What is the difference between primary and secondary immunofluorescence?

In primary fluorescence, one antibody coupled to a fluorophore that binds to the epitope is used, while in secondary fluorescence, a primary antibody is used to bind to the epitope and a secondary antibody coupled to a fluorophore is used to bind to the primary antibody. primary immunofluorescence is quicker, but secondary immunofluorescence is more widely used since it is more sensitive.