A researcher is interested in performing indirect immunofluorescence microscopy in human tissue using an antibody raised in goats that can detect a human protein called PCNT. Which of the following antibodies would better work as the secondary antibody in this experiment? Goat anti-goat linked to Cy3 Rat anti-goat linked to Cy3 Human anti-human linked to Cy3 Goat anti-human linked to Cy3

Rat anti-goat linked to Cy3

Explanation:

Indirect immunofluorescence microscopy is a technique used to localize endogenous marker proteins, having this approach high sensitivity. Secondary antibodies are produced by immunization of the target species with antibodies of one 'second' species. In a standard immunofluorescence assay, the secondary antibodies are linked to fluorophores and incubated with the primary antibody. In this case, the Cy3 fluorescent probe is used for labeling secondary antibodies, it is a fluorophore that absorbs light at 550 nm and emits at 570 nm.

the answer would be 3