Format

Send to

Choose Destination
Parasitology. 2004 Apr;128(Pt 4):391-6.

Toxoplasma gondii major surface antigen (SAG1): in vitro analysis of host cell binding.

Author information

1
School of Biochemistry and Molecular Biology, University of Leeds, Leeds LS2 9JT, UK.

Abstract

Previous studies have indicated that SAG1, the major surface molecule of the protozoan parasite Toxoplasma gondii, is an important attachment ligand for the host cell. However, the research data that supports this claim comes largely from studies investigating tachyzoite binding, and not SAG1 binding per se. In this study we successfully developed an in vitro attachment assay to directly evaluate the mechanism of SAG1-host cell binding. Competition experiments were then performed using SAG1 that had been pre-treated with the neoglycoprotein BSA-glucosamide or with antibody. Soluble BSA-glucosamide blocked SAG1 attachment to MDBK cells in a dose-dependent manner, implying that SAGI binding is mediated, in part, via attachment to host cell surface glucosamine. Interestingly, pre-incubation of SAG1 in polyclonal sera from chronically infected mice failed to block binding. This challenges the assumption that anti-SAG1 antibodies block parasite attachment through the masking of SAG1 host cell binding domains. Taken together, this evidence presents new strategies for understanding SAG1-mediated attachment.

PMID:
15151144
DOI:
10.1017/s0031182003004736
[Indexed for MEDLINE]
Free full text

Supplemental Content

Full text links

Icon for White Rose Research Online
Loading ...
Support Center