The diagnostic and therapeutic potential of a monoclonal antibody to the 60-kilodalton nuclear antigen of Candida albicans

A monoclonal antibody CWE4 was produced against the 60-kilodalton (kDa) antigen of Candida albicans. Previously we demonstrated that antibody to this antigen was the second most commonly produced in patients with systemic candidiasis. Immunoelectron microscopy demonstrated reactivity of CWE4 with a nuclear component in yeast and mycelial cells. It was a high affinity IgG immunoglobulin. CWE4 was incorporated in a dot immunobinding assay to detect circulating 60 kDa antigen in sera from patients with systemic candidiasis. It was much more sensitive than reverse passive latex agglutination (RPLA), being positive in 69% of neutropenic patients and 80% of non-neutropenic patients, compared to 33% and 68% respectively with RPLA. False positives were rare among uninfected controls but common among superficially infected and colonized patients. In a mouse model of candidal peritonitis, CWE4 compared unfavourably with a rabbit hyperimmune candidal antiserum in its ability to reduce the severity of infection.     

Increased serum and salivary immunoglobulins against Candida albicans in HIV-infected patients with oral candidiasis.

The aim of this study was to explore anti-Candida albicans systemic and mucosal humoral responses against Candida virulence antigens such as somatic antigen and secreted aspartic proteases (Saps) in HIV-infected patients with oral candidiasis. Twenty-eight subjects were included in the study: 11 HIV-positive patients without oral candidiasis (group A), 6 HIV-positive patients with oral candidiasis (group B) and 11 HIV-negative healthy controls (group C). Total IgA, IgG and IgM concentrations and antibodies to C. albicans (somatic antigen, Sap1, Sap6) were measured in serum and saliva. We developed a time-resolved immunofluorometric assay with biotin and europium-labeled streptavidin for this purpose. Salivary total IgA, IgG and IgM concentrations were higher in group B. IgA, IgG and IgM anti-C. albicans antibodies (against somatic antigen, Sap1, Sap6) were higher in saliva and serum from patients from group B compared with patients from group A and controls. Our results suggest that, in oral candidiasis, HIV-infected patients have a high mucosal response, specifically directed against C. albicans virulence antigens, such as somatic antigen, Sap1 and Sap6.     

Immunodiagnosis of systemic aspergillosis. I. Antigenemia detected by radioimmunoassay in experimental infection.

Because systemic aspergillosis is difficult to diagnose ante mortem, a study to improve immunodiagnosis was undertaken in a rabbit model of disseminated infection. We found that the predominant humoral response of infected animals was directed against four Aspergillus antigens identified by crossed immunoelectrophoresis. One of these antigens, a cell-wall carbohydrate, was purified by gel-filtration chromatography and was used to develop a radioimmunoassay. The sensitivity of this assay was increased by testing for serum-bound antigen as well as for free antigen. When the sensitivity of the RIA was evaluated in the animal model, antigenemia was detected in 78% of 51 rabbits with disseminated infection and ante morten in 85% of 42 rabbits with lethal infection. By contrast, with immunoprecipitin analysis only eight of 51 rabbits were positive for antigen, and six of 51 rabbits were positive for Aspergillus antibody. The specificity of the RIA was also tested. Negative controls for antigen included sera from 76 normal rabbits and sera from 25 rabbits with systemic candidiasis. The Candida control group is pertinent because 48% of these rabbits had specific Candida antigenemia detected by a mannan RIA. This study demonstrates that Aspergillus antigenemia occurs during the course of experimental disseminated aspergillosis and illustrates the potential of an Aspergillus antigen RIA for sensitive, specific immunodiagnosis of human infections.     

Mannan antigenemia in the diagnosis of invasive Candida infections.

Because it is often difficult to diagnose invasive Candida infections, a sensitive hemagglutination inhibition assay to detect the surface antigen, mannan, was developed. Mannan antigenemia was detected early in the course of infection in 4 of 14 patients with systemic candidiasis and 2 of 5 patients with invasive gastrointestinal candidiasis. Mannan was not detected in 48 patients with noninvasive Candida or other systemic mycotic infections or in 99% of 234 patients in other control groups. Mannan antibodies were almost universally present in both candidiasis and control groups. In four patients with systemic candidiasis, an early period of mannan antigenemia was followed by a rapid rise in mannan antibody titer. These findings suggest that antemortem diagnosis would be improved in one-third of cases of invasive Candida infection detected by the hemagglutination inhibition assay. A positive test for serum mannan would be an early and specific signal of invasive disease.     

Specific inhibition of in vitro Candida-induced lymphocyte proliferation by polysaccharidic antigens present in the serum of patients with chronic mucocutaneous candidiasis.

A specific inhibitory activity of in vitro proliferative responses of normal human lymphocytes to Candida metabolic antigen was found in the serum of 6 out of 23 children with chronic mucocutaneous candidiasis. In each of the six patients, the presence of an inhibitory activity was associated with Candida-specific cellular defects, characterized by a negative-skin test and a lack of in vitro lymphocyte proliferation. The presence of a circulating inhibitor was detected during relapses of the disease and disappeared under antifungal therapy. This inhibitory effect was not associated with any toxicity on tested lymphocytes. The factor was shown to be nondialysable, thermostable, nonprecipitable with ammonium sulfate and absorbable on anti-Candida antibodies or concanavalin A-coupled agarose columns. Altogether, these results suggest that the inhibitory factor is not an immunoglobulin, but rather a polysaccharidic antigen of Candida albicans. An inhibition of Candida-induced proliferative response of normal human lymphocytes was also obtained by addition of polysacharide antigens or purified mannans from C. albicans to cultures. Candida polysaccharidic antigens appeared, therefore, to be involved in specific depression of cellular functions observed in chronic candidiasis.     

Serologic analysis of antigen-specific reactivity in patients with systemic candidiasis

Antibody responses to candidal polypeptides and mannans were studied in patients with systemic candidiasis, candiduria, and other fungal and bacterial infections, and in healthy laboratory personnel to determine the diagnostic value of these immunologic responses. When tested by immunoblot analysis, sera from 15 patients with systemic candidiasis frequently contained antibodies to three antigens: 15 of 15 sera from patients with invasive disease reacted to a molecular species having a molecular weight (Mr of 90-200 kd, 13 of 15 reacted with a 45-kd polypeptide, and 12 of 15 reacted with a 17-kd polypeptide. Lesser reactivity was observed in 11 of 15 sera with a 28-kd candidal antigen and in 9 of 15 to a 57-kd candidal antigen. Quantitation of antibody titers against the 45-kd candidal polypeptide demonstrated much higher immunoreactivity in patients with systemic candidiasis than in patients with superficial candidal infections, bacterial infections, other systemic mycoses, and healthy individuals. Antimannan antibody titers were measured by an enzyme-linked immunosorbent assay (ELISA) and these titers were also higher in patients with systemic candidiasis than in patients in the other categories. These differences, however, were less than those observed with the anti-45-kd polypeptide antibody. Therefore, the ability to detect systemic candidiasis is improved by testing sera for immunoreactivity to polypeptide and to mannan antigens from Candida albicans. Detection of polypeptide antibodies improves the serodiagnosis of systemic candidiasis.     

Caspofungin susceptibility testing of isolates from patients with esophageal candidiasis or invasive candidiasis: relationship of MIC to treatment outcome

The caspofungin clinical trial database offers an opportunity to assess susceptibility results for Candida pathogens obtained from patients with candidiasis and allows for correlations between efficacy outcomes and MICs. Candida isolates have been identified from patients enrolled in four studies of esophageal candidiasis and two studies of invasive candidiasis. The MICs of caspofungin for all baseline isolates were measured at a central laboratory using NCCLS criteria (document M-27A); MICs for caspofungin were defined as the lowest concentration inhibiting prominent growth at 24 h. MICs were then compared to clinical and microbiological outcomes across the two diseases. Susceptibility testing for caspofungin was performed on 515 unique baseline isolates of Candida spp. obtained from patients with esophageal candidiasis. MICs for caspofungin ranged from 0.008 to 4 microg/ml; the MIC50 and MIC90 were 0.5 and 1.0 microg/ml, respectively. Susceptibility testing was also performed on 231 unique baseline isolates of Candida spp. from patients with invasive candidiasis. The majority (approximately 96%) of MICs were between 0.125 and 2 microg/ml, with MIC50 and MIC90 for caspofungin being 0.5 and 2.0 microg/ml, respectively. Overall, caspofungin demonstrated potent in vitro activity against clinical isolates of Candida species. A relationship between MIC for caspofungin and treatment outcome was not seen for patients with either esophageal candidiasis or invasive candidiasis. Patients with isolates for which the MICs were highest (>2 microg/ml) had better outcomes than patients with isolates for which the MICs were lower (<1 microg/ml). Additionally, no correlation between MIC and outcome was identified for specific Candida species.     

Antifungal activities of R-135853, a sordarin derivative, in experimental candidiasis in mice

The activities of R-135853, a novel sordarin derivative that possesses a 1,4-oxazepane ring moiety, were evaluated in vitro and in vivo. R-135853 exhibited potent in vitro activities against Candida albicans (fluconazole-susceptible strains), Candida glabrata, Candida tropicalis, and Cryptococcus neoformans, with MICs at which 90% of isolates were inhibited of 0.03, 1, 0.5, and 0.5 microg/ml, respectively. R-135853 also exhibited potent activities against fluconazole-susceptible dose-dependent and fluconazole-resistant strains of C. albicans, with MICs ranging from 0.03 to 0.06 mug/ml. However, R-135853 exhibited weak or no activity against Candida parapsilosis, Candida krusei, and Aspergillus spp. R-135853 exhibited dose-dependent efficacy against experimental murine hematogenous candidiasis induced by C. albicans when it was administered by both the subcutaneous and the oral routes and reduced viable cell counts in the kidneys significantly when it was administered at 50 mg/kg of body weight/dose (administration three times a day). In this model, R-135853 also exhibited dose-dependent efficacy by single oral administration. Subcutaneous administration of R-135853 exhibited dose-dependent efficacy against experimental murine esophageal candidiasis induced by fluconazole-resistant C. albicans, against which fluconazole at 50 mg/kg/dose was ineffective, and reduced viable cell counts in the esophagus significantly when it was administered at 10 and 50 mg/kg/dose. R-135853 eradicated C. albicans from the esophagi of one and four of five mice when it was administered at 10 and 50 mg/kg/dose, respectively. These results suggest that R-135853 is promising for the treatment of disseminated or mucosal candidiasis, including fluconazole-refractory infections.     

In vitro and in vivo antifungal activities of T-2307, a novel arylamidine

The in vitro and in vivo antifungal activities of T-2307, a novel arylamidine, were evaluated and compared with those of fluconazole, voriconazole, micafungin, and amphotericin B. T-2307 exhibited broad-spectrum activity against clinically significant pathogens, including Candida species (MIC range, 0.00025 to 0.0078 microg/ml), Cryptococcus neoformans (MIC range, 0.0039 to 0.0625 microg/ml), and Aspergillus species (MIC range, 0.0156 to 4 microg/ml). Furthermore, T-2307 exhibited potent activity against fluconazole-resistant and fluconazole-susceptible-dose-dependent Candida albicans strains as well as against azole-susceptible strains. T-2307 exhibited fungicidal activity against some Candida and Aspergillus species and against Cryptococcus neoformans. In mouse models of disseminated candidiasis, cryptococcosis, and aspergillosis, the 50% effective doses of T-2307 were 0.00755, 0.117, and 0.391 mg.kg(-1).dose(-1), respectively. This agent was considerably more active than micafungin and amphotericin B against candidiasis and than amphotericin B against cryptococcosis, and its activity was comparable to the activities of micafungin and amphotericin B against aspergillosis. The results of preclinical in vitro and in vivo evaluations performed thus far indicate that T-2307 could represent a potent injectable agent for the treatment of candidiasis, cryptococcosis, and aspergillosis.     

Clinical efficacy and safety of intravenous itraconazole in the management of invasive candidiasis in patients of surgery and critical care

Although itraconazole exhibits potent activity against Candida species, there have been few studies examining the use of intravenous itraconazole in the treatment of invasive candidiasis. A nationwide multicenter clinical study was conducted to evaluate the efficacy and safety of intravenous itraconazole in the management of invasive candidiasis, including non-albicans Candida species, in non-neutropenic patients undergoing surgery and critical care. Between September 2007 and August 2009, patients with proven and presumed candidiasis were enrolled at 22 participating institutions. Patients with presumed candidiasis had a deep-body temperature of 37.8°C or higher and were positive for serum β-D: -glucan or two or more colonization sites of Candida species. The main exclusion criterion was severe renal impairment (creatinine clearance <30 ml/min). The primary efficacy analysis was based on clinical and microbiological responses 5-10 days after the end of treatment, assessed by an independent data review committee. Of the 60 patients enrolled, 49 were included in the modified intention-to-treat population; 31 patients received a definitive diagnosis and 18 patients a presumed diagnosis. Intravenous itraconazole was used as first-line therapy to treat 39 patients and as second-line therapy for 10 patients. The isolated species included Candida albicans (25 strains with definitive diagnosis and 17 with presumed diagnosis) and non-albicans species (16 and 10, respectively). Treatment was successful in 61.5% patients (65.5% in first-line and 50.0% in second-line therapy); 60% of proven invasive candidiasis (IC) patients were judged as successful compared with 63.2% of presumed candidiasis patients. Eradication rate was 63.6% for C. albicans and 71.4% for C. glabrata. Adverse effects occurred in 9 of 60 patients (15.0%), commonly impaired liver function. The clinical efficacy and safety of intravenous itraconazole were suggested in the management of proven and presumed candidiasis including C. glabrata in non-neutropenic patients. The status of intravenous itraconazole in the Japanese guideline warrants reconsideration.     

Evaluation of the echinocandin antifungal MK-0991 (L-743,872): efficacies in mouse models of disseminated aspergillosis, candidiasis, and cryptococcosis.

The in vivo activity of the Merck antifungal echinocandin drug candidate MK-0991 (L-743,872) was evaluated in mouse models of disseminated candidiasis, aspergillosis, and cryptococcosis. The echinocandins are potent inhibitors of 1,3-beta-D-glucan synthase. Two models of disseminated candidiasis were used. In a Candida albicans mouse survival model with both DBA/2N and CD-1 mice, estimates of the 50% effective doses (ED50s) of MK-0991 were 0.04 and 0.10 mg/kg of body weight/dose at 21 days after challenge, respectively. In a C. albicans target organ assay (TOA) with DBA/2N mice, MK-0991 at levels of > or =0.09 mg/kg/dose significantly reduced the numbers of C. albicans CFU/g of kidneys compared to the numbers in the kidneys of control mice from 1 to 28 days after challenge. Even when given as a single intraperitoneal dose either 30 min or 24 h after challenge, MK-0991 was effective and significantly reduced the numbers of C. albicans CFU/g of kidney compared to those in the controls. MK-0991 was >300-fold less active when it was administered orally than when it was administered parenterally. MK-0991 was efficacious in mouse TOAs against other C. albicans strains and Candida species including Candida tropicalis, Candida (Torulopsis) glabrata, Candida lusitaniae, Candida parapsilosis, and Candida krusei. MK-0991 was ineffective against disseminated Cryptococcus neoformans infections. In the model of disseminated aspergillosis in mice, MK-0991 at doses of > or =0.02 mg/kg/dose significantly prolonged the survival of DBA/2N mice, with estimates of the ED50 and ED90 of MK-0991 being 0.03 and 0.12 mg/kg/dose, respectively, at 28 days after challenge. MK-0991 is a potent, parenterally administered therapeutic agent against disseminated candidiasis and aspergillosis that warrants further investigation in human clinical trials.     

抗烯醇化酶抗体检测对侵袭性念珠菌病的诊断价值

目的 利用白念珠菌烯醇化酶重组蛋白质为抗原,建立测定人血清中抗白念珠菌烯醇化酶IgG类抗体的ELISA法,评估其在侵袭性念珠菌病(IC)诊断中的应用价值.方法 收集各类确诊IC患者(66例)和白念珠菌定植者(32例)血清,用重组白念珠菌烯醉化酶包被ELISA微孔板,测定血清中的抗烯醇化酶抗体,确定cut off值并对方...     

Esophageal biopsy findings in the acquired immunodeficiency syndrome (AIDS): clinicopathologic correlation in 20 patients

We reviewed 20 esophageal biopsy specimens from 180 adult patients with the acquired immunodeficiency syndrome (AIDS). Ten (50%) showed superficial Candida infection, and four revealed esophagitis due to cytomegalovirus. Candida was never invasive, even though it was associated with significant ulceration. Esophageal candidiasis did not necessarily imply the presence of oral candidiasis, and conversely, oral candidiasis did not imply esophageal candidiasis. Odynophagia was associated with significant histologic ulcerations in eight of ten patients. In the patients who had odynophagia, biopsy was almost equally likely to show Candida or viral cytopathic effect. We discuss the clinicopathologic implications of these findings.     

Detection of candida enolase antibody in patients with candidiasis

The serodiagnostic value of candidaenolase antibody was evaluated in 27 patients with systemic candidiasis. The glycolytic enzyme enolase was prepared from Candida albicans IFM 40009 and used as the antigen for immunoblot assays. IgG class antibody was found in the sera of 17 of 27 patients (62.9%) obtained during the early course of the infection. Serial sampling of sera increased the number of patients with positive Candida enolase antibody, which was detected in 25 of 27 patients (92.5%). None of the patients with localized candidiasis showed a positive IgG titer more than 1:100. The specificity of Candida enolase IgG antibody was 95%. This antibody was observed in various candida species: Candida albicans (6/7, 85.7%); C. parapsilosis (7/9, 77.9%); C. tropicalis (5/5, 100%); C. guilliermondii (4/4, 100%); and C. glabrata (1/3, 33.3%). © 1994 Wiley-Liss, Inc.     

Efficacy of oral E1210, a new broad-spectrum antifungal with a novel mechanism of action, in murine models of candidiasis, aspergillosis, and fusariosis

E1210 is a first-in-class, broad-spectrum antifungal with a novel mechanism of action-inhibition of fungal glycosylphosphatidylinositol biosynthesis. In this study, the efficacies of E1210 and reference antifungals were evaluated in murine models of oropharyngeal and disseminated candidiasis, pulmonary aspergillosis, and disseminated fusariosis. Oral E1210 demonstrated dose-dependent efficacy in infections caused by Candida species, Aspergillus spp., and Fusarium solani. In the treatment of oropharyngeal candidiasis, E1210 and fluconazole each caused a significantly greater reduction in the number of oral CFU than the control treatment (P < 0.05). In the disseminated candidiasis model, mice treated with E1210, fluconazole, caspofungin, or liposomal amphotericin B showed significantly higher survival rates than the control mice (P < 0.05). E1210 was also highly effective in treating disseminated candidiasis caused by azole-resistant Candida albicans or Candida tropicalis. A 24-h delay in treatment onset minimally affected the efficacy outcome of E1210 in the treatment of disseminated candidiasis. In the Aspergillus flavus pulmonary aspergillosis model, mice treated with E1210, voriconazole, or caspofungin showed significantly higher survival rates than the control mice (P < 0.05). E1210 was also effective in the treatment of Aspergillus fumigatus pulmonary aspergillosis. In contrast to many antifungals, E1210 was also effective against disseminated fusariosis caused by F. solani. In conclusion, E1210 demonstrated consistent efficacy in murine models of oropharyngeal and disseminated candidiasis, pulmonary aspergillosis, and disseminated fusariosis. These data suggest that further studies to determine E1210's potential for the treatment of disseminated fungal infections are indicated.     

Effects of caspofungin against Candida guilliermondii and Candida parapsilosis

The in vitro activity of caspofungin (CAS) was investigated against 28 yeast isolates belonging to Candida albicans (n = 5), Candida guilliermondii (n = 10), and Candida parapsilosis (n = 13). CAS MICs obtained by broth dilution and Etest methods clearly showed a rank order of susceptibility to the echinocandin compound with C. albicans > C. parapsilosis > C. guilliermondii. Similarly, time-kill assays performed on selected isolates showed that CAS was fungistatic against C. albicans and C. parapsilosis, while it did not exert any activity against C. guilliermondii. In a murine model of systemic candidiasis, CAS given at doses as low as 1 mg/kg of body weight/day was effective at reducing the kidney burden of mice infected with either C. albicans or C. guilliermondii isolates. Depending on the isolate tested, mice infected with C. parapsilosis responded to CAS given at 1 and/or 5 mg/kg/day. However, the overall CFU reduction for C. guilliermondii and C. parapsilosis was approximately 100-fold less than that for C. albicans. Our study shows that CAS was active in experimental systemic candidiasis due to C. guilliermondii and C. parapsilosis, but this activity required relatively high drug dosages.     

Pharmacological advances in the treatment of invasive candidiasis

Invasive candidiasis is a common nosocomial infection, especially among the critically ill and immunocompromised patient populations. The recent standardization and increasing availability of antifungal susceptibility testing has the potential to optimize the selection of antifungal therapy. Treatment has been revolutionized in recent years with the marketing of several antifungal agents with excellent activity against Candida spp. These agents include the triazoles, fluconazole and voriconazole, and the echinocandin antifungals. While more expensive by acquisition cost, these newer agents are less toxic than the previously used drugs, and the triazoles offer the additional benefit of oral administration. The availability of new agents, future adoption of diagnostic tests for candidiasis, and susceptibility testing will have a major impact in the management of invasive candidiasis.     

Micafungin: the US perspective

Invasive fungal infections cause considerable morbidity and mortality in nosocomial settings and amongst immunocompromised hosts. Invasive candidiasis and aspergillosis remain the most common invasive fungal infections, with Candida spp. constituting the fourth most common bloodstream infection in the USA. Currently available antifungal therapies include the polyene, antimetabolite, allylamine, azole and echinocandin drug classes. Micafungin, approved in March 2005 by the Food and Drug Administration for use in the USA, has shown safety and efficacy for the treatment of candidiasis and aspergillosis in clinical trials in Japan, Europe and South Africa. Micafungin holds promise as a first-line treatment option for candidiasis, as well as prophylaxis against invasive fungal infections during periods of neutropenia in high-risk patients.     

Anticandidal activity of SPA-S-843, a new polyenic drug

The activity of a new, soluble and stable polyene (SPA-S-843) against Candida albicans was assessed by contact and culture tests and by inhibition of germ-tube formation. The drug demonstrated a higher contact activity and lower MICs than amphotericin B. This antimicrobial activity was more evident under acid pH and low ionic strength. In addition, the ability of SPA-S-843 to inhibit Candida sp. conversion from yeast to mycelial form was evident at low drug concentrations (0.25-0.62 mg/L).     

Host defence against disseminated Candida albicans infection and implications for antifungal immunotherapy

The different manifestations of Candida albicans infection are dictated by an underlying defect in the immune response of the host. Protective immunity to disseminated candidiasis, the manifestation of C. albicans infection discussed in this review, has traditionally been ascribed to innate immunity with emphasis on the role of granulocytes. Lately, however, immunological studies have learned that host defence against disseminated candidiasis is based on a complex interplay between innate and cell-mediated immunity. Despite the availability of new antifungal agents, mortality associated with disseminated C. albicans infection remains high. Immunotherapy that augments host defence is an important strategic option in the battle against disseminated candidiasis. Here, the authors review the chronological events in the pathogenesis of disseminated candidiasis that aid in predicting the impact of existing immunotherapy and the development of future immunomodulating strategies.