ISSN:
1432-0878
Keywords:
Fluorescent dyes
;
Concanavalin A
;
Lymphocyte transformation
;
Fluorometry
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary The hydrophobic fluorescent cell-membrane probe N-phenyl-1-naphthylamine (NPN) is a useful investigative tool for studies of early lymphocyte activation. NPN-labelled mouse thymus cells incubated with 5 μg/ml concanavalin A (Con A) for 30 min at 37° C gave a reproducible increase in mean cell-fluorescence intensity measured by microfluorimetry on 100 single cells. The dose-response curve was similar to that obtained by 3H-thymidine assay. Increased fluorescence was not observed in the presence of 10 mM α-methyl mannoside, 5mM sodium azide, 10−5 M cytochalasin B, or Ca2+-free culture medium.However, incubation with 10−5 M colchicine did not alter the probe response. Fluorescence change was also shown by spleen cells from a normal mouse but not from an athymic mouse, indicating T cell dependence of the response. Comparison with other lectins showed that increased fluorescence followed incubation with phytohaemagglutinin, and the non-mitogenic wheat germ lectin, but there was no change with succinyl-Con A, and decreased fluorescence with pokeweed mitogen. Use of fluorescent-labelled lectins showed that the NPN fluorescence change did not correlate with surface receptor patching and capping. Increased phospholipid-fatty acid turnover and subsequent increased membrane fluidity with alteration of molecular polarity are suggested as likely explanations of increased NPN fluorescence.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00235150
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