FITC-labeled ODN 1826 (sodium), a class B CpG ODN (oligodeoxynucleotide), is a TLR9 agonist. FITC-labeled ODN 1826 (sodium) can be used to evaluate CpG ODN cellular uptake and localization by confocal laser-scanning microscopy (excitation 495 nm, emission 520 nm) or flow cytometry.