Nature ofCandida albicans-derived carbohydrate antigen recognized by a monoclonal antibody in patient sera and distribution overCandidaspecies

Abstract

The minimal epitope of an anti-Candida albicans mannan monoclonal antibody (MAb) EB-CA1, used to detect mannanemia in patient sera, was determined, MAb EB-CA1 exhibited reactivity with oligomannosides released from the mannan acid stable domain, converted into neoglycolipids (NGLs) and coated onto ELISA plates. Reactivity occurred with mannopentaose and higher oligomers, whereas mannotriose and mannotetraose were unreactive. MAb EB-CA1 binding to mannan acid stable mannopentaose NGL displayed a dose dependent and saturable specific reactivity curve whereas there was a complete absence of binding, even at high concentrations, with NGLs constructed from the beta-1,2-linked mannopentaose derived from the mannan acid labile fraction. MAb EB-CA1 binding to acid stable mannopentaose NGL was inhibited by the homologous oligomannoside but not by mannotriose and mannotetraose. NMR analysis showed that mannotriose and mannotetraose contained exclusively alpha-1,2-linked D-mannopyranose units and that mannopentaose was a mixture of a mannopentaose alpha-1,2-linked and an isomer in which the fifth mannose was alpha-1,6-linked to the reducing unit of manno-alpha-1,2 tetraose. Western blot analysis has shown that MAb EB-CA1 epitope was expressed on a wide range of C. albicans manno-glycoconjugate as well as on manno-glycoconjugates of other pathogenic species of the genus Candida, viz. C. tropicalis, C. glabrata, C. parapsilosis and C. krusei.

The use of mannan antigen and anti-mannan antibodies in the diagnosis of invasive candidiasis: recommendations from the Third European Conference on Infections in Leukemia

“…[29], where the sensitivity for C. albicans was 78% compared to 15% and 0 for C. parapsilosis and C. krusei , respectively. Even though the sensitivity varied among the studies, it was clearly lower in cases of C. parapsilosis and C. krusei , probably because of the lower amount of Mn produced and released by these species [19,30]. …”

“…The observation of this balance between Mn epitope circulation and A-Mn antibody response in patients' serum has led to the idea that the combined detection of mannanemia and A-Mn antibodies by enzyme-linked immunosorbent assays (ELISAs) may be a useful diagnostic procedure [17,18]. Therefore, ELISAs have been developed for the detection of Mn, a major Candida cell wall constituent, and A-Mn and are marketed as Platelia™ Candida Antigen (Bio-Rad Laboratories, Marnes-la-Coquette, France) and Platelia™ Candida Antibody [16,19]. Nowadays, ELISA is the assay most frequently used in Europe and consequently is the one with the most scientific data published.…”

Effect of monosaccharide composition, glycosidic linkage position and anomericity on the electrophoretic mobility of labeled oligosaccharides

“…Thus, these microbial surface oligosaccharides are of clinical interest because of the roles they play in infectious diseases. As targets of diagnostic assays, they can help differentiate species and strains [1,[6][7][8]. Therapeutically, cell surface glycans have been shown to elicit antibody responses that protect against subsequent bacterial and fungal infections [1,[9][10][11].…”

The Cek1‑mediated MAP kinase pathway regulates exposure of α‑1,2 and β‑1,2‑mannosides in the cell wall ofCandida albicansmodulating immune recognition

“…53,54 We made use of flow cytometry analysis and specific antibodies to determine the levels of a-1,2 and b-1,2 linked mannosides (a-M and b-M) at the surface of cek1 mutants under standard conditions (YEPD, 37 C). The absence of Cek1 led to an almost 4-fold increase on the levels of a-M in cells at stationary phase when compared to the wild type strain, as inferred using the EB-CA1 specific monoclonal antibody (MAb) 55 : 2600 § 183.95 versus 665.8 § 124.25 ( Fig. 2A).…”