title: Paracoccidioides lutzii Plp43 is an active glucanase with partial antigenic identity with P. brasiliensis gp43.
abstract: BACKGROUND
  Paracoccidioides brasiliensis and P. lutzii cause paracoccidioidomycosis (PCM). P. brasiliensis main diagnostic antigen is glycoprotein gp43, and its peptide sequence is 81% identical with a P. lutzii ortholog here called Plp43. P. lutzii ("Pb01-like") apparently predominates in Midwestern/Northern Brazil, where high percentages of false-negative reactions using P. brasiliensis antigens have recently been reported. The aim of this work was to produce recombinant Plp43 to study its antigenic identity with gp43.
  
  
  METHODS
  We expressed rPlp43 as a secreted major component in Pichia pastoris and studied its reactivity in immunoblot with PCM patients' sera from Southwestern and Midwestern Brazil.
  
  
  RESULTS
  We showed that rPlp43 is not glycosylated and bears glucanase activity. The protein did not react with anti-gp43 monoclonal antibodies in immunoblot, suggesting absence of the corresponding gp43 epitopes. Nevertheless, common epitope(s) might exist, considering that gp43-positive PCM sera recognized rPlp43 in immunoblot, while gp43-negative sera (33 out of 51) from patients resident in Midwestern Brazil were also rPlp43-negative. Two genotyped P. lutzii were from patients with gp43-negative sera, suggesting that non-reactive sera are from patients infected with this species.
  
  
  CONCLUSIONS
  Our data suggest that gp43 and Plp43 bear one or only a few common epitopes and that gp43 cannot be used in diagnosis of PCM patients infected with P. lutzii probably because Plp43 is poorly expressed during infection.
authors.affiliation: Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina-Universidade Federal de São Paulo (EPM-UNIFESP), São Paulo, Brazil.
authors.forename: Natanael P
authors.initials: NP
authors.lastname: Leitão
authors.affiliation: Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina-Universidade Federal de São Paulo (EPM-UNIFESP), São Paulo, Brazil.
authors.forename: Milene C
authors.initials: MC
authors.lastname: Vallejo
authors.affiliation: Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina-Universidade Federal de São Paulo (EPM-UNIFESP), São Paulo, Brazil.
authors.forename: Palloma M
authors.initials: PM
authors.lastname: Conceição
authors.affiliation: Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina-Universidade Federal de São Paulo (EPM-UNIFESP), São Paulo, Brazil.
authors.forename: Zoilo P
authors.initials: ZP
authors.lastname: Camargo
authors.affiliation: Núcleo de Doenças Infecciosas e Tropicais de Mato Grosso, Universidade Federal de Mato Grosso, Mato Grosso, Brazil.
authors.forename: Rosane
authors.initials: R
authors.lastname: Hahn
authors.affiliation: Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina-Universidade Federal de São Paulo (EPM-UNIFESP), São Paulo, Brazil.
authors.forename: Rosana
authors.initials: R
authors.lastname: Puccia
mesh_terms: D000595:Amino Acid Sequence; D000946:Antigens, Fungal / Q000737:chemistry / Q000276:immunology / Q000378:metabolism; D000939:Epitopes; D005656:Fungal Proteins / Q000737:chemistry / Q000276:immunology / Q000378:metabolism; D006023:Glycoproteins / Q000737:chemistry / Q000276:immunology / Q000378:metabolism; D006026:Glycoside Hydrolases / Q000737:chemistry / Q000276:immunology / Q000378:metabolism; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010228:Paracoccidioides / Q000737:chemistry / Q000145:classification / Q000201:enzymology / Q000276:immunology; D010229:Paracoccidioidomycosis / Q000276:immunology / Q000382:microbiology
chemical_list: C103180:43 kDa protein, Paracoccidioides; D000946:Antigens, Fungal; D000939:Epitopes; D005656:Fungal Proteins; D006023:Glycoproteins; D006026:Glycoside Hydrolases