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.
CXCR3 is a 7-TM GPCR that is selective for the CXC chemokines IP10, I-TAC and MIG [1]. Binding of IP-10 and MIG to CXCR3 induces Ca2+ mobilization, chemotaxis and inflammatory responses of T lymphocytes, and also act as potent inhibitors of angiogenesis. CXCR3 is highly expressed in IL-2-activated T lymphocytes in vitro [1], and in T lymphocytes present in inflamed tissues in rheumatoid arthritis and multiple sclerosis [2,3]. In vivo, neutralization of CXCR3 inhibits experimentally induced type I diabetes [4], peritonitis [5], and post-lung transplantation bronchiolitis obliterans syndrome [6].
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 [7]. Using this information, now the researcher can determine the number of receptors per cell on any given cell type.