Ligand binding nonspecific

Table I describes several of the fluorescent assays that have been used in our lab to study neutrophil activation. Fluorescein-labeled W-formylhexapeptide (FLPEP) has been used to characterize the ki- netics of ligand binding, dissociation, and internalization at 37°C (7,8). FLPEP is added to a suspension of cells, then receptor-bound and free FLPEP in solution are distinguished by adding antibody to fluorescein. This is a high-affinity antibody which binds free FLPEP within 1 s hut does not bind cell-bound FLPEP. When it binds the FLPEP, it quenches the fluorescein fluorescence. Hence the residual fluorescence after antibody addition represents FLPEP that is bound to the cell. Nonspecific binding is determined in cell suspensions that contain an excess of nonfluorescent peptide.

Fig. 10.7 ESI-FTICR mass spectra of three RNA targets at 2.5 pM each screened against 11 compounds at 25 pM each. The percent complexes and one-point values are shown for each ligand complex, (a) An example of a ligand that specifically binds target 2. (b) An example of a ligand that nonspecifically binds to all targets.

Piletsky SA, Terpetschnig E, Andersson HS, Nicholls lA, Wolfheis OS. Application of nonspecific fluorescent dyes for monitoring enantio-selective ligand binding to molecularly imprinted polymers. Fresenius J Anal Chem 1999 364 512-516. 

This increase is thought to be one of the early steps involved in so-called signal transduction and can result in the activation of enzyme systems responsible for subsequent metabolic or developmental changes. Lymphocytes show increases in intracellular calcium in response to many kinds of specific and nonspecific surface ligand binding, some of which lead to the cellular changes that we associate with an immune response. Many other classes of cells also show calcium changes in response to stimulation. 

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