Lymphoreticular cells in human brain tumours and in normal brain

Area of Science:

• Neuroimmunology
• Oncology
• Cell Biology

Background:

• The presence and role of immune cells within the human brain, particularly in the context of tumors, remain areas of active investigation.
• Understanding the composition of the cellular infiltrate in brain tumors is crucial for developing targeted immunotherapies.

Purpose of the Study:

• To investigate the presence and characteristics of lymphoreticular cells in normal human brain tissue and malignant brain tumors.
• To identify specific immune cell populations, including lymphocytes and macrophages, and their distribution within these tissues.
• To explore the potential immunological functions of these cells in the brain microenvironment.

Main Methods:

• Preparation of cell suspensions from human normal brain (cerebral cortex, cerebellum) and malignant brain tumors using mechanical disaggregation and collagenase digestion.
• Application of various rosetting assays to identify and quantify lymphoreticular cells, including T and B lymphocytes and their subsets.
• Morphological assessment and characterization of phagocytic cells (macrophages and microglial cells) using sudan black staining and receptor analysis (Fc(IgG), C3).

Main Results:

• Lymphoreticular cells, including T and B lymphocytes and their subsets, were detected in 5 out of 14 glioma tumor suspensions, constituting less than 15% of the cell population.
• Macrophages, identified by morphology and rosetting ability (up to 75%), represented 20-60% of cells in tumor suspensions.
• Lymphocytes were notably absent in cancer-free (normal) brain tissue. Macrophages and microglial cells were present in normal brain similarly to tumor tissue, but exhibited lower rosetting avidity.

Conclusions:

• The findings suggest that lymphocytes are primarily associated with malignant brain tumors, while macrophages and microglial cells are resident components of the normal brain.
• The presence of phagocytic cells expressing Fc(IgG) and C3 receptors in both normal and tumor brain tissue indicates a potential innate immunological defense mechanism.
• Further research is warranted to elucidate the specific roles of these immune cells in brain tumor pathogenesis and potential therapeutic strategies.