Help & FAQs: Flow Cytometry Kits

  • What Fc blocking reagent does R&D Systems recommend for Flow Cytometry?
  • The Fc blocking reagent ideally should be IgG from the same species as the cells which are being stained.
  • What is R&D Systems doing to reduce its use of packaging from non-renewable resources? R&D Systems should consider re-using styrofoam boxes that are in good condition after delivery.
  • Environmental stewardship is important to R&D Systems and its employees. R&D Systems regularly explores "green" options. First and foremost, the energy expended to ship back the styrofoam box is more detrimental to the environment than having the facility re-use or recycle it. Our stance is to encourage our customers to implement a recycling program locally and we can identify a recycling center for styrofoam nearest your facility if necessary. At R&D Systems we have chosen to reduce the use of styrofoam as much as possible by: Doing extensive stability testing in order to determine which products can be shipped with minimal packaging at ambient temperatures, Converting the use of non-recyclable packaging materials to recyclable plastics, cardboard, or biodegradable materials, and Continuing to investigate alternatives to dry ice shipments, the use of re-usable containers, and gel packs that allow for smaller styrofoam containers. Employees were key to initiating a recycling program at our facilities. Internally, we recycle paper, plastic, cardboard, aluminum, glass, and styrofoam.
  • What is the molecular weight of Fluorescein Isothiocyanate (FITC)?
  • The molecular weight of FITC is 389.38 Daltons. However, R&D Systems uses 5- (and 6-) Carboxyfluorescein (CFS) for antibody conjugation, which has a molecular weight of 473 Daltons.
  • What is the molecular weight of R-Phycoerythrin (PE) ?
  • PE is a 240 kDa protein with 23 phycoerythrobilin chromophores per molecule. Typically, only one PE molecule is conjugated to an antibody.
  • What type of tubes do you suggest using for staining in flow cytometry?
  • We reccommend the use of Falcon™ polystyrene tubes.
  • Why does the Biotinylated Fluorokine® kit protocol say not to wash the cells after adding the Fluorokine reagent?
  • This kit is designed to perform an amplification reaction. It is extremely important not to wash the cells before adding the avidin-FITC reagent. When the Fluorokine is added to the cells, some of it binds to receptors on the cell surface, and some remains as excess in the solution. When the avidin-FITC reagent is added to the reaction, some of it will bind to the biotinylated Fluorokine which has bound to the cell surface receptors. However, since each avidin-FITC molecule has the ability to bind 4 biotin molecules, the avidin-FITC bound to the surface of the cell also binds to some of the excess Fluorokine in the solution, which then binds more avidin-FITC in a cascade of reactions. This amplification reaction does not increase background staining, nor does it compromise the specficity of the reaction. It does mean that Biotinylated Fluorokine kits are less quantitative than flow cytometry performed with a specific antibody, but the benefits are that you can detect very low levels of receptors and you can detect all receptors that bind the biotinylated cytokine provided in the kit.