Candida Albicans Antigen Research Articles

Intralesional Vitamin D Injection May Be an Effective Treatment Option for Warts.

Plantar warts are typically resistant to treatment. In recent years, treatments have included administration of intralesional tuberculin; measles, mumps, rubella vaccine; and Candida albicans antigen immunotherapy. To the best of our knowledge, there are no reports of intralesional vitamin D administration for the treatment of warts. To evaluate the efficacy and safety of intralesional vitamin D treatment for plantar warts. Twenty patients with single or multiple plantar warts were included in this study. Vitamin D(3) (0.2 mL, 7.5 mg/mL) was injected into the base of the warts after prilocaine (0.1 mL, 20 mg/mL) injection. A maximum of 5 warts were treated in 1 session, with at maximum 2 injections performed at 4-week intervals. In total, 16 of 20 patients (80%) showed complete resolution of warts, and 1 patient showed partial resolution. Three patients failed to show any response. No recurrence or serious adverse effects were observed. Intralesional vitamin D(3) may be an effective treatment option for warts.

IL-17/IL-10 double-producing T cells: new link between infections, immunosuppression and acute myeloid leukemia.

BackgroundAcute myeloid leukemia (AML) is an incurable disease with fatal infections or relapse being the main causes of death in most cases. In particular, the severe infections occurring in these patients before or during any treatment suggest an intrinsic alteration of the immune system. In this respect, IL-17-producing T helper (Th17) besides playing a key role in regulating inflammatory response, tumor growth and autoimmune diseases, have been shown to protect against bacterial and fungal pathogens. However, the role of Th17 cells in AML has not yet been clarified.MethodsT cell frequencies were assessed by flow cytometry in the peripheral blood of 30 newly diagnosed AML patients and 30 age-matched healthy volunteers. Cytokine production was determined before and after culture of T cells with either Candida Albicans or AML blasts. Statistical analyses were carried out using the paired and unpaired two-tailed Student’s t tests and confirmed with the non parametric Wilcoxon signed-rank test.ResultsA strong increase of Th17 cells producing immunosuppressive IL-10 was observed in AML patients compared with healthy donors. In addition, stimulation of AML-derived T cells with a Candida albicans antigen induced significantly lower IFN-γ production than that observed in healthy donors; intriguingly, depletion of patient Th17 cells restored IFN-γ production after stimulation. To address the role of AML blasts in inducing Th17 alterations, CD4+ cells from healthy donors were co-cultured with CD33+ blasts: data obtained showed that AML blasts induce in healthy donors levels of IL-10-producing Th17 cells similar to those observed in patients.ConclusionsIn AML patients altered Th17 cells actively cause an immunosuppressive state that may promote infections and probably tumor escape. Th17 cells could thus represent a new target to improve AML immunotherapy.

Immunoproteomic analysis of antibody response to cell wall-associated proteins of Candida tropicalis.

This study was conducted to identify antigenic proteins of Candida tropicalis that are targeted by the host immune system. An immunoproteomic approach was used to discover antigens from cell wall of C. tropicalis that were recognized by sera from experimentally infected mice. This resulted in the identification of twelve distinct proteins, of which ten have been previously reported as antigens of Candida albicans. For the remaining two proteins, Idh2p has been described as an antigen of Candida parapsilosis, whereas Kgd2p is revealed for the first time as an antigenic protein for Candida species. These two antigens were expressed as recombinant proteins in Escherichia coli and were shown to be specifically recognized by sera from infected host on Western blot. The present work investigated immunoproteome of C. tropicalis and identified several biomarker candidate antigens, with Kgd2p as a novel immunogenic protein that could be associated with pathogenesis of C. tropicalis. Findings from this study help to improve current understanding on host response to C. tropicalis infection and provide new insights into immune-pathogenesis of C. tropicalis. Besides, the immunogenic proteins could be considered as targets for the development of immunodiagnostic assay and/or vaccine.

The study of the therapeutic action of the cell-associated antigens of candida albicans and candida tropicalis fungi

Fungi of Candida genus are the most widespread causative agent of fungal infections. Candida causes a wide range of infections: from insignificant diseases of the skin and mucous membranes to invasion processes that can practically destroys all organs. Development of a vaccine against candidiasis is the topical issue of modern pharmacy and medicine. Suspensions of cells of Candida albicans and Candida tropicalis fungi were subjected to the action of ultrasound, then filtered through a “Vladipore” membrane MFA-MA No.3 providing separation of the biological material with the size of 10 kDa and its concentration. Then prefiltration and sterilizing filtration were carried out. The resulting purified antigens of Candida albicans fungi cells with the protein concentration of 3 mg/ml and Candida tropicalis with the protein concentration of 5 mg/ml were mixed in the ratio of 1:1 using a mixer with the rotation speed of 100 rpm for 10 min. In the experiment two-month white mice with the body weight of 18-22 g were used; there were 6 animals in the control and test groups. The animals were infected intraperitoneally with the suspension of Candida albicans in the amount of 20 mln of cells and Candida tropicalis in the amount of 60 mln of cells in the volume of 1 ml. In 5 days the cell-associated antigens of Candida fungi in the volume of 0.2 ml were injected intramuscularly to mice in the upper part of the rear right paw. In 14 days the procedure was repeated. The animals of the control group were injected with the sterile 0.9% isotonic saline solution. After that in 14 days the animals were examined and the results were determined. According to the research results it has been found that the cell-associated antigens of Candida albicans and Candida tropicalis provide the therapeutic effect in 100% of animals when injected intramuscularly in the volume of 0.2 ml.

Altered immune responses in patients with chronic mucocutaneous candidiasis

The purpose of this study was to investigate the lymphocyte transformation responses and cytokine secretion of peripheral blood mononuclear cells (PBMC) from patients with chronic mucocutaneous candidiasis (CMC). Phytohaemagglutinin (PHA) mitogen and Candida albicans (C. albicans) antigen proliferation assays were performed by culturing PBMCs in RPMI 1640. The levels of interleukin (IL)-2, IL-10, IL-17 and interferon (IFN)-γ present in the supernatant of cultures were determined using enzyme-linked immunosorbent assay (ELISA). The results showed that most patients (92.3%) had a low proliferative response to C. albicans antigens and PHA. PBMCs from CMC patients produced lower levels of T (h)-1 cytokines IL-2 (78.5±59.8 pg/mL) and IFN-γ (115.1±43.3 pg/mL) in response to Candida antigens when compared to controls (Il-2: 177±103.6 pg/mL; IFN-γ: 330.3±21.6 pg/mL) (P<0.05). Conversely, we observed a partial enhancement of IL-10 in the patients (213.7±86.1 pg/mL). Production of IL-17 indicated no significant differences between patients and controls when stimulated by Candida antigens (21.5±8.6 pg/mL versus 32.4±12.2 pg/mL) and PHA (27.7±11.5 pg/mL versus 36.2±9.1 pg/mL), respectively. These findings suggest that Candida antigens trigger a Th2 instead of Th1 cytokine response in patients with CMC. For better understanding, further studies require on a larger number of patients into the future.

Identification of immunogenic proteins of Candida parapsilosis by serological proteome analysis

Systemic candidiasis is the leading fungal bloodstream infection, and its incidence has been on the rise. Recently, Candida parapsilosis has emerged as an increasingly prevalent fungal pathogen, but little is known about its antigenic profile. Hence, the current work was performed to discover immunogenic proteins of C. parapsilosis using serological proteome analysis. Cell wall proteins extracted from C. parapsilosis were resolved by two-dimensional electrophoresis followed by immunoblotting using antisera from experimentally infected mice. Mass spectrometry analysis of the 32 immunoreactive protein spots resulted in the identification of 12 distinct proteins. Among them, 11 proteins were known antigens of Candida albicans, whereas Idh2p was identified for the first time as an immunogenic protein of Candida species. Recombinant Idh2p was expressed in Escherichia coli, and its antigenicity was verified by immunoblot analysis. An immunoproteomic approach was successfully applied to identify immunogenic proteins of C. parapsilosis, with Idh2p as a novel candidate antigen. The identified antigens may serve as potential biomarkers for development of diagnostic assay and/or vaccine for C. parapsilosis. This work represents the first immunoproteomic analysis of C. parapsilosis, which provides new insights into host-pathogen interactions and pathogenesis of C. parapsilosis. The immunogenic proteins could be studied as biomarker candidates for C. parapsilosis.

Assessment of allergenicity to fungal allergens of Rohtak city, Haryana, India.

Fungal spores are known as one of the important bioparticles causing allergic manifestation in human beings. Hence, knowledge of season and prevalence of the airborne allergens to which the patients are exposed is a prerequisite for proper diagnosis and treatment of allergic disorders in hypersensitive individuals. Keeping this in view, aerial survey was performed in the atmosphere of Rohtak city for 2 consecutive years (March 2008–February 2010), using a volumetric petri plate sampler. A total of 45 fungal spore types were recorded during the survey period. In the present study, February–April and July–November were identified as the peak seasons for Rohtak city. Cladosporium was the main contributor to the total fungal load with 25.14% followed by Alternaria (18.05%), Aspergillus niger (7.66%), Curvularia (5.31%), and Epicoccum (5.29%). Fifteen dominant viable fungal spore types were represented in the form of a fungal calendar. An attempt has also been made to assess the allergenicity of some of the fungal types recorded from the atmosphere of Rohtak city. The magnitude of variations observed in markedly positive skin reactions (2+ and above) varied from 17.3 to 2.3%. Penicillium oxalicum showed a markedly positive reaction in maximum number of patients (26; 17.3%) followed by Rhizopus nigricans (23; 15.3%). ELISA was performed with the sera of patients showing markedly positive skin reactions and the sera were classified into four groups based on percent binding. The majority of the sera showed 0–15% binding to different antigenic extracts, while sera showing >60% binding were least in number. Greater than 30% binding was observed against antigens of Rhizopus nigricans, Epicoccum purpurascens, Penicillium oxalicum, Curvularia lunata, Aspergillus flavus, Candida albicans and Neurospora sitophila. The concordance between positive skin reaction and serum-specific IgE antibodies ranged from 16.7 to 69.2%.

Humoral immunity and delayed-type hypersensitivity in healthy subjects treated for 30days with MK-7123, a selective CXCR2 antagonist

Antagonism of the chemokine receptor CXCR2 inhibits neutrophil trafficking and may thus be therapeutic in patients with chronic obstructive pulmonary disease and other lung disorders in which there is substantial infiltration by neutrophils. Here, we report the findings from a randomized, placebo-controlled, double-blind clinical trial of the small-molecule CXCR2 antagonist MK-7123 (formerly SCH 527123) that evaluated potential downstream effects of CXCR2 antagonism on immunogenic competency (B cell antibody response) in the adaptive immune system and delayed-type hypersensitivity (DTH) in healthy subjects (ages 34-65 years) dosed once daily for 30 days either with 30 mg MK-7123 (n=24) or placebo (n=7). Eligible subjects were seronegative for anti-hepatitis A virus (HAV) immunoglobulin G (IgG) and positive for DTH response to intradermal injection of Candida albicans antigen at screening. Subjects were vaccinated for HAV on treatment Day 2. The primary endpoints were anti-HAV IgG titer on Day 30 and DTH response magnitude on Day 27. Pharmacokinetic and safety endpoints were also assessed. We observed that anti-HAV IgG titers and DTH responses did not differ significantly between MK-7123-treated and placebo-treated subjects. Twenty-eight days postvaccination, seroconversion (anti-HAV IgG titer≥10mIU/mL) was observed in 87.5% and 85.7% of MK-7123-treated and placebo-treated subjects, respectively; mean (±SE) titers were 27.3±5.5 and 21.4±4.3mIU/mL, respectively. Treatment with MK-7123 was generally well tolerated. Doses were followed by temporary reductions in absolute peripheral blood neutrophil count. In conclusion, this study found that B cell response and cell-mediated immunity were not altered by CXCR2 antagonism with MK-7123.

Establishment and preliminary evaluation of a rapid detection method for germ tube-specific antigens of Candida albicans

Objective To establish a double-antibody sandwich enzyme linked immunosorbent assay (DAS-ELISA) for the rapid detection of germ tube-specific antigens of Candida albicans,and to evaluate its specificity and sensitivity.Methods A DAS-ELISA was established with the monoclonal antibody McAb03.2C1-C2 as the primary antibody,and horseradish peroxidase (HRP) labeled McAb03.2C1-C2 as the secondary antibody.The established assay was used to detect germ tube-specific antigens of Candida albicans in sera from 5 patients with systemic Candida albicans infection and from 6 rabbit models at 12,24,48,72hours,on week 1,2 after infection with Candida albicans.Results A good liner relationship was observed between the absorbance value at 495 nm and antigen concentrations when the titer of McAb03.2C1-C2 was 1 ∶ 4000 and the concentration of coated antigen varied from 1.25 to 40 μg/ml.The specificity and sensitivity of the DAS-ELISA were 95％ and 92％ respectively in the detection of germ tube-specific antigens in the rabbit models.The results of detection with DAS-ELISA in serum specimens from the patients were consistent with those with the routine method.Conclusions A DAS-ELISA is primarily established for the rapid detection of germ tube-specific antigens of Candida albicans,and has shown a satisfactory sensitivity and specificity in the animal model experiment. Key words: Candida albicans; Antibodies, monoclonal; Enzyme-linked immunosorbent assay; Sensitivity and specificity

T-helper Cell-Mediated Proliferation and Cytokine Responses against Recombinant Merkel Cell Polyomavirus-Like Particles

The newly discovered Merkel Cell Polyomavirus (MCPyV) resides in approximately 80% of Merkel cell carcinomas (MCC). Causal role of MCPyV for this rare and aggressive skin cancer is suggested by monoclonal integration and truncation of large T (LT) viral antigen in MCC cells. The mutated MCPyV has recently been found in highly purified leukemic cells from patients with chronic lymphocytic leukemia (CLL), suggesting a pathogenic role also in CLL. About 50–80% of adults display MCPyV-specific antibodies. The humoral immunity does not protect against the development of MCC, as neutralizing MCPyV antibodies occur in higher levels among MCC patients than healthy controls. Impaired T-cell immunity has been linked with aggressive MCC behavior. Therefore, cellular immunity appears to be important in MCPyV infection surveillance. In order to elucidate the role of MCPyV-specific Th-cell immunity, peripheral blood mononuclear cells (PBMC) of healthy adults were stimulated with MCPyV VP1 virus-like particles (VLPs), using human bocavirus (HBoV) VLPs and Candida albicans antigen as positive controls. Proliferation, IFN-γ, IL-13 and IL-10 responses were examined in 15 MCPyV-seropositive and 15 seronegative volunteers. With the MCPyV antigen, significantly stronger Th-cell responses were found in MCPyV-seropositive than MCPyV-seronegative subjects, whereas with the control antigens, the responses were statistically similar. The most readily detectable cytokine was IFN-γ. The MCPyV antigen tended to induce stronger IFN-γ responses than HBoV VLP antigen. Taken together, MCPyV-specific Th-cells elicit vigorous IFN-γ responses. IFN-γ being a cytokine with major antiviral and tumor suppressing functions, Th-cells are suggested to be important mediators of MCPyV-specific immune surveillance.

Effect of Nocardia on immune response of Heat Killed Candida albicans Antigen against systemic candidiasis

This study was undertaken to prepare Heat Killed Candida albicans Antigen (HK-CA) and to investigate it's effect on elicitation of Delayed-type Hypersensitivity (DTH) and protection from virulent Candida challenged in mice, and described the major effect of Nocardia on the immunogenicity of this Ag.Four groups of 6 males Swiss mice for each group were immunized intraperitonialy(I.p)for 10 days at 5 doses(one day intervals) with 1x108 HK-CA plus Nocardia cell sap as adjuvant(CFA),the second group immunized with HK-CA plus Freund incomplete adjuvant,the third group immunized with HK-CA only and the fourth group treated with normal saline. Another group of 6 animals was immunized intranasally(I.n)with HK-CA only with the same doses as previously.Two weeks following the last application of Ag,50% of animals(3 for each group) were challenged intravenously(I.v)with 106 viable C.albicans to assess the protection rate.and the other 50% of mice were used to evaluate the development of DTH response in each immunization methods.Greatly percentage survival was observed when mice immunized with HK-CA plus CFA,which challenged with 106 live C. albicans in comparison with other groups.And also all animals of the 1st group developed highly significant DTH response which was supporyed by marked infiltration and aggregation of lymphocyte in some internal organs that indicate it's intensive involvement in immune response,while in the other groups,mononuclear cells infiltration were present with moderate to less intensive. Clearly,HK-CA in conjunction with Nocardia cell sap as adjuvant afforded significant levels of protection,Furthermore,the noval approach of I.n immunization could used for the development of an effective vaccine

Alteration of Th17 and Treg cell subpopulations co-exist in patients affected with systemic sclerosis

Aim of the study has been to understand the relationship between TH17 and Treg cell subsets in patients affected with systemic sclerosis (SSc). Phenotypes and functions of Th17 and Treg cell subsets were analyzed in a series of 36 SSc patients. Th17 cell concentration in the peripheral blood was found to be increased in SSc patients with respect to healthy controls independently from type or stage of disease. After PBMC stimulation with a polyclonal stimulus or Candida albicans antigens the frequency of Th17 T cell clones was significantly higher in SSc patients with respect to controls suggesting the skewing of immune response in SSc patients toward Th17 cell generation/expansion. Concerning the Treg compartment, both CD4+CD25+ and CD8+CD28- Treg subsets showed quantitative and qualitative alteration in the peripheral blood of SSc patients. Collectively, these data highlight the existence of an imbalanced ratio between Th17 and Treg cell subsets in SSc patients.

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.

Optimization of storage and shipment of cryopreserved peripheral blood mononuclear cells from HIV-infected and uninfected individuals for ELISPOT assays

Functional immunologic assays using cryopreserved peripheral blood mononuclear cells (PBMC) are influenced by blood processing, storage and shipment. The objective of this study was to compare the viability, recovery and ELISPOT results of PBMC stored and shipped in liquid nitrogen (LN/LN) or stored in LN and shipped on dry ice (LN/DI) or stored at −70 °C for 3 to 12 weeks and shipped on DI (70/DI 3 to 12); and to assess the effect of donor HIV infection status on the interaction between storage/shipment and the outcome measures. PBMC from 12 HIV-infected and 12 uninfected donors showed that LN/LN conferred higher viability and recovery than LN/DI or 70/DI 3, 6, 9 or 12. LN/DI PBMC had higher viability than any 70/DI PBMC. The PBMC viability and recovery linearly decreased with the duration of storage at −70 °C from 3 to 12 weeks. This effect was more pronounced in samples from HIV-infected than uninfected donors. Results of ELISPOT assays using CMV pp65, CEF and Candida albicans antigens were qualitatively and quantitatively similar across LN/LN, LN/DI and 70/DI 3. However, ELISPOT values significantly decreased with the duration of storage at −70 °C both in HIV-infected and uninfected donors. ELISPOT results also decreased with PBMC viability < 70%.

The use of hybrid phage displaying antigen epitope and recombinant protein in the diagnosis of systemic Candida albicans infection in rabbits and cancer patients

Hsp90 and Sap2 are 2 immunodominant antigens of Candida albicans. Both of them can induce the production of antibody. In this article, systemically infected rabbits were used to study the Hsp90 and Sap2 antibody production. Also, pET28a–Hsp90 protein, pET28a–Sap2 protein, hybrid phage displaying LKVIRK epitope, and hybrid phage displaying VKYTS epitope were used for diagnosis of the antibody in cancer patients. The results showed that the Sap2 antibody appeared earlier than Hsp90 antibody in systemically infected rabbits. Meanwhile, both of the antibodies can perform protection in rabbits. The conclusion is that Sap2 antibody, which appears at early stage in systemic candidiasis, may be better than Hsp90 antibody for the diagnosis of invasive candidiasis. For 141 sera of cancer patients, 52 sera were detected Sap2 antibody and 57 sera were detected Hsp90 antibody. Only 14 sera contained both the 2 antibodies. Although recombinant protein was slightly more sensitive than hybrid phage, there was no significant difference between them. For its easy preparation, less expensive hybrid phage displaying antigen epitope may be a better agent for diagnosis of candidiasis.

Chronic mucocutaneous candidiasis in APECED or thymoma patients correlates with autoimmunity to Th17-associated cytokines

Chronic mucocutaneous candidiasis (CMC) is frequently associated with T cell immunodeficiencies. Specifically, the proinflammatory IL-17A–producing Th17 subset is implicated in protection against fungi at epithelial surfaces. In autoimmune polyendocrinopathy candidiasis ectodermal dystrophy (APECED, or autoimmune polyendocrine syndrome 1), CMC is often the first sign, but the underlying immunodeficiency is a long-standing puzzle. In contrast, the subsequent endocrine features are clearly autoimmune, resulting from defects in thymic self-tolerance induction caused by mutations in the autoimmune regulator (AIRE). We report severely reduced IL-17F and IL-22 responses to both Candida albicans antigens and polyclonal stimulation in APECED patients with CMC. Surprisingly, these reductions are strongly associated with neutralizing autoantibodies to IL-17F and IL-22, whereas responses were normal and autoantibodies infrequent in APECED patients without CMC. Our multicenter survey revealed neutralizing autoantibodies against IL-17A (41%), IL-17F (75%), and/ or IL-22 (91%) in >150 APECED patients, especially those with CMC. We independently found autoantibodies against these Th17-produced cytokines in rare thymoma patients with CMC. The autoantibodies preceded the CMC in all informative cases. We conclude that IL-22 and IL-17F are key natural defenders against CMC and that the immunodeficiency underlying CMC in both patient groups has an autoimmune basis.

Evaluation of Candida albicans allergens reactive with specific IgE in asthma and atopic eczema patients

Candida albicans (C.albicans) produces important allergenic components which can induce allergic reactions in sensitised patients. The purpose of this study was to extract the C.albicans antigens for evaluating the specific anti-Candida IgE in sera of atopic eczema (AE) and asthmatic patients (AS). 95 AE, 85 AS, and 70 non-atopic cases were selected with sequential trials. Candida albicans antigens were prepared and then skin prick test (SPT), ELISA and IgE-immunoblotting tests were performed for all patients. Positive SPT reactions were obtained on 52.6% of AE and 54.1% of AS patients and 4.3% of healthy controls (P < 0.05). Using ELISA, specific anti-C. albicans IgE antibody was detected in 32.6% and 41.2% of patients with AE and AS, respectively. No specific IgE antibody was detected in healthy controls (P < 0.05). In SDS-PAGE, protein bands with molecular weights between 13 and 135 kDa were detected, and some of them reacted with specific IgE in immunoblotting. In AE patients, the most important allergenic components were 25, 34, and 57 kDa protein bands, whereas in AS, 22, 25, and 34 kDa protein bands were observed as major allergens. Candidaalbicans produces different allergenic components that can induce allergic reactions and may be pathogenetically important in patients with AE and AS.

Antibody response to the 45 kDa Candida albicans antigen in an animal model and potential role of the antigen in adherence

The Candida antigen CR3-RP (complement receptor 3-related protein) is supposed to be a 'mimicry' protein because of its ability to bind antibody directed against the alpha subunit of the mammalian CR3 (CD11b/CD18). This study aimed to (i) investigate the specific humoral isotypic response to immunization with CR3-RP in vivo in a rabbit animal model, and (ii) determine the role of CR3-RP in the adherence of Candida albicans in vitro using the model systems of buccal epithelial cells (BECs) and biofilm formation. The synthetic C. albicans peptide DINGGGATLPQ corresponding to 11 amino-acids of the CR3-RP sequence DINGGGATLPQALXQITGVIT, determined by N-terminal sequencing, was used for immunization of rabbits to obtain polyclonal anti-CR3-PR serum and for subsequent characterization of the humoral isotypic response of rabbits. A significant increase of IgG, IgA and IgM anti-CR3-RP specific antibodies was observed after the third (P<0.01) and the fourth (P<0.001) immunization doses. The elevation of IgA levels suggested peptide immunomodulation of the IgA1 subclass, presumably in coincidence with Candida epithelial adherence. Blocking CR3-RP with polyclonal anti-CR3-RP serum reduced the ability of Candida to adhere to BECs, in comparison with the control, by up to 35 % (P<0.001), and reduced biofilm formation by 28 % (P<0.001), including changes in biofilm thickness and integrity detected by confocal laser scanning microscopy. These properties of CR3-RP suggest that it has potential for future vaccine development.

Synthesis and Immunochemical characterization of S‐linked Glycoconjugate Vaccines against Candida albicans

Replacement of the glycosidic oxygen atom by a sulphur atom is a promising technique for creating glycoconjugates with increased resistance to hydrolysis by endogenous glycosidases. The synthesis and antigenic properties of two distinct (1-->2)-beta-mannan trisaccharides with inter residue-S-linked mannopyranose residues are described. Syntheses were based on an oxidation-reduction strategy to construct the O-linked beta-mannopyranoside bonds and a SN2 inversion to provide 1-thio-beta-mannopyranoside residues. Subsequently the allyl trisaccharide glycosides were subjected to photo addition with cysteine amine and coupled to tetanus toxoid and bovine serum albumin with good efficiency via an adipic acid tether. Rabbit immunization studies revealed that the antibodies elicited by the two glycoconjugates were able to recognize the corresponding O-linked trisaccharide epitope conjugated to BSA and the native cell wall antigen of Candida albicans.

Antigen-presenting capacity of macrophages and dendritic cells in the peritoneal cavity of patients treated with peritoneal dialysis.

In this study the antigen-presenting capacity of human peritoneal cells and the influence of continuous ambulant peritoneal dialysis (CAPD) were studied. On average 6% of the peritoneal cells were dendritic cells (DC), with no difference between CAPD and control peritoneal cells. DC were enriched by selecting for non-adherent, Fc receptor-negative, low density cells. A typical spot-like CD68 positivity was seen in DC, in contrast to the pancytoplasmic staining pattern in macrophages. Peritoneal DC morphologically and functionally showed features of cells belonging to the DC lineage. Peritoneal DC were superior antigen-presenting cells for both allo-antigen, and Candida albicans antigen or purified protein derivative. CAPD peritoneal macrophages were two- to three-fold better stimulator cells for allogeneic T cells compared with control macrophages. The level of integrins/adhesins or MHC class I or II, as measured semi-quantitatively on the FACS, could not account for this phenomenon. In addition, a double chamber system showed that dialysate-activated macrophages produced soluble factors that could enhance DC-induced allogeneic T cell proliferation. In conclusion, human peritoneal cells contain a relatively high percentage of classical DC. CAPD treatment does not impair the antigen-presenting capacity of peritoneal cells, but instead upregulates the allo-antigen-presenting capacity of peritoneal macrophages.