CX3CL1 and infection: Other genes and pathways less expressed in APEC O2-GFP infected heterophils included the granulocyte adhesion and diapedesis pathway, and particularly CCL19, CX3CL1, CXCL8, and VCAM1 expression, with important roles in attracting heterophils to the site of infection and promoting adhesin to endothelial cells.