AlphaLISA SureFire Biotin-Free Human and Mouse Total IRF5 Detection Kit, 50,000 assay points

Total-AlphaLISA SureFire Ultra Biotin Free 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 Total-AlphaLISA SureFire Ultra Biotin Free 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.

Total-AlphaLISA SureFire Ultra one-plate assay protocol

Detection of Total target protein with AlphaLISA SureFire Ultra Biotin Free 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 robust AlphaLISA SureFire Ultra quality.

RPMI 8226 cells were seeded in a 96-well plate (200,000 cells/well) in complete medium and incubated for approximately 10 minutes at 37°C, 5% CO2. The cells were treated with increasing concentrations of CpG-B ODN 2006 or ODN 1668 (MedChem Express, HY-150218, HY-150726 respectively) for 3 hours.

After treatment, the cells were spun down at 1200 rpm for 5 minutes, supernatant was removed and cells were lysed with 50 µL of Lysis Buffer for 10 minutes at RT with shaking (350 rpm). Aggregate, Phospho (Ser446) and Total IRF5 levels were evaluated using respective AlphaLISA SureFire Biotin Free assays. 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, CpG-B triggered a dose-dependent increase in Aggregate and Phospho (Ser446) IRF5 while Total levels remained unchanged.

Daudi cells were seeded in a 96-well plate (400,000 cells/well) in complete medium and incubated for approximately 10 minutes at 37°C, 5% CO2. The cells were treated with increasing concentrations of CpG-B ODN 2006 (MedChem Express, HY-150218) for 3 hours.

After treatment, the cells were spun down at 1200 rpm for 5 minutes, supernatant was removed and cells were lysed with 50 µL of Lysis Buffer for 10 minutes at RT with shaking (350 rpm). Phospho (Ser446) and Total IRF5 levels were evaluated using respective AlphaLISA SureFire Biotin Free assays. For the detection step, 10 µL of cell lysate (approximately 80,000 cells) was 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, CpG-B triggered a dose-dependent increase in Phospho (Ser446) IRF5 while Total levels remained unchanged.

Validation of Phospho (Ser446)/Total IRF5 in R848 treated cells

RPMI 8226 cells were seeded in a 96-well plate (400,000 cells/well) in complete medium and incubated for approximately 10 minutes at 37°C, 5% CO2. The cells were treated with increasing concentrations of R848 (InvivoGen) for 4 hours.

After treatment, the cells were spun down at 1200 rpm for 5 minutes, supernatant was removed and cells were lysed with 50 µL of Lysis Buffer for 10 minutes at RT with shaking (350 rpm). Phospho (Ser446) and Total IRF5 levels were evaluated using respective AlphaLISA SureFire Biotin Free assays. For the detection step, 10 µL of cell lysate (approximately 80,000 cells) was 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.

Treatment with a TLR7/8 agonist, R848, induced a dose-dependent increase in the levels of Phospho IRF5 while Total levels remained unchanged.

Validation of Aggregate/Phospho (Ser446)/Total IRF5 in Calyculin A treated cells

THP-1 cells were seeded in a 96-well plate (200,000 cells/well) in complete medium and incubated for approximately 10 minutes at 37°C, 5% CO2. The cells were treated with increasing concentrations of Calyculin A for 3 hours.

After treatment, the cells were spun down at 1200 rpm for 5 minutes, supernatant was removed, and cells were lysed with 50 µL of Lysis Buffer for 10 minutes at RT with shaking (350 rpm). Aggregate, Phospho (Ser446) and Total IRF5 levels were evaluated using respective AlphaLISA SureFire Biotin Free assays. 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.

Treatment with Calyculin A triggered a dose-dependent increase in the levels of Phospho (Ser446) and Aggregate IRF5 while Total levels remained unchanged.

Selectivity of Total IRF5 assay

Total IRF5 protein levels were assessed in A549 wild type (WT) and A549 IRF5 knockout (KO) (Abcam ab301006) cells cultured to confluency in T75 flasks at 37°C, 5% CO₂.

Each flask was lysed in 2 mL of Lysis Buffer for 10 minutes at RT with shaking (350 rpm). Lysates were then evaluated for Total IRF5 using the AlphaLISA SureFire Biotin Free assay kit.

For the detection step, 10 µL (approximately 10,000 cells) of cell lysate was transferred into a 384-well white OptiPlate, followed by 5 µL Acceptor Mix and incubated for 1 hour at RT. Finally, 5 µL of Donor Mix was 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, Total IRF5 protein was detected in WT cells, with very low signal detected in the IRF5 KO cell, demonstrating assay selectivity.

Expression of IRF5 in various cell lines

Adherent cell lines were seeded in a 96-well plate (40,000 cells/well) and incubated overnight at 37°C, 5% CO2. Cells were lysed with 200 µL of Lysis Buffer for 10 minutes at RT with shaking (350 rpm).

Suspension cell lines were seeded in a 96-well plate (400,000 cells/well) and lysed with 200 µL of Lysis Buffer for 10 minutes at RT with shaking (350 rpm).

IRF5 levels were evaluated using the AlphaLISA SureFire Biotin Free assay. For the detection step, 10 µL (approximately 2,000 adherent cells and 20,000 suspension cells) of cell lysate was 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.

Expression of IRF5 is varied among human and mouse cell lines. High levels of expression was detected in THP-1, RPMI 8226 and RAW 264.7.