Variant cysteine-rich surface proteins of Giardia isolates from human and animal sources.
AUTOR(ES)
Bruderer, T
RESUMO
Cloned Giardia isolates obtained from a sheep, a calf, and a human possessed a major membrane protein that showed marked intraspecific variations in size as demonstrated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis following surface biotinylation and radioiodination. Metabolic labeling with [35S] cysteine and electrophoretic analysis also revealed for each cloned isolate a predominant protein that corresponded in size to the major surface protein demonstrated by surface labeling techniques. Immunoprecipitation studies with a polyclonal antiserum specifically directed against the 90-kDa major cysteine-rich protein purified from a subclone of the sheep isolate (O2-4A1) showed that the cysteine-rich protein and the major surface protein are identical. The surface location of the antigen was further corroborated by the reaction of fluorescence-labeled antibodies raised against the 90-kDa O2-4A1 cysteine-rich protein with the entire surface of live trophozoites of the homologous clone. The ability of the cloned Giardia isolates to undergo variations of their cysteine-rich surface protein (CRISP) was demonstrated by the spontaneous appearance of new CRISPs in clonally derived populations during prolonged in vitro culturing and in cultures of the O2-4A1 clone that had survived treatment with the cytotoxic anti-90-kDa CRISP antiserum specific for the surface antigen of this clone. The surviving progeny were devoid of the original CRISP, as judged by resistance to the immune serum. Subsequent cysteine metabolic labeling of the recloned surviving trophozoites demonstrated a large number of new variants, each expressing a single CRISP that varied significantly in molecular weight from those in the different cloned lines. These studies suggest that the presence of CRISPs and their variations are not restricted to Giardia isolates obtained from humans but are universal phenomena among the Giardia duodenalis types of organisms.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=280942Documentos Relacionados
- The cysteine-rich protein gene family of Giardia lamblia: loss of the CRP170 gene in an antigenic variant.
- Small cysteine-rich antifungal proteins from radish: their role in host defense.
- Epithelins 1 and 2: isolation and characterization of two cysteine-rich growth-modulating proteins.
- Localization of human platelet autoantigens to the cysteine-rich region of glycoprotein IIIa.
- Sequence analysis and lipid modification of the cysteine-rich envelope proteins of Chlamydia psittaci 6BC.