[Histonet] mouse-on-mouse kit and non-specific staining

[iris oren]

Hi, 

I am using a mouse monoclonal antibody on PFA-fixed mouse brain slices, and the 
Vector mouse-on-mouse kit. My background with the provided avidin-biotyn is 
ridiculously high even after blocking endogenous biotyn. However, I get an 
overall low background using an Alexa-conjugated goat anti-mouse (with the 
slices pre-treated in Normal Goat Serum). The problem is that in the control 
sections with no primary, I still get staining of isolated cells.
Does anyone have any thoughts/experience/recommendation with using an Alexa 
conjugated anti mouse IgG secondary on mouse tissue (with a mouse-on-mouse 
block)?

Many thanks in advance
Iris