cfse quenching?

Hello 
I have a microscopy/staining problem.

I have CFSE labeled T cells and transferred them into hosts which were
subsequently infected with Listeria monocytogenes.  I then made spleen
sections which were stained for:

1) anti B220 followed by anti rat alexa fluor 350
anti CD3 followed by biotin anti hamster Ig followed by SA alexa fluor
594

With this combination I can visualize green transferred T cells (CFSE),
blue B cells and red endogenous T cells using a multi-filter Leica
digital light microscope.

The second stain combo is
2) anti CD11b (Mac-1) followed by anti rat alexa fluor 350
anti Listeria monocytogenes followed by biotin anti rabbit Ig followed
by SA alexa fluor 594 

With this combination I can visualize blue macrophages and red Listeria
monocytogenes, but I CAN NOT visualize the green transferred T cells. 
Any thoughts as to why the second stain combination
negates/dilutes/quenches the CFSE labeled T cells that are visible in
the first stain combination?

Thanks,
Angie Mobley