Dear Simon,

The Alexa dyes are brighter and fade less than FITC (the FITC equivalent is Alexa488). When antibody labelling I have found that mounting the slide in PBS (Phosphate buffered saline) WITHOUT antifade gives the brightest fluorescence - even in these conditions Alexa 488 has little fading. There are other ways and means of amplifying the signal that perhaps others that have more experience with could comment on.

Regards, Alan Hibbs.

BIOCON, specialists in confocal microscopy         ABN: 46 196 908 558
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Dr. Alan R. Hibbs                                                                        FAX: 61 3 8660 2290	


-----Original Message-----
From:   Finney, Simon [SMTP:[log in to unmask]]
Sent:   Saturday, May 05, 2001 2:34 AM
To:     [log in to unmask]
Subject:        Fluorescent dyes

Dear All,

As a bit of a beginner, I would be grateful for some help in how best to
visualise an antigen of very low intensity. Flow cytometry requires the use
of PE as this is a log brighter than any FITC etc but when I use it in
confocal it blaches really badly (sufficiently so that I can't take an
accumulated scan). Does any one have suggestions for a bright secondary
system ??

Simon Finney