Immunfluoreszcencia

Immunfluoreszcencia is a laboratory technique that uses antibodies labeled with fluorescent dyes to detect specific antigens in cells or tissue sections. In direct immunofluorescence, a fluorescently tagged antibody binds directly to the target antigen. In indirect immunofluorescence, an unlabeled primary antibody binds the antigen and a fluorescently labeled secondary antibody recognizes the primary antibody, often providing stronger signal and greater flexibility.

Samples are typically fixed to preserve structure, and may be permeabilized to allow antibody access. Stained specimens are examined with fluorescence microscopy, often using filter sets matched to the fluorophores’ excitation and emission spectra. Confocal microscopy or other advanced imaging methods can improve resolution and allow optical sectioning. Common fluorophores include fluorescein isothiocyanate (FITC), Alexa Fluor dyes, and rhodamines, enabling multi-color labeling to study the co-localization of several proteins.

Applications span clinical diagnostics and basic research. Immunfluoreszcencia is used to localize proteins within cells or tissues, map receptor distribution, and identify infectious agents. It also serves in autoimmune disease diagnostics by revealing characteristic staining patterns. In research, it supports investigations into cellular processes, signaling pathways, and protein interactions.

Limitations include potential nonspecific binding, autofluorescence from tissues, and sensitivity to fixation methods. Proper controls, such as positive and negative samples, are essential. The technique has evolved alongside advances in fluorophores and imaging platforms and remains a core tool in immunology, pathology, and cell biology. The English term is immunofluorescence; in Spanish and Portuguese spellings such as inmunofluorescencia or imunofluorrescência are common.