Abstract
Staphylococcal serine proteinase (SSP) can influence various functions of human polymorphonuclear leukocytes (PMNL) including chemotaxis and phagocytosis. Since the rise in intracellular free calcium concentration is an important step in signal transduction leading to phagocyte activation, we tested the ability of SSP to increase the intracellular free calcium concentration in human PMNL using the fluorescent calcium indicator Fura-2AM. PMNL isolated from healthy donors responded to SSP in the concentration range of 10 to 100 micrograms/ml. The highest Ca2+ rise (104 +/- 47 nM) was observed for 10 micrograms/ml SSP. It was mainly dependent (81 +/- 11%) on extracellular calcium influx, however, SSP mobilized 68 +/- 7% of Ca2+ from intracellular calcium stores. Boiling of SSP or preincubation with phenylmethylsulphonylfluoride (an serine proteinase inhibitor) did not change its ability to increase intracellular free calcium concentration in PMNL. It suggests that active center of SSP is not responsible for Ca2+ mobilization. Finally, PMNL responded to each of three consecutive stimulations with SSP independently of the presence of high or low extracellular Ca2+ concentration. This may be an additional mechanism responsible for activation of human PMNL and degradation of alveolar walls during the staphylococcal infection in the lower airways.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
