Table I.

Effect of various protease inhibitors on sCD100 releasea

InhibitorSpecificityPercent InhibitionbTested atc
AprotininSerine proteases25200 KUV/ml
ChymostatinSerine proteases (chymotrypsin)2120 μM
E-64Cysteine proteases3010 μM
EDTAMetalloproteases655 mM
EGTAMetalloproteases555 mM
HgCl2Cysteine proteases00.5 mM
LeupeptinSerine/cysteine proteases050 μg/ml
PepstatinAspartic proteases01 μg/ml
1,10-PhenanthrolineMetalloproteases0d5 mM
PhosphoramidonMetalloproteases (CD10)1250 μM
PMSFSerine/cysteine proteases0d2 mM
Soybean trypsin inhibitorSerine proteases (trypsin)0100 μg/ml
TPCKSerine proteases (chymotrypsin)0d50 μM
  • a Biotinylated Jurkat cells were cultured for 90 min in complete culture medium at 37°C supplemented with various protease inhibitors. Supernatants were then collected and CD100 was immunoprecipitated with specific mAbs. sCD100 release was evaluated by scanning densitometry after SDS-PAGE, blotting with HRP-conjugated streptavidin and ECL detection.

  • b Cells incubated in medium alone were used as control (0% inhibition). Results are representative of three independent experiments.

  • c Standard effective concentrations of inhibitors were used. Lack of toxicity was determined by trypan blue staining and the percentage of viable cells was always >90%.

  • d These inhibitors enhanced sCD100 release.