Phosphorylation Artifacts from Pre-Staining Surface Antibodies

Symptom

Intracellular phosphorylation signals are artifactually elevated or altered when surface antibodies are added before fixation. Antibody binding to surface antigens triggers unwanted intracellular signaling cascades that confound phospho-flow results.

1. 1 Surface antibody binding activates receptor-mediated signaling pathways
2. 2 Antibody cross-linking of surface antigens induces phosphorylation cascades
3. 3 Time lag between antibody addition and fixation allows signal transduction
4. 4 Fc receptor engagement by antibodies triggers non-specific phosphorylation events
5. 5 Temperature-dependent signaling continues during surface staining incubation

1. 1 Fix cells BEFORE adding surface antibodies when analyzing phospho-targets
2. 2 Use BioLegend True-Phos Perm Buffer protocol with fixation preceding all staining
3. 3 Work on ice (4°C) to minimize signaling if surface staining before fixation is unavoidable
4. 4 Minimize time between surface antibody addition and fixation (<5 minutes)
5. 5 Use Fab fragments instead of whole antibodies to reduce cross-linking effects
6. 6 Validate that surface markers do not alter phosphorylation of targets of interest

Related Video (2)

BioLegend ★ 82

Surface and Intracellular Cytokine Staining for Flow Cytometry

"Directly covers surface and intracellular staining workflow with fixation and permeabilization steps where pre-staining surface antibody artifacts would occur"

BD Biosciences ★ 71

Cell Preparation for Flow Cytometry

"Addresses cell preparation best practices for flow cytometry, including proper handling before staining to avoid artifactual signaling activation"