Characterisation of alpha-1 giardin: an immunodominant Giardia lamblia annexin with glycosaminoglycan-binding activity.
Int J Parasitol
; 33(12): 1341-51, 2003 Oct.
Article
em En
| MEDLINE
| ID: mdl-14527517
ABSTRACT
Alpha-1 giardin is an immunodominant protein in the intestinal protozoan parasite Giardia lamblia. The Triage((R)) parasite panel, used to detect copro-antigens in stool from giardiasis patients, reacts with an epitope between amino acids 160 and 200 in alpha-1 giardin. This region of the protein is also highly immunogenic during human infections. Alpha-1 giardin is related to annexins and like many other annexins it was shown to be plasma membrane associated. Immunoelectron and immunofluorescence microscopy revealed that some alpha-1 giardin are displayed on the surface of recently excysted cells. Recombinant alpha-1 giardin displayed a Ca(2+)-dependent binding to glycosaminoglycans (GAGs), in particular heparan sulphate, a common GAG in the intestinal tract. Recombinant alpha-1 giardin bound to thin sections of human small intestine, a binding which could be inhibited by adding increasing concentrations of sulphated sugars. A surface associated trypsin activated Giardia lectin (taglin) has been suggested to be important for G. lamblia attachment. In this study we show that a monoclonal antibody that inhibits taglin recognises alpha-1 and alpha-2 giardin. Thus, alpha-1 giardin is a highly immunoreactive GAG-binding protein, which may play a key role in the parasite-host interaction. Our results further show a conserved function of annexins from lower to higher eukaryotes.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Giardíase
/
Giardia lamblia
/
Oocistos
/
Antígenos de Protozoários
Limite:
Animals
/
Humans
Idioma:
En
Ano de publicação:
2003
Tipo de documento:
Article