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In vitro and in vivo effects produced by the immunomodulating agent RU 41740 on human polymorphonuclear leukocytes in
A el Abbouyi1, M Roch-Arveiller, C Marchiani
1Laboratoire de Pharmacologie et de Biochimie A, Hôpital Cochin, France.
Abstract:
The activity of RU 41740, a glycoprotein extract from Klebsiella pneumoniae has been investigated on some polymorphonuclear (PMN) functions. Chemotaxis, random migration and oxidative metabolism (assessed by chemiluminescence, O2 consumption and O2- generation) were studied in parallel. PMN were collected from adult and aged human volunteers. Experiments were performed either in vitro or in vivo in a double blind placebo assay. In both PMN populations RU 41740 enhanced oxidative metabolism either in in vivo or in vitro experiments. However, a higher and dose-related activity was observed on PMN collected from the younger subjects whereas maximal effective concentration was reached earlier with PMN collected from aged subjects. RU 41740 did not modify random migration but inhibited chemotaxis of PMN collected from the younger population in a dose-related manner. These data corroborated previous results observed on PMN collected from various animal species and suggested an interaction of RU 41740 on PMN membrane. Moreover drug-induced macrophage and lymphocyte stimulation might also explain, at least in part, the in vivo effects described in this study. Thus RU 41740 could partly account for the protective effects exerted against bacterial and fungal infections through its activity on PMN functions.
Insights
RU 41740, a Klebsiella pneumoniae extract, enhances immune cell oxidative metabolism in humans. This glycoprotein modulates polymorphonuclear (PMN) functions, potentially boosting protection against infections.
Area of Science:
- Immunology
- Microbiology
- Pharmacology
Background:
- Polymorphonuclear (PMN) cells are crucial for innate immunity.
- Klebsiella pneumoniae extracts have shown immunomodulatory potential.
- Understanding the effects of novel compounds on immune cell function is vital for developing new therapeutics.
Purpose of the Study:
- To investigate the effects of RU 41740, a glycoprotein extract from Klebsiella pneumoniae, on human polymorphonuclear (PMN) functions.
- To assess the impact of RU 41740 on PMN chemotaxis, random migration, and oxidative metabolism in both adult and aged individuals.
- To explore the potential in vivo and in vitro mechanisms of RU 41740's immunomodulatory activity.
Main Methods:
- Human PMNs were isolated from adult and aged volunteers.
- In vitro and in vivo (double-blind placebo assay) experiments were conducted.
- PMN functions including chemotaxis, random migration, and oxidative metabolism (chemiluminescence, O2 consumption, O2- generation) were measured.
Main Results:
- RU 41740 significantly enhanced oxidative metabolism in PMNs from both age groups, with a more pronounced, dose-related effect in younger subjects.
- Maximal effective concentration for oxidative metabolism enhancement was reached earlier in PMNs from aged subjects.
- RU 41740 inhibited PMN chemotaxis in a dose-related manner in younger subjects but did not affect random migration.
Conclusions:
- RU 41740 modulates human PMN functions, particularly oxidative metabolism and chemotaxis.
- The observed effects suggest an interaction with the PMN membrane and potential stimulation of macrophages and lymphocytes.
- RU 41740 may contribute to protective effects against bacterial and fungal infections by enhancing PMN functions.