A MORPHOLOGICAL ANALYSIS OF BINDING OF A HYDROPHOBIC PROBE TO CELLS

Abstract

Arylaminonaphthalenesulfonates are used as hydrophobic probes because of the enhanced fluorescence quantum yield of these compounds in media of low dielectric constant (1-3). One such probe, 8-anilino-l-naphthalenesulfonate (ANS), forms noncovalent fluorescent complexes with human leukocytes (4) and thus can be used to detect hydrophobic components on and within these cells. We report here a morphological analysis of the binding of ANS to human leukocytes and plasma cells performed by fluorescence microscopy. MATERIALS AND METHODS Leukocytes were obtained from the buffy coat of heparinized human venous blood of three normal subjects by sedimentation at 500 g for 15 min at 20 °C. Plasma cells were obtained from a tumor that was excised from a patient with multiple myeloma. Cells were washed three times by centrifugation in 0.05 M phosphate-0.15 M NaCl, pH 7.2 (PBS) and were finally suspended in 2.5 X 10-3 M ANS (K & K