If you can tolerate several washes, you can use a biotin on the Ab, then an unlabeled streptavidin step (1ug/10x6 cells). Wash and add labeled biotin at same concentration. Avidin binds four biotins, this sandwich allows you to get 3 labeled molecules per Ab. I have had great success with it, at the level of 900-1800 target molecules per cell. Good luck, Steve McClellan BeckmanCoulter cytometry ----- Original Message ----- From: Jeff Haug <jhaug@im.wustl.edu> To: Cytometry Mailing List <cytometry@flowcyt.cyto.purdue.edu> Sent: Thursday, February 24, 2000 6:40 PM Subject: Streptav. Second makes signal brighter? > > I have always been told that a biotin conjugated primary antibody followed > by a fluorescent conjugated streptavidin secondary antibody is a method > that should make a low density signal more bright. > > Is this really true or just theoretical? > > I ask this question because when I have performed comparisons between > direct and indirect staining methods I have never seen much difference. > > Thanks, Jeffrey > >
This archive was generated by hypermail 2b29 : Sat Mar 10 2001 - 19:31:09 EST