Scavenger receptors on human monocytes have been found to bind to β-glucan,20 and MARCO (on CpG-ODN-pretreated macrophages) has been found to participate in the uptake of zymosan (which is derived from β-glucan);21 therefore β-glucan was used in this study to address the question of whether it might be a ligand for MARCO and to explore possible interaction between MARCO, tuberculosis and β-glucan. This evidence concerns the gene PPIB and tuberculosis.