Neutrophils use a variety of cell-surface receptors for attachment to surfaces, such as the endothelium or opsonized pathogens. During inflammation or infection, chemoattractants or cytokines bind to neutrophils and upregulate or 'prime' their responsiveness. Priming can increase the number of some receptors expressed on the cell surface but can also change receptor function, so that the receptor has altered ligand-binding properties or becomes linked to new intracellular signalling systems.