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Human peripheral blood mononuclear cells (PBM's) cultured in serum free medium (II): Lymphocyte-macrophage
Abstract:
Morphological descriptions of the attachments between lymphocytes and macrophages are made in serum free cultures. Dynamic morphological processes related to these attachments are explored in live cells using an inverted microscope and the phase technique. The May Grunwald-Giemsa stain and scanning and transmission electron microscopy are also described for the same population of cells. Immunoglobulins were detected in the cells by the immunoflourescence technique. Following lymphocyte-macrophage attachments, the macrophages shrink and round up and subsequently, their cytoplasm becomes laden with immunoglobulin. The membrance surface of interacting macrophages gradually changes from the ruffled appearance characteristic of a monocyte to a blebbed structure. The blebs seem to be related to an exocytotic process, which is most probably immunoglobulin secretion.
Insights
Lymphocyte-macrophage attachments trigger dynamic morphological changes in macrophages, leading to immunoglobulin accumulation and secretion. This study reveals key cellular interactions in immune responses.
Area of Science:
- Immunology
- Cell Biology
- Microscopy
Background:
- Lymphocyte-macrophage interactions are crucial for immune responses.
- The dynamic morphological changes during these interactions are not fully understood.
Purpose of the Study:
- To describe the morphological changes of macrophages during attachment with lymphocytes.
- To investigate the dynamic processes involved in lymphocyte-macrophage attachments.
- To explore the role of immunoglobulins in these cellular interactions.
Main Methods:
- Serum-free cell cultures.
- Live-cell imaging using inverted microscopy and phase contrast.
- May Grunwald-Giemsa staining.
- Scanning and transmission electron microscopy (SEM/TEM).
- Immunofluorescence technique for immunoglobulin detection.
Main Results:
- Macrophage shrinkage and rounding upon lymphocyte attachment.
- Intracellular immunoglobulin accumulation within macrophages.
- Transformation of macrophage membrane from ruffled to blebbed structures.
- Bleb formation suggests an exocytotic process, likely immunoglobulin secretion.
Conclusions:
- Lymphocyte-macrophage attachment induces significant, dynamic morphological alterations in macrophages.
- Macrophages exhibit immunoglobulin uptake and subsequent secretion following interaction.
- The observed blebbing is indicative of an active exocytotic mechanism for immunoglobulin release.