Immunofluorescence stain on spleen tissue section

[R00445109]

I have stained a spleen tissue section by immunofluorescence stain but I observed high autofluorescence such that I can't see the target I stained. How can I solve this problem?

and my method is indirect IF.
1st ab is rabbit anti-rat MPO 500x diluted.
2nd Ab is anti-rabbit -FITC 1000x diluted.
i use fluorescence microscopy to observe tissue, but autofluorescence is too high that i can't distinguish what area is stained.
should i change blocking buffer or wash buffer?

[wallywoo]

Autofluorescence can be quenched by using DAB on the section for 10 minutes RT after blocking step. It can be purchased from vector labs.