Final answer:
In immunofluorescence and flow cytometry, a fluorophore is typically coupled to an IgG antibody due to its high specificity and ease of use in these applications.
Step-by-step explanation:
In the context of immunofluorescence and flow cytometry techniques such as Lyocells, it is common for the fluorophore to be coupled to an IgG antibody. This is because IgG antibodies are widely used for their high specificity and ability to facilitate a variety of immune responses. Additionally, IgG is stable and can be easily tagged with a fluorescent dye, serving as the fluorescent antibody that binds to the target of interest, typically an antigen, in direct fluorescent antibody tests.