Immunophenotyping using gold or silver nanoparticle-polystyrene bead conjugates with multiple light scatter

Background: The type of antibody-conjugated polystyrene (PS) latex beads fo r use as light scatter shift agents for targeted lymphocyte populations in whole blood has been expanded to include gold and silver nanoparticle-amino dextran-PS latex bead conjugates with antibodies. The linkers between antib ody and colloidal metal were an aminotrithiol ligand or aminodextran polyme r molecules. Methods: A modified flow instrument, including forward light scatter (FS), side light scatter (SS), light scatter at other intermediate angle ranges, LMALS (10-20 degrees) and UMALS (20-65 degrees) was used for simultaneous b ead probe measurements. A conventional flow cytometer was used in simultane ous bead-fluorescent marker experiments. Results: Two mutually exclusive cell populations, CD4+ and CD8+ lymphocytes , have been simultaneously enumerated in blood by using a mixture of CD4-PS , CD8-Au-PS or CD4-Au-PS, CD8-PS beads, and one laser line, 633 run, excita tion. Similar measurements were made with mixtures of CD4-PS, CD8-Ag-PS or CD4-Ag-PS, CD8-PS beads. Also, simultaneous use of bead and fluorescent mar kers mixed with whole blood was demonstrated with. CD4-PS beads and with th e CD4-RD1/CD8-FITC dual marker. Conclusions: Enumeration of CD4 and CD8 lymphocytes in whole blood by light scatter parameters only compared well with standard analyses with fluoresc ent markers. In simultaneous bead-fluorescent marker labeling of lymphocyte s, the labeled bead had to be mixed first with cells in whole blood. Cytome try 41:298-307, 2000. (C) 2000 Wiley-Liss, Inc.