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AM-3K, a novel monoclonal antibody specific for tissue macrophages and its application to pathological investigation
L Zeng1, M Takeya, K Takahashi
1Second Department of Pathology, Kumamoto University School of Medicine, Japan.
Abstract:
An anti-human macrophage monoclonal antibody, AM-3K, was produced using human alveolar macrophages as antigen. The molecular weights of the antigen recognized by AM-3K were 120 and 70 kD. Immunohistochemically, AM-3K reacted intensely with most macrophages in lymphoreticular organs and in many other organs and tissues. In the spleen, AM-3K reacted with red pulp macrophages, some white pulp macrophages, and tingible body macrophages in lymphoid follicles. In the lymph nodes, many macrophages distributed in the outer cortex, paracortical area, medulla, capsule, or within lymphoid follicles showed an intense reaction for AM-3K. Kupffer cells of the liver, macrophages in the connective tissues, and interstitial macrophages of the kidneys, pancreas, testis, and many other organs were also strongly labelled. AM-3K also reacted with macrophages in many pathological conditions. This antibody, however, did not react with dendritic cell populations, such as epidermal Langerhans cells, interdigitating cells in the paracortex of the lymph nodes, and follicular dendritic cells within the lymphoid follicles, nor with cells other than macrophages, including epithelial cells, vascular endothelial cells, lymphocytes, and granulocytes. Reaction products for AM-3K were found on the cytoplasmic membrane of macrophages by immunoelectron microscopy. In both cryostat sections and formalin-fixed paraffin sections, this monoclonal antibody recognized the antigen present on the cell surface membrane of tissue macrophages, but not monocytes or dendritic cells.
Insights
A new monoclonal antibody, AM-3K, specifically targets human macrophages, aiding in their identification across various tissues and pathological conditions. This antibody distinguishes macrophages from dendritic cells and monocytes.
Area of Science:
- Immunology
- Cell Biology
- Histopathology
Background:
- Macrophages are critical immune cells involved in tissue homeostasis and disease.
- Developing specific antibodies for macrophage identification is essential for research and diagnostics.
- Previous methods lacked specificity for distinguishing macrophages from other cell types.
Purpose of the Study:
- To produce and characterize a novel monoclonal antibody, AM-3K, against human macrophages.
- To evaluate the reactivity and specificity of AM-3K in various human tissues and cell types.
- To investigate the utility of AM-3K in identifying macrophages in both normal and pathological conditions.
Main Methods:
- Production of monoclonal antibody AM-3K using human alveolar macrophages as antigen.
- Immunohistochemical staining of various human organs and tissues.
- Immunoelectron microscopy to determine the localization of the recognized antigen.
- Testing reactivity against dendritic cells, monocytes, lymphocytes, and granulocytes.
Main Results:
- AM-3K recognizes antigens of 120 and 70 kD on human macrophages.
- Intense staining of macrophages observed in lymphoreticular organs, spleen, lymph nodes, liver, kidneys, pancreas, and testes.
- AM-3K specifically labels tissue macrophages, excluding monocytes and dendritic cells (Langerhans cells, interdigitating cells, follicular dendritic cells).
- Antibody reactivity confirmed in macrophages within various pathological conditions.
- Immunoelectron microscopy showed AM-3K binding to the cytoplasmic membrane of macrophages.
Conclusions:
- The monoclonal antibody AM-3K is a highly specific marker for human tissue macrophages.
- AM-3K can differentiate macrophages from monocytes and dendritic cells.
- This antibody is valuable for studying macrophage distribution and function in normal and diseased states.