[Down-regulation effect of McAb HIM82 on Ca2+, protein kinase C, protein tyrosine kinase signal pathway of neutrophils].
OBJECTIVE
To study the control effects of HIM82 and HIM70 on reactive oxygen species (ROS) released from respiratory burst of neutrophils (Np), and the action of HIM82 on relevant signal transduction pathway.


METHODS
The experimental group (combining with McAb) was compared with the control group with regard to the ROS level, activity of G protein, intracellular [Ca2+] level, the activities of PKC and PTK in activated Np to interpret the mechanism by which the McAb down-regulated the respiratory burst.


RESULTS
The positive rate of Np combined with HIM82 was shown over 95% using indirect immunofluorescence assay (control group was 0). The generation of superoxide anion and hydrogen peroxide from PMA-treated Np were decreased by 55% (P < 0.01) and 32% (P < 0.01) with 30 micrograms/ml HIM82. The amount of H2O2 produced in FMLP or SP-stimulated Np were decreased by 16% (P < 0.01) and 37% (P < 0.01) respectively. A similar effect of HIM70 on Np was observed. Furthermore, the inhibition of H2O2 in FMLP-activated Np affected by PT, a specific inhibitor for G-protein, and in HIM82 was 42% and 60% separately, and that with both PT and HIM82 was 85%. It was suggested that HIM82 could enhance the inhibition effect of PT on G-protein. The intracellular [Ca2+] level of Np stimulated with FMLP was decreased by 85%, and that of Np activated with PMA by 100% nearly in the present of HIM82. The activities of PKC and PTK in PMA-stimulated Np were decreased by 23% (P < 0.05) and 35% (P < 0.05) separately when treated with HIM82.


CONCLUSIONS
The McAb HIM82 could down-regulate the ROS produced from activated Np. The mechanism of decreasing ROS may be involved in down-regulating Ca(2+)-PKC and PTK signal transduction pathway activities that are upstream control systems for NADPH oxidase activation.
Fa
X
X
Institute of Hematology, CAMS and PUMC, Tianjin 300020.
Jiang
X
X
Lu
S
S
D000911:Antibodies, Monoclonal; D002118:Calcium / Q000378:metabolism*; D015536:Down-Regulation; D019204:GTP-Binding Proteins / Q000378:metabolism; D006801:Humans; D009504:Neutrophils / Q000378:metabolism*; D011493:Protein Kinase C / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D016897:Respiratory Burst; D015398:Signal Transduction
D000911:Antibodies, Monoclonal; D017382:Reactive Oxygen Species; D011505:Protein-Tyrosine Kinases; D011493:Protein Kinase C; D019204:GTP-Binding Proteins; D002118:Calcium