The FlowCellect™ GPCR identification kits are designed for flow cytometry applications, which can be used for the identification and quantification of the surface expression level of GPCRs on any cells. The kit uses a GPCR antibody validated for flow cytometry to detect receptor expression, and also includes both positive and negative control cells with well characterized receptor expression levels for the purpose of quantification.
Chemokine receptors are very attractive targets because they are highly expressed on immune cells and regulate leukocyte activation and trafficking. Many of these targets have been indicated to play a key role in certain diseases states such as HIV infection, Rheumatoid Arthritis, and Diabetes. The expression levels of these receptors often reflect the different states of infectious diseases and inflammation.
Chemokine receptors are seven transmembrane G-Protein coupled receptors (GPCRs). The chemokine receptor family comprises of eighteen GPCR targets, in which ten are CC chemokine receptors, seven are CXC chemokine receptors, and one is a CX3C chemokine receptor. Currently, Millipore has launched 12 GPCR surface identification kits with an initial focus on the chemokine receptor family.
CXCR1 (also known as IL-8RA) is a Gi/o-coupled GPCR expressed on neutrophils, CD8 (+) T cells, and intestinal epithelial cells [5,6,7]. CXCR1 binds with high affinity to the chemokine interleukin-8 (IL-8) and much lower affinity to GRO, whereas a related receptor, CXCR2, binds with equal affinity to IL-8 and GRO [3]. CXCR1 has been proposed to be the primary regulator of neutrophil response to IL-8 in sepsis [2]. Antagonists of CXCR1 and CXCR2 have been developed and display efficacy in animal models of reperfusion injury [1,4].
The control cells provided in the kit are based on the commercially available ChemiScreen™ GPCR stable cell lines from Millipore. Both the positive and negative control cell lines have been fully characterized using Pharmacology techniques such as radioligand binding assay to determine the receptor number for each cell type [8]. Using this information, now the researcher can determine the number of receptors per cell on any given cell type.