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Modulation of pokeweed mitogen-induced B cell differentiation by polymorphonuclear cells: effects of bacterial
C Tortorella1, A Ottolenghi, A Testa
1Department of Internal Medicine, University of Bari Medical Faculty, Italy.
Abstract:
The capacity of polymorphonuclear (PMN) cells to release several cytokines stresses the potential immunomodulatory role of these cells. The effects mediated by purified PMN cell suspensions on pokeweed mitogen (PWM)-driven B cell differentiation was investigated. Results showed that the addition of increasing concentrations of resting PMN cells to peripheral blood mononuclear cell (PBMC) cultures gave rise to inhibition of immunoglobulin (Ig) production. At the same time, similar results were obtained using lipopolysaccharide (LPS)-pretreated PMN cells. In contrast, when LPS, at different concentrations, and PMN cells were both added to PBMC cultures an enhancement of IgG or IgM release in comparison with cultures treated with PMN cells only occurred at low PMN cell/PBMC ratios (1:20 and 1:10), which was maximal in the presence of 10 or 100 ng/ml LPS. This effect was probably mediated by LPS-induced monocyte stimulation, since the supplementation of LPS-activated monocyte supernatants to PMN cell/PBMC cocultures led to an Ig synthesis which mimicked that seen in similarly-treated PBMC cultures. These data suggest the occurrence of various in vitro modulatory effects in the interactions between PMN, LPS and lymphocytes in a PWM-induced B cell polyclonal responsiveness system.
Insights
Polymorphonuclear (PMN) cells can modulate immune responses. This study found that PMN cells can inhibit immunoglobulin production, but enhance it when combined with lipopolysaccharide (LPS) and monocytes.
Area of Science:
- Immunology
- Cell Biology
Background:
- Polymorphonuclear (PMN) cells are known to release cytokines, suggesting a role in immunomodulation.
- B cell differentiation is a key process in adaptive immunity, regulated by various cellular interactions.
- Understanding the interplay between different immune cells is crucial for deciphering complex immune responses.
Purpose of the Study:
- To investigate the immunomodulatory effects of PMN cells on B cell differentiation.
- To examine how PMN cells interact with lipopolysaccharide (LPS) and other immune cells to influence immunoglobulin production.
Main Methods:
- Purified PMN cell suspensions were added to peripheral blood mononuclear cell (PBMC) cultures.
- Pokeweed mitogen (PWM) was used to drive B cell differentiation.
- Lipopolysaccharide (LPS) was used to stimulate monocytes and PMN cells.
- Immunoglobulin (IgG and IgM) production was measured.
Main Results:
- Resting and LPS-pretreated PMN cells inhibited immunoglobulin production in PWM-stimulated PBMC cultures.
- At low PMN cell/PBMC ratios, LPS enhanced IgG and IgM release, particularly with 10-100 ng/ml LPS.
- LPS-induced monocyte stimulation appeared to mediate the enhancement of Ig synthesis.
Conclusions:
- PMN cells exhibit diverse in vitro modulatory effects on B cell responses.
- The interaction between PMN cells, LPS, and lymphocytes can lead to varied outcomes in immunoglobulin production.
- Monocyte activation by LPS plays a significant role in the observed enhancement of Ig synthesis in co-cultures.