CST thoroughly validates each antibody available in the SignalStar Multiplex IHC Panel Builder menu. Various combinations of antibodies are tested through titration and fluorophore pairing, and in both rounds of imaging. Testing is performed on a variety of tumors and tissue types. We also rigorously test the parent antibodies used in the traditional chromogenic assay, as they serve as the foundation of this fluorescent assay.
SignalStar Multiplex IHC Kits & Reagents haven’t yet been validated for use in frozen tissues. We’re in the process of validating our antibodies and protocols for use in fresh or frozen tissue.
SignalStar Multiplex IHC Kits & Reagents haven’t yet been validated for use in mouse tissues. We’re in the process of validating mouse-reactive antibodies.
SignalStar Multiplex IHC Kits & Reagents haven’t yet been validated for use with antibodies outside of our menu. We’re in the process of developing custom solutions for using your own antibodies in the SignalStar Multiplex IHC assay.
SignalStar Multiplex IHC Kits & Reagents haven’t been validated for use in combination with direct conjugates. It’s likely possible to incorporate direct conjugates into your protocol. However, because the SignalStar reagents benefit from fluorescent signal amplification, there may be spectral bleed-through that results from using the assay with conjugates that are not amplified.
During the course of optimization, we've found that fluorescent staining may show higher %-positivity than chromogenic staining. To ensure any excess staining is specific, confirm that the correct subcellular localization and co-localization with other stains are demonstrated. For example, if all CD8+ cells are CD3+, any excess CD8+ staining compared to the chromogenic is most likely correct.
For Imaging Round 1, the staining should show robust signal when imaged up to 8 hr post completion of staining. For Imaging Round 2, imaging should be performed as close to the completion of staining as possible, but should remain robust for up to 8 hr.
The SignalStar Multiplex IHC Kits & Reagents have been optimized with respect to fluorophore pairing and order of antibodies. As tissues vary in quality and expression level of targets, increasing the concentration of antibodies in your panel by 2-fold or decreasing by 0.5 fold can help achieve optimal signal in your experiments.
Any tissue shown to be positive for each target via chromogenic IHC can serve as a positive control tissue. Each target will therefore require a positive control, which may sometimes necessitate multiple controls. For optimal comparison, the sections should be as close to serial as possible.
For any additional questions, please contact our SignalStar group directly at [email protected].