Tyramide signal amplification method in multiple-label immunofluorescence confocal microscopy

The tyramide signal amplification (TSA) method has recently been introduced to improve the detection sensitivity of immunohistochemistry. We present t hree examples of applying this method to immunofluorescence confocal laser microscopy: (1) single labeling for CD54 in frozen mouse brain tissue; (2) double labeling with two unconjugated primary antibodies raised in the same host species (human immunodeficiency virus type 1 p24 and CD68) in paraffi n-biopsied human lymphoid tissue; and (3) triple labeling for brain-derived neurotrophic factor, glial fibrillary acidic protein, and HLA-DR in paraff in-autopsied human brain tissue. The TSA method, when properly optimized to individual tissues and primary antibodies, is an important tool for immuno fluorescence microscopy. Furthermore, the TSA method and enzyme pretreatmen t can be complementary to achieve a high detection sensitivity, particularl y in formalin-fixed paraffin-embedded archival tissues. Using multiple-labe l immunofluorescence confocal microscopy to characterize the cellular local ization of antigens, the TSA method can be critical for double labeling wit h unconjugated primary antibodies raised in the same host species, (C) 1999 Academic Press.