Characterization of monoclonal antibody MEST-2 specific to glucosylceramide of fungi and plants

An IgG2a monoclonal antibody anti-glucosylceramide was established and term ed MEST-2. High performance thin layer chromatography immunostaining, and s olid-phase radioimmunoassay showed that MEST-2 reacts with glucosylceramide from yeast and mycelium forms of Paracoccidioides brasiliensis, Histoplasm a capsulatum, and Sporothrix schenckii; from hyphae of Aspergillus fumigatu s; and from yeast forms of Candida albicans, Cryptococcus neoformans, Crypt ococcus laurentii, and Cryptococcus albidus, Studies on the fine specificit y of MEST-2 showed that it recognizes the beta -D-glucose residue, and that the 2-hydroxy group present in the fatty acid is an important auxiliary fe ature for the antibody binding. It was also demonstrated that phosphatidylc holine and ergosterol modulate MEST-2 reactivity to glucosylceramide, by so lid-phase radioimmunoassay. Indirect immunofluorescence showed that MEST-2 reacts with the surface of yeast forms of P. brasiliensis, H. capsulatum an d S. schenckii. Weak staining of mycelial forms of P, brasiliensis and hyph ae of A. fumigatus was also observed. The availability of a monoclonal anti body specific to fungal glucosylceramide, and its potential use in analyzin g biological roles attributed to glucosylceramide in fungi are discussed.