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In vitro stimulation of polymorphonuclear cell adhesion by ribomunyl and antibiotic + ribomunyl combinations: effects
1Laboratoire de Bactériologie Virologie et Microbiologie Industrielle, Toulouse, France.
Abstract:
Several functions of polymorphonuclear cells (PMNs) require adhesion to occur. Various membrane proteins' functions such as CD18 (beta 2 chain of integrin), CD35 (CR1) and CD16 (F c gamma Receptor III) participate in adhesion. In vivo treatment with Ribomunyl (R), an immunomodulating agent, was shown to enhance adhesion and migration of PMNs. To explore the direct effect of R on PMNs, cells from healthy subjects were treated in vitro with R. A significant increase of PMN adhesion and expression of CD18 and CD35 molecules were observed with 50 and 100 micrograms/ml of R after 2 h incubation. However, R-treatment decreased the PMN reactivity towards anti-CD16 (F c gamma RIII) monoclonal antibody. The effect of R on adhesion and membrane molecule expression was independent of the presence of serum and of polymixin B. Thus, this effect cannot be due to lipopolysaccharide (LPS) contaminants and does not require interactions with serum components. In previous studies, it was shown that in vitro amoxicillin increased some PMN functions whereas josamycin decreased them. The in vitro incubation of PMNs with R and amoxicillin (100 micrograms/ml) potentiated the positive effect of amoxicillin on adhesion and the antibiotic counterbalanced the negative effect of R on CD16 expression. In addition, R compensated the negative effect of josamycin (100 micrograms/ml) on PMN adhesion and on CD18 and CD35 expression. This study indicates: (1) the direct effect of R on PMN adhesion and on expression of molecules involved in adhesive-mediated functions, and (2) the beneficial effect of the association of R with antibiotics which can stimulate PMN activity.
Insights
Ribomunyl (R) directly enhances polymorphonuclear cell (PMN) adhesion and expression of CD18 and CD35 molecules. This immunomodulator also positively interacts with antibiotics, improving PMN function and counteracting antibiotic-induced decreases in PMN activity.
Area of Science:
- Immunology
- Cell Biology
Background:
- Polymorphonuclear cells (PMNs) play a crucial role in immune responses, with their functions often dependent on cell adhesion.
- Adhesion involves various membrane proteins, including CD18, CD35, and CD16, which are critical for PMN migration and activity.
Purpose of the Study:
- To investigate the direct in vitro effects of the immunomodulating agent Ribomunyl (R) on PMN adhesion and the expression of key adhesion molecules.
- To evaluate the combined effects of Ribomunyl (R) with antibiotics like amoxicillin and josamycin on PMN functions.
Main Methods:
- Human PMNs from healthy subjects were treated in vitro with varying concentrations of Ribomunyl (R).
- Flow cytometry was used to assess the expression of CD18, CD35, and CD16 molecules on PMNs.
- PMN adhesion assays were performed to quantify changes in cell adherence.
Main Results:
- Ribomunyl (R) significantly increased PMN adhesion and the expression of CD18 and CD35 molecules at concentrations of 50 and 100 µg/ml after 2 hours.
- Conversely, Ribomunyl (R) treatment reduced PMN reactivity towards anti-CD16 monoclonal antibody.
- The effects of Ribomunyl (R) were independent of serum presence and polymyxin B, indicating no LPS contamination involvement.
- Co-incubation with amoxicillin potentiated the positive effects of Ribomunyl (R) on adhesion and counteracted its negative effect on CD16 expression.
- Ribomunyl (R) also compensated for the negative effects of josamycin on PMN adhesion and CD18/CD35 expression.
Conclusions:
- Ribomunyl (R) directly influences PMN adhesion and the expression of adhesion-related molecules.
- Combining Ribomunyl (R) with certain antibiotics may offer a beneficial strategy to enhance PMN activity and immune response.