Mouse-on-Mouse (MOM) Background (Immunohistochemistry (CST Guide))

Question

Accepted Answer

High background staining when using mouse primary antibody on mouse tissue. Secondary antibody binds endogenous mouse IgG throughout the tissue, creating non-specific signal. Common causes: 1) Secondary antibody raised in same species as sample tissue (e.g., anti-mouse secondary on mouse tissue) 2) Secondary antibody binds endogenous IgG present in tissue sections 3) No secondary-only control performed to identify source of background Solutions: 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) Use species-matched detection reagent for alternative primary (SignalStain Boost #8114 for rabbit primary eliminates MOM background) 3) Always include control slide stained without primary antibody to confirm secondary antibody is source of background 4) If mouse primary is essential, perform biotin block after normal blocking and before primary antibody incubation