Time-resolved fluorescence imaging (TRFI) far direct immunofluorescence ofPSA and alpha-1-antichymotrypsin in prostatic tissue sections

We have developed a direct immunofluorescence technique utilising chelates of the lanthanide ions europium and terbium conjugated to monoclonal IgGs ( Mabs) against prostate-specific antigen (PSA) and alpha-1-antiehymotrypsin (ACT) for the detection and quantification on the same tissue section. Stro ng signals without disturbance from tissue autofluorescence were demonstrat ed in paraffin sections of ten benign and six malignant prostate tissue spe cimens. The signal intensity increased Linearly with the amount of labelled Mab until epitope saturation began. The highest concentrations of bound Ig G in tissue sections were 27.3 fmol/pixel for ACT and 7.2 for PSA. Time-res olved fluorescence imaging (TRFI) offers an attractive method for histochem ical studies based on specific and quantitative detection of fluorescent la nthanide chelates.