RESUMO
Schistosoma mansoni enzymes play important roles in host-parasite interactions and are potential targets for immunological and/or pharmacological attack. The aim of this study was to comparatively assess the presence of hydrolytic activities (phosphatases, glycosidases, aminopeptidases) in soluble (SF) and membrane (MF) fractions from different S. mansoni developmental stages (schistosomula 0 and 3h, juveniles, and adult worms of 28 and 45days-old, respectively), by using simple enzyme-substrate microassays. Our results show and confirm the prominent presence of alkaline phosphatase (AlP) activity in the MF of all the above parasite stages, highlighting also the relevant presence of MF-associated α-mannosidase (α-MAN) activity in juveniles. A soluble AlP activity, together with ß-N-D-acetylglucosaminidase (ß-NAG), and α-MAN activities, was detected in SF of schistosomulum 0h. Soluble ß-NAG, α-MAN, acid phosphatase (AcP), leucin (LAP) and alanine (AAP) aminopeptidase activities were also seen in the SF of the other different developmental stages. This work shows different soluble and membrane-associated hydrolytic capacities in each S. mansoni developmental stage from schistosomula to adults that might be exploitable as potential new targets for immune and/or chemoprophylactic strategies.
Assuntos
Fosfatase Alcalina/metabolismo , Glicosídeo Hidrolases/metabolismo , Proteínas de Helminto/metabolismo , Schistosoma mansoni/enzimologia , Schistosoma mansoni/crescimento & desenvolvimento , alfa-Manosidase/isolamento & purificação , alfa-Manosidase/metabolismo , Fosfatase Alcalina/imunologia , Fosfatase Alcalina/isolamento & purificação , Aminopeptidases/química , Aminopeptidases/imunologia , Aminopeptidases/isolamento & purificação , Animais , Membrana Celular/química , Membrana Celular/enzimologia , Glicosídeo Hidrolases/imunologia , Glicosídeo Hidrolases/isolamento & purificação , Proteínas de Helminto/imunologia , Estágios do Ciclo de Vida , Schistosoma mansoni/imunologia , Esquistossomose mansoni/terapia , alfa-Manosidase/imunologiaRESUMO
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.