Ligand-aminodextran-marker conjugates and uses thereof

A method for a single-measurement quantification of multiple populations of cells comprising:

• (a) providing between one to multiple pairs of selected cell populations, a first population of each said pair having a first binding partner density which is substantially equivalent to the density of a second binding partner on a second population of each said pair, said first binding partner being found only in said first cell population of each pair, and said second binding partner being found only in said second cell population of each pair, wherein each pair of cell populations has a different first binding partner and a different second binding partner than each other pair of cell populations comprising said multiple pairs;
• (b) providing for each first population a first ligand labeled directly with a phycobiliprotein or a phycobiliprotein-containing tandem dye, said first ligand capable of binding to said first binding partner and differing among each said first population;
• and said phycobiliprotein or tandem dye differing among each said first ligand;
• (c) providing for each second population a second ligand labeled with an aminodextran-(phycobihiprotein or phycobiliprotein-containing tandem dye) conjugate, said second ligand capable of binding to said second binding partner and differing among each said second binding partner;
• wherein within a pair of cell populations said phycobiliprotein or phycobiliprotein-containing tandem dye of said conjugate is the same as the phycobiliprotein or phycobiliprotein-containing tandem dye of the first ligand, and wherein the phycobiliprotein or phycobiliprotein-containing tandem dye of each pair of ligands is a different color;
• (d) incubating a biological sample comprising said multiple selected cell populations with each pair of said first and said second labeled ligands for a time sufficient to permit binding partner-labeled ligand complexes to form therebetween;
• (e) exciting each phycobiliprotein or phycobiliprotein-containing tandem dye in each said complex with a laser excitation line to cause it to fluoresce;
• and
• (f) measuring the intensities of fluorescent emissions of each said first cell population bound to each said labeled first ligand and the fluorescent emissions of each said second population bound to each said labeled second ligand in a single measurement using flow cytometry;
• wherein within each pair of cell populations, said first labeled ligand provides a fluorescent signal of the same color but quantitatively distinguishable intensity from that of the second labeled ligand, and wherein the cell populations are distinguished by detectable variations in label intensity and color.