Src Inhibitor 3 is a potent, orally active c-terminal Src kinase (CSK) with IC50 values below 3 nM and 4 nM in CSK HTRF and Caliper assay, respectively. Src Inhibitor 3 shows the ability to increase T cell proliferation induced by T cell receptor signaling.IC50 & Target: IC50: <3 nM (c-terminal Src kinase in CSK HTRF assay), 4 nM (c-terminal Src kinase in Caliper assay)In Vivo: Src Inhibitor 3 reduces inhibitory LCK phosphorylation in vivo upon oral dosing and shows the ability to enhance T cell activation in response to antigen stimulation.