Improvement of deficient natural killer activity and delayed bactericidal activity by a thiol proteinase inhibitor, E-64-d, in leukocytes from Chediak-Higashi syndrome patients in vitro.
We previously reported that administration of a potent calpain inhibitor, E-64-d, which protects protein kinase C (PKC) from proteolysis, in a mouse model of Chediak-Higashi syndrome (CHS) (beige mice), decreases its susceptibility to Staphylococcus aureus infection. In the present study, we examined the in vitro effect of E-64-d on both deficient natural killer (NK) and delayed bactericidal activities of leukocytes from six CHS patients. Our results showed that pretreatment of peripheral blood mononuclear cells (PBMCs) obtained from CHS patients with E-64-d (1 microg/ml) significantly enhanced NK activity against K562 cells. The delayed bactericidal activity of polymorphonuclear cells (PMNs) against S. aureus also showed marked improvement. This was recovered to almost normal levels when PMNs were pretreated with E-64-d (1 microg/ml). On the other hand, the same concentration of E-64-d did not affect either the NK or bactericidal activity of normal controls. In addition, we confirmed that following E-64-d treatment, the abnormal down-regulation of PKC activity after concanavalin A (Con A) stimulation was eliminated in PBMCs obtained from CHS patients. To examine whether PKC is involved in the NK cell-mediated cytolysis and bactericidal activity of PMNs, two potent PKC inhibitors, chelerythrin and GO6976, were used. We found that chelerythrin inhibits NK activity of normal PBMCs in a dose-dependent manner, and GO6976 inhibits NK activity at doses that inhibit Ca(2+)-dependent PKC isozymes. These inhibitors also suppressed the bactericidal activity of PMNs against S. aureus. Taken together, our findings suggested that E-64-d improved the compromised NK and bactericidal activity of leukocytes from CHS patients by reversing the down-regulation of PKC activity.
Tanabe
Fuminori
F
Department of Human Science, Faculty of Medicine, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi 409-3898, Japan. ftanabe@yamanashi.ac.jp
Kasai
Hirotake
H
He
Limin
L
Kin
Tomohiro
T
Fujikado
Takashi
T
Kumamoto
Toshihide
T
Hara
Toshiro
T
Iwata
Tsutomu
T
Ito
Masahiko
M
D053119:Benzophenanthridines / Q000494:pharmacology; D002227:Carbazoles / Q000494:pharmacology; D045744:Cell Line, Tumor; D002609:Chediak-Higashi Syndrome / Q000150:complications / Q000276:immunology*; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology*; D005260:Female; D006801:Humans; D007694:Killer Cells, Natural / Q000187:drug effects* / Q000276:immunology / Q000382:microbiology; D007930:Leucine / Q000031:analogs & derivatives* / Q000494:pharmacology; D008297:Male; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D013203:Staphylococcal Infections / Q000276:immunology*; D013211:Staphylococcus aureus / Q000276:immunology*
D053119:Benzophenanthridines; D002227:Carbazoles; D015853:Cysteine Proteinase Inhibitors; D047428:Protein Kinase Inhibitors; C081021:Go 6976; C016299:chelerythrine; D011493:Protein Kinase C; D007930:Leucine; C024974:E 64