Trypanosoma cruzi surface mucins with exposed variant epitopes

Area of Science:

• Parasitology
• Molecular Biology
• Glycobiology

Background:

• Trypanosoma cruzi, the causative agent of Chagas disease, possesses surface mucins crucial for host infection and survival.
• These mucins are key acceptors of sialic acid, a vital monosaccharide for parasite infectivity.
• A large mucin-like gene family, TcMUC (approx. 500 members), exists in T. cruzi, divided into subfamilies based on tandem repeats.

Purpose of the Study:

• To investigate the glycosylation and expression of T. cruzi mucins from different subfamilies.
• To determine if TcMUC gene products are O-glycosylated in vivo and exposed on the parasite surface.
• To assess the immunogenicity of TcMUC mucins during infection.

Main Methods:

• Transfection of T. cruzi parasites with tagged TcMUC gene members from distinct subfamilies.
• Analysis of O-glycosylation patterns using biochemical methods.
• Immunological detection of recombinant mucin products and N-terminal peptides using sera from infected hosts.

Main Results:

• Only the TcMUC gene product with tandem repeats exhibited significant O-glycosylation in vivo.
• The identified O-linked oligosaccharides matched those found in endogenous mucins.
• Recombinant mucins and peptides from the hypervariable N-terminal region were recognized by sera from infected mice, indicating in vivo expression and immunogenicity.

Conclusions:

• TcMUC genes with repeats encode highly O-glycosylated mucins essential for T. cruzi surface expression.
• These mucins, including their variable N-terminal regions, are recognized by the host immune system during Chagas disease.
• The findings provide insights into parasite-host interactions and potential targets for diagnostics or therapeutics.