To assess the role of ASP5 in cyst wall formation, we used the fluorescent Dolichos biflorus Agglutinin (DBA) lectin to detect the glycosylated protein CST1 (one of the few available markers of the T. gondii cyst wall) [37], following pH induced differentiation of PRUΔku80Δasp5 strain parasites in vitro. This evidence concerns the gene CST1 and cyst.