Development of an immunomagnetic bead assay for quantitative detection enolase of Candida albicans / 医学研究生学报

ABSTRACT

Objective To develop an immunomagnetic bead ( IMB) assay for quantitative detection enolase ( Eno) of Candi-da albicans, and to improve the diagonosis of invasive candidiasis . Methods The immunomagnetic bead was prepared by conjuga-ting with Anti Eno of Candida albicans monoclonal antibody .HRP-conjugated goat polyclonal antibody against Candida albicans Eno was employed as detecting antibody .The performance parameters of the IMB assay including precision , specificity, linear range and limit of detection were verified by using recombinant Candida albicans Eno.Then the developed assay was applied to determine Eno levels in supernatant of pathogenic fungi cultures . Results The intra and inter-coefficient of variation was 4.54%, 5.87% and 5.26%, 8.82%at the concentration of 25 ng/mL and 5 ng/mL, respectively.The limit of detection was 0.5 ng/mL.The linear range was(0.5-50) ng/mL.The level of Eno in Candida albicans culture after incubated in 37℃for 24 h was 3.89 ng/mL and gradually in-creased to 37.89 ng/mL at 120 h.There was a positive correlation between the level of Eno and growth hyphae of Candiad albicans. There was weak cross reaction with Candida parapsilosis and no cross reaction with Candida tropicalis, Candida guilliermondii, Candida glabrata, Cryptococcus neoformans and Saccharomyces cerevisiae. Conclusion An IMB assay for quantitative detection Eno of Candida albicans was developed , which was more sensitive , rapid and reliable than previous qualitative ELISA .The IMB assay has the potential to be applied to the research in invasive candidasis .