Anti-Fluorescein/Oregon Green®, Rabbit IgG Fraction, Alexa Fluor® 488 Conjugate can be used to enhance the green-fluorescent signal of the fluorescein or Oregon Green® hapten with the superior photostability of the Alexa Fluor® 488 dye while utilizing existing fluorescein-labeled probes and fluorescein-compatible optics. This strategy is utilized in the Alexa Fluor® 488 Signal Amplification Kit for Fluorescein-Conjugated Probes (A11053). This antibody also enables the use of fluorescein or Oregon Green® dyes as haptens instead of biotin. Unlike biotin, which is an endogenous ligand in mitochondria, dye-based haptens permit background-free staining of cells and tissues and a sensitive alternative to biotin-streptavidin methods for ELISAs.