenicity and induction of candidacidal activity

The effect of Candida cell wall mannan-derived alpha-oligomannoside structural components on the modulation of the immune system and their role in protective immunity are studied here. Semi-synthetic alpha-mannoside-bovine serum albumin conjugates were used for immunization of rabbits. Dimeric alpha-mannoside, representing Candida antigenic factor 1, was used as a model of linear alpha-mannoside, and pentameric alpha-mannoside was used as a model of branched oligomannoside side chain structure. The induction of humoral immune response and the functionality of the serum tested by induction of peripheral blood leukocyte (PBL) candidacidal activity are documented. Anti-Candida albicans serotype B immunoglobulins (IgG and IgM) levels were higher than anti-serotype A following immunization with both conjugates. Dimer-conjugate postimmunization sera evidently enhanced C. albicans killing activity of PBLs in candidacidal assay. The study shows the importance of alpha-mannoside structures in perspective anti-Candida vaccine with a broad spectrum of effectiveness.

Binding and activation of the human plasma kinin-forming system on the cell walls of Candida albicans and Candida tropicalis

Bacterial infections often upregulate the plasma kinin-forming cascade of the host (the 'contact system') which is triggered by adsorption of high molecular mass kininogen (HK), coagulation factor XII (FXII) and prekallikrein (pHPK) on the host or pathogen cell surfaces. A possible activation of the contact system upon infection of the human host by major fungal pathogens of Candida species has not been extensively explored until a recent report of tight binding of HK to the cell walls of these fungi. In the current study, the adsorption of the other contact system components to the cell surfaces of Candida albicans and Candida tropicalis was characterized. FXII was found to be tightly bound by Candida germ tube forms, to a level 5-fold higher than that for HK. In contrast, pHPK bound poorly but its additional amounts could dock to the cell wall through the surface-bound HK. It was also shown that within the complex of these proteins assembled on the cell walls of fungal hyphae, pHPK could be activated by FXIIa and the active HPK effectively produced kinins from HK. It is suggested that kinins, released at the Candida cell wall, can promote host colonization by the pathogen and the development of infection.