Time phycoerythrin

The effects of CVS on the numbers of T-cell subsets were examined on day 9 at the time of tumor i.v. rechallenging, Fig. (6)-Protocol B. Cells were stained with fluorescein 5-isothiocyanate (FITC)-, phycoerythrin (PE)-conjugated and/or biotinylated mAb and were additionally stained with RED-613-streptavidin for flow-cytometric three-color analysis. 

A real-time spectral data monitor was placed in operation. The monitor consists of an independent microprocessor-based system that acquires real-time spectral data and additional housekeeping information flowing through the CAMAC/HP computer-interface lines. The complete laser-induced fluorescence spectrum produced by each laser shot is displayed in real time. The system also provides a two-channel output to an analog chart recorder that produces two profile traces (usually the laser-induced phycoerythrin and chlorophyll a spectral response peaks). 

Smith, S.E., Orta-Ramirez, A., Ofoli, R.Y., Ryser, E.T., and Smith, D.M. 2002. R-phycoerythrin as a time-temperature integrator to verify the thermal processing adequacy of beef patties. Journal of Food Protection 65 814-819. 

Fig. 6. Effect of protein L injections on CD5+ B cells in the spleen. Transgenic mice expressing human Igs [46] were injected intraperitoneally five times with 1 mg of protein L every other day. On day 21, splenic lymphoid cell subpopulations were identified by immunofluorescent staining in control, HEL- and protein-L-treated transgenic mice. Splenocytes were stained with Cy-chrome-labeled anti-mouse B220 monoclonal antibody and phycoerythrin-labeled anti-mouse CD5 monoclonal antibody. All monoclonal antibodies and their corresponding isotype controls were purchased from BD PharMingen. The treatment did not affect B1 cells in the spleen.

The phycobiliproteins are hard to beat as extremely bright antibody labels for fluorescence analysis of cell surface antigens by flow cytome-try 15,16 These bacterial photosynthetic macromolecules each have up to 34 individual bilin fluorophores wrapped within the polypeptide structure. An example is R-phycoerythrin (R-PE), which has an extinction coefficient of 2 X 10 L/mol cm and a quantum yield of 0.68. Usually there is room for only one PE molecule per antibody, because the size of an R-PE label is 1.5 times that of an IgG antibody. The large size of the complex reduces the kinetics of binding to cell surface antigens, and some intracellular markers are inaccessible to the R-PE-labeled antibody. For intracellular measurements, lower molecular mass fluorophores (<1 kDa) are usually preferred. 

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