KatieJane

yes, that's right, could the ligand block binding of the antibody?

My colleague and I are confused as to whether you can detect a receptor expressed on a cell surface to the same degree when it's bound by its ligand. For example, when dendritic cells secrete the cytokine IL-12, expression of its receptor is up-regulated. In trying to quantify this receptor expression by antibody detection/flow cytometry, we are worried that the binding of the IL-12 ligand may jeopardise the quantification of the receptor. Does it depend of the respective binding sites of the antibody and ligand? Does ligand binding always affect the capacity of the antibody to bind? Can anybody help?!