Midiri Angelina, Mancuso Giuseppe, Lentini Germana, Famà Agata, Galbo Roberta, Zummo Sebastiana, Giardina Miriam, De Gaetano Giuseppe Valerio, Teti Giuseppe, Beninati Concetta, Biondo Carmelo
Department of Human Pathology, University of Messina, Messina, Italy.
Charybdis Vaccines Srl, Messina, Italy.
Med Mycol. 2020 Nov 10;58(8):1138-1148. doi: 10.1093/mmy/myaa012.
Members of the C. neoformans/C. gattiii species complex are an important cause of serious humans infections, including meningoencephalitis. We describe here a 45 kDa extracellular cellulase purified from culture supernatants of C. neoformans var. neoformans. The N-terminal sequence obtained from the purified protein was used to isolate a clone containing the full-length coding sequence from a C. neoformans var. neoformans (strain B-3501A) cDNA library. Bioinformatics analysis indicated that this gene is present, with variable homology, in all sequenced genomes of the C. neoformans/C. gattii species complex. The cDNA clone was used to produce a recombinant 45 kDa protein in E. coli that displayed the ability to convert carboxymethyl cellulose and was therefore designated as NG-Case (standing for Neoformans Gattii Cellulase). To explore its potential use as a vaccine candidate, the recombinant protein was used to immunize mice and was found capable of inducing T helper type 1 responses and delayed-type hypersensitivity reactions, but not immune protection against a highly virulent C. neoformans var grubii strain. These data may be useful to better understand the mechanisms underlying the ability C. neoformans/C. gattii to colonize plant habitats and to interact with the human host during infection.
