AlphaLISA SureFire Ultra Human and Mouse Phospho-STAT5 (Tyr694/699) Detection Kit, 10,000 Assay Points

Phospho-AlphaLISA SureFire Ultra assay principle

The Phospho-AlphaLISA SureFire Ultra assay measures a protein target when phosphorylated at a specific residue.

The assay uses two antibodies which recognize the phospho epitope and a distal epitope on the targeted protein. AlphaLISA assays require two bead types: Acceptor and Donor beads. Acceptor beads are coated with a proprietary CaptSure™ agent to specifically immobilize the assay specific antibody, labeled with a CaptSure tag. Donor beads are coated with streptavidin to capture one of the detection antibodies, which is biotinylated. In the presence of phosphorylated protein, the two antibodies bring the Donor and Acceptor beads in close proximity whereby the singlet oxygen transfers energy to excite the Acceptor bead, allowing the generation of a luminescent Alpha signal. The amount of light emission is directly proportional to the quantity of phosphoprotein present in the sample.

Phospho-AlphaLISA SureFire Ultra two-plate assay protocol

The two-plate protocol involves culturing and treating the cells in a 96-well plate before lysis, then transferring lysates into a 384-well OptiPlate™ plate before the addition of Phospho-AlphaLISA SureFire Ultra detection reagents. This protocol permits the cells viability and confluence to be monitored. In addition, lysates from a single well can be used to measure multiple targets.

Phospho-AlphaLISA SureFire Ultra one-plate assay protocol

Detection of Phosphorylated target protein with AlphaLISA SureFire Ultra reagents can be performed in a single plate used for culturing, treatment, and lysis. No washing steps are required. This HTS designed protocol allows for miniaturization while maintaining AlphaLISA SureFire Ultra quality.

Induction of STAT5 phosphorylation in PBMCs stimulated with various cytokines

PBMCs were isolated from healthy donors using Ficoll® Plaque Plus. Cells were seeded in a 96-well plate (400,000 cells/well) and starved for 2 hours in serum-free DMEM. Cells were then treated with the indicated cytokines for 15 minutes.

After treatment, the cells were lysed with 100 µL of Lysis Buffer for 10 minutes at RT with shaking (350 rpm). STAT5 Phospho (Tyr694/699) levels were evaluated using AlphaLISA SureFire Ultra. For the detection step, 10 µL of cell lysate (approximately 40,000 cells) were transferred into a 384-well white OptiPlate, followed by 5 µL of Acceptor mix and incubated for 1 hour at RT. Finally, 5 µL of Donor mix was then added to each well and incubated for 1 hour at RT in the dark. The plate was read on an Envision using standard AlphaLISA settings.

As expected, IL-4 and IL-6, as well as type I and II interferons induced STAT5 phosphorylation.

IFNα and IFNγ induce STAT5 phosphorylation in a dose-dependent manner

PBMCs were isolated from healthy donors and cultured for 6 days in complete DMEM containing 20 ng/mL M-CSF to differentiate them into macrophages. Macrophages were seeded in a 96-well plate (40,000 cells/well) in complete DMEM, and incubated overnight at 37°C, 5% CO2. Cells were starved for 2 hours and then treated with IFNα or IFNγ for 20 minutes.

After treatment, cells were lysed in 150 µL of Lysis Buffer for 10 minutes at RT with shaking (350 rpm). STAT5 Phospho (Tyr694/699) and Total levels were evaluated using respective AlphaLISA SureFire Ultra assays. For the detection step, 10 µL of cell lysate (approximately 2,600 cells) were transferred into a 384-well white OptiPlate, followed by 5 µL of Acceptor mix and incubated for 1 hour at RT. Finally, 5 µL of Donor mix was then added to each well and incubated for 1 hour at RT in the dark.

As expected, IFNα and IFNγ triggered a dose-dependent increase in the levels of Phospho STAT5 (Tyr694/699) while Total STAT5 levels remained unchanged.

THP-1 cells were seeded in a 96-well plate (100,000 cells/well) in complete medium containing 100 nM of PMA for 24 hours at 37°C, 5% CO2. The THP-1 derived macrophages were starved for 2 hours in HBSS + 0.1 % BSA and then treated with increasing concentrations of IFNα or IFNγ for 20 minutes.

After treatment, the cells were lysed with 60 µL of Lysis Buffer for 10 minutes at RT with shaking (350 rpm). STAT5 Phospho (Tyr694/699) and Total levels were evaluated using AlphaLISA SureFire Ultra. For the detection step, 10 µL of cell lysate (approximately 16,000 cells) were transferred into a 384-well white OptiPlate, followed by 5 µL of Acceptor mix and incubated for 1 hour at RT. Finally, 5 µL of Donor mix was then added to each well and incubated for 1 hour at RT in the dark. The plate was read on an Envision using standard AlphaLISA settings.

As expected, IFNα and IFNγ triggered a dose-dependent increase in the levels of Phospho STAT5 (Tyr694/699) while Total STAT5 levels remained unchanged.