Arginine level by ELISA as a surrogate for Arginase activity
Arginine metabolism is involved in many cell functions and plays an important role among others in the regulation of immune cell reactivity and carcinogenesis. For instance, while Arginine is essential for T cell activity, TAMs and MDSCs – through the expression and activity of Arginase – favor its degradation thereby participating in immunosuppression.
Novel therapeutic options in immuno-oncology consist in manipulating such a metabolic pathway to relieve the function of immunosuppressive macrophages. For instance, Arginase 1 can be targeted directly through the use of Arginase inhibitors (eg. INCB-001158) or indirectly through the modulation of specific signaling pathways (eg. PI3K). Finally, whatever the mechanism of action of drug candidates, Arginine remains a suitable surrogate biomarker of Arginase activity and its quantification can now be approached by ELISA!
PI3K signaling pathway inhibition limits Arginase 1 activity of M2 polarized macrophages. During their polarization, M2 macrophages were treated with increasing concentrations of LY294002, a reference PI3K inhibitor. ELISA-based quantification of L-Arginine increase in the supernatants (using IS-I-0400 kit) highlighted a dose-dependent inhibition of Arginine catabolism.
To allow the determination of neurotransmitter content and localization, we have set up and validated a series of antibodies targeting key neurotransmitters. Besides antibodies, and for appropriate biological sample preparation, we developed an immunostaining kit for immunofluorescence staining of varied types of biological materials.