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Functions of multinucleated giant cells formed by fusing rat alveolar macrophages with lymphokines containing
Abstract:
Rat alveolar macrophages (AM) fused and formed multinucleated giant cells (MGC) when incubated with lymphokines released from mitogen-stimulated syngeneic lymphocytes. Several functions of these MGC populations were evaluated in vitro. MGC populations phagocytized opsonized sheep red blood cells to a lesser degree than unfused AM. The tumoricidal activity of MGC populations was compared with that of unfused AM after both populations had been treated with lipopolysaccharide (LPS) or lymphokines devoid of fusion factor activity. Results showed that MGC populations lost tumoricidal properties more rapidly than unfused AM. Treatment of MGC with LPS enhanced the production and release of lymphocyte-activating factor(s) (IL-1, interleukin 1) that augmented the blastogenic response of lymphocytes to phytohemagglutinin. These studies suggest that one possible function of MGC that lack phagocytic and tumoricidal properties may be in maintenance of granuloma formation by IL-1 production.
Insights
Rat alveolar macrophages fuse into multinucleated giant cells (MGC). These MGC show reduced phagocytosis and tumoricidal activity but enhance IL-1 production, potentially maintaining granuloma formation.
Area of Science:
- Immunology
- Cell Biology
Background:
- Rat alveolar macrophages (AM) can fuse to form multinucleated giant cells (MGC).
- Lymphokines from stimulated lymphocytes induce this fusion process.
Purpose of the Study:
- To evaluate the functions of MGC derived from rat AM.
- To compare MGC functions with unfused AM.
Main Methods:
- Incubation of rat AM with lymphokines to form MGC.
- In vitro assessment of phagocytosis of opsonized sheep red blood cells.
- Evaluation of tumoricidal activity after treatment with LPS or lymphokines.
- Measurement of lymphocyte-activating factor (IL-1) production.
Main Results:
- MGC exhibited decreased phagocytic capacity compared to unfused AM.
- MGC showed a more rapid loss of tumoricidal properties than unfused AM.
- LPS treatment of MGC increased IL-1 production, enhancing lymphocyte blastogenesis.
Conclusions:
- MGC may play a role in granuloma formation through IL-1 production.
- Loss of phagocytic and tumoricidal functions in MGC suggests alternative roles in immunity.