Mouse-on-Mouse (MOM) Background

Symptom

High background staining when using mouse primary antibody on mouse tissue. Secondary antibody binds endogenous mouse IgG throughout the tissue, creating non-specific signal.

1. 1 Secondary antibody raised in same species as sample tissue (e.g., anti-mouse secondary on mouse tissue)
2. 2 Secondary antibody binds endogenous IgG present in tissue sections
3. 3 No secondary-only control performed to identify source of background

1. 1 Switch to primary antibody raised in different species (e.g., use rabbit antibody like α-Smooth Muscle Actin D4K9N #19245 instead of mouse antibody on mouse tissue)
2. 2 Use species-matched detection reagent for alternative primary (SignalStain Boost #8114 for rabbit primary eliminates MOM background)
3. 3 Always include control slide stained without primary antibody to confirm secondary antibody is source of background
4. 4 If mouse primary is essential, perform biotin block after normal blocking and before primary antibody incubation

Related Video (3)

Bilibili (China-Accessible Mirrors) ★ 85

Immunohistochemistry on Paraffin-Embedded Sections (CST Demo)

"CST IHC demo on paraffin sections covers the same protocol context where mouse-on-mouse background arises, including background-blocking and antibody selection steps."

Cell Signaling Technology ★ 78

Immunohistochemistry Protocol for Paraffin embedded Tissue Sections

"CST IHC protocol video provides the authoritative procedure context for troubleshooting secondary antibody species issues and background."

Bilibili (China-Accessible Mirrors) ★ 62

Complete IHC Immunohistochemistry Protocol for Beginners

"Comprehensive beginner IHC walkthrough helps understand where secondary antibody binding and blocking steps fit in the workflow."