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

Zheng-xin He,Yan Cheng,Li-na Zhang,Wei Li,Tian-wen Hou,Jing Chen,Hai-pu Zhang

doi:10.3389/fmicb.2015.00920

Zheng-xin He, Yan Cheng + Show 5 more

Open Access

https://doi.org/10.3389/fmicb.2015.00920

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Abstract

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.

Highlights

Invasive candidiasis (IC) continues to be a life-threatening infectious disease affecting an everincreasing number of hospitalized patients and, of particular concern, causing considerably high morbidity and mortality
Establishment of the Murine Model of Systemic Candidiasis Within 6 h after C. albicans SC5314 administration, the mice show typical symptoms of infection including sweat, physical inactivity compared with the control mice
The kidneys of C. albicans-infected mice contained filamentous fungal cells which were associated with leukocyte infiltrates (Figure 2A), but there was no evidence of fungal cells or immune cell infiltrates (Figure 2B) in the kidneys from the control mice

Summary

Introduction

Invasive candidiasis (IC) continues to be a life-threatening infectious disease affecting an everincreasing number of hospitalized patients and, of particular concern, causing considerably high morbidity and mortality. In the USA, Candida species is among the five major pathogens leading to nosocomial blood stream infections (BSIs) and causing 8–10% of nosocomial BSIs (Pappas, 2006; Pfaller and Diekema, 2007; Morrissey, 2013; Sievert et al, 2013). Though a variety of Candida species can produce invasive infection, Candida albicans (C. albicans) continues to be identified as a leading pathogen. The low sensitivity (approximately 50%) and positive results may appear only in the advanced stage of infection which dramatically hampers its role in clinical practice (Yera et al, 2001). Though the germ tube test has been performed successfully on samples collected directly from positive blood cultures, rather than waiting for Candida colonies to grow on agar plates (Terlecka et al, 2007; Sheppard et al, 2008), the long duration is still an overwhelming disadvantage of blood culture

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