Immunofluorescence is a type of experiment, that involves the binding of the primary antibody to the target protein located in a fixed cell or a tissue section. Following this specific binding, a fluorescent detection method is used to visualize the localization of the protein of interest.
Direct Immunofluorescence staining
When performing a direct staining, the primary antibody is directly conjugated to the fluorophore.
Indirect Immunofluorescence staining
The second type of IF staining utilises a number of secondary or tertiary antibodies, which have multiple labels and in turn bind to the primary antibody, leading to amplification of the signal. These additional antibodies provide better staining in cases when the target protein isn't very abundant, making this technique more versitale.