Non-specific Antibody Binding via Fc Receptors

Symptom

Elevated background staining on myeloid cells (monocytes, macrophages, dendritic cells, granulocytes) in bone marrow, blood, spleen, or in vitro myeloid cultures. False-positive signals not blocked by standard washing.

1. 1 Fcγ receptors on myeloid cells bind to antibody Fc regions independently of antigen specificity
2. 2 Bone marrow, blood, and spleen samples enriched in Fc receptor-expressing cells
3. 3 In vitro differentiated myeloid cultures express high levels of scavenger receptors
4. 4 Tandem dyes (PE/Dazzle 594, APC/Fire 750, PE/Cy7, PE/Cy5, PerCP/Cy5.5, especially APC/Cy7) bind monocytes/macrophages independent of Fc receptors

1. 1 Include FcR blocker (Fc receptor blocking reagent) in staining protocol when working with myeloid-enriched samples
2. 2 Add True-Stain Monocyte Blocker to minimize tandem dye binding to monocytes and macrophages
3. 3 Pre-incubate cells with blocking reagent for 10-15 minutes before antibody staining
4. 4 Use F(ab')2 fragments or Fab fragments lacking Fc region for critical markers
5. 5 Avoid assigning critical dim markers to APC/Cy7 when analyzing monocyte/macrophage-rich samples

Related Video (3)

Bilibili (China-Accessible Mirrors) ★ 85

Flow Cytometry Complete Workflow: Sample to Analysis

"Complete flow cytometry protocol covering sample preparation and staining steps where Fc receptor blocking is critical to prevent false positive background"

BioLegend ★ 78

Surface and Intracellular Cytokine Staining for Flow Cytometry

"Surface and intracellular staining protocol for flow cytometry that directly addresses antibody staining procedures on cells where Fc receptor binding occurs"

Bilibili (China-Accessible Mirrors) ★ 72

Zhejiang University Senior's Flow Cytometry Hands-On Tutorial

"Hands-on flow cytometry tutorial demonstrating experimental workflow and protocol execution where Fc receptor issues manifest in myeloid cell populations"