Paracoccidioides lutzii Plp43 Is an Active Glucanase with Partial Antigenic Identity with P. brasiliensis gp43

Author(s)

Leitao, Jr., Natanael P. ^[1] ; Vallejo, Milene C. ^[1] ; Conceicao, Palloma M. ^[1] ; Camargo, Zoilo P. ^[1] ; Hahn, Rosane ^[2] ; Puccia, Rosana ^[1]

Affiliation

^[1] Univ Fed Sao Paulo EPM UNIFESP, Escola Paulista Med, Dept Microbiol Imunol & Parasitol, Sao Paulo - Brazil

^[2] Univ Fed Mato Grosso, Nucleo Doencas Infecciosas & Tropicais Mato Gross, Mato Grosso - Brazil

• Document type: Journal article
• Source: PLoS Neglected Tropical Diseases; v. 8, n. 8 AUG 2014.
• Web of Science Citations: 11

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. Methodology: 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. Principal Findings: 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. Conclusion: 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. (AU)

• FAPESP's process: 06/05095-6 - Analysis of exported vesicular structures and of secreted molecules by the pathogenic fungi Paracoccidioides brasiliensis e Cryptococcus neoformans
• Grantee: Rosana Puccia
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 10/03193-6 - Heterolougous expression and antigenic characterization of Plgp43 from Paracoccidioides lutzii
• Grantee: Natanael Pinheiro Leitão Júnior
• Support Opportunities: Scholarships in Brazil - Master