Description
Interferon Regulatory Factor 4 (IRF4) is a transcription factor essential for lymphocyte development, activation, and differentiation in B cells, T cells, and dendritic cells. IRF4 functions as both a transcriptional activator and repressor, forming complexes with PU.1, BATF, and other transcription factors. In B cells, IRF4 is critical for germinal center formation and plasma cell differentiation, while in T cells it controls Th2, Th17, and follicular helper T cell differentiation. Dysregulated IRF4 expression is a hallmark of multiple myeloma and certain lymphomas, where it promotes plasma cell survival. IRF4 is an attractive therapeutic target for hematologic malignancies and autoimmune diseases.
The AlphaLISA SureFire Ultra Human Total IRF4 is a sandwich immunoassay for the quantitative detection of total IRF4 in cellular lysates, using Alpha Technology.
Formats:
The HV (high volume) kit contains reagents to run 100 wells in 96-well format, using a 60 μL reaction volume.
The 500-point kit contains enough reagents to run 500 wells in 384-well format, using a 20 μL reaction volume.
The 10,000-point kit contains enough reagents to run 10,000 wells in 384-well format, using a 20 μL reaction volume.
The 50,000-point kit contains enough reagents to run 50,000 wells in 384-well format, using a 20 μL reaction volume.
AlphaLISA SureFire Ultra kits are compatible with:
Cell and tissue lysates
Antibody modulators
Biotherapeutic antibodies
AlphaLISA SureFire Ultra kits can be used for:
Cellular kinase assays
Receptor activation studies
High-throughput screening for preclinical studies
Total-AlphaLISA SureFire Ultra assay principle
The Total-AlphaLISA SureFire Ultra assay measures the expression level of a target protein in a biological sample (e.g. cell lysate).
The Total-AlphaLISA SureFire Ultra assay uses two antibodies which recognize two different distal epitopes on the target 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 target 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 for the generation of a luminescent Alpha signal. The amount of light emission is directly proportional to the quantity of protein present in the sample.
Total-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 Total-AlphaLISA SureFire Ultra detection reagents. This protocol enables cell 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 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.
Differential IRF4 expression in various cell lines
Adherent cells were grown to confluency in a T175 flask at 37°C, 5% CO2 and were lysed with Lysis Buffer at a density of 0.5 x 106 cells/mL. Suspension cells were harvested, washed in HBSS and lysed with Lysis Buffer at 1.6 x 106 cells/mL.
IRF4 Total levels were evaluated using the AlphaLISA SureFire Ultra assay. For the detection step, 10 µL of cell lysate 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, Total IRF4 protein is highly expressed in B lymphoma cell lines like RPMI 8226 and Karpas299, with no expression detected in Jurkat or A431.
Assay sensitivity - cell lysate
Cell lysate was prepared from Karpas 299 cells. Cells were harvested, washed with HBSS and lysed at a density of 0.25 x 106 cells/mL in Lysis Buffer.
Lysates were serially diluted in Lysis Buffer and assayed for Total IRF4 levels using the AlphaLISA SureFire Ultra kit. For the detection step, 10 µL of lysate was transferred into a 384-well white OptiPlate, followed by 5 µL of Acceptor mix and incubated for 1 hour at room temperature. 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.
Approximate number of cells/datapoint is indicated on the graph. The assay can detect Total IRF4 down to 200 cells.
