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Distribution of the CD68 macrophage/myeloid associated antigen
K A Pulford1, A Sipos, J L Cordell
1Nuffield Department of Pathology, John Radcliffe Hospital, Oxford, UK.
Insights
CD68 antibodies are useful macrophage markers but can also stain other cells. Researchers found subtle differences suggesting CD68 antigen heterogeneity, cautioning against sole reliance for diagnosing unknown tumors.
Area of Science:
- Immunology
- Cell Biology
- Histochemistry
Background:
- The CD68 antigen is a widely used pan-macrophage marker.
- Its utility in distinguishing myeloid cells necessitates a thorough understanding of its expression patterns.
Purpose of the Study:
- To investigate the distribution and potential heterogeneity of the CD68 antigen.
- To evaluate the specificity of different CD68 monoclonal antibodies across various human cell types.
Main Methods:
- Utilized alkaline phosphatase anti-alkaline phosphatase (APAAP) staining.
- Employed Western blotting techniques.
- Examined human blood, tissue, and cell lines.
Main Results:
- All CD68 antibodies stained monocytes and macrophages.
- Some antibodies showed cross-reactivity with neutrophils, basophils, and lymphocytes.
- Varied staining patterns were observed on non-haemopoietic cells, suggesting antigen heterogeneity potentially due to glycosylation differences.
Conclusions:
- CD68 antibodies are valuable for identifying macrophage and myeloid lineage cells.
- The observed cross-reactivity and heterogeneous staining patterns necessitate caution when using CD68 for diagnosing tumors of unknown origin.
Abstract:
The distribution of the pan-macrophage CD68 antigen, recognized by six different monoclonal antibodies, was examined in human blood, tissue, and cell lines using APAAP staining and Western blotting. All antibodies stained monocytes and macrophages, but labelling of neutrophils, basophils, and lymphocytes was seen with some of the reagents. In addition, the CD68 antibodies demonstrated a variety of staining patterns on some non-haemopoietic cells. The subtle differences between the reactions of the different antibodies suggested that the CD68 antigen may be heterogeneous, possibly due to differences in glycosylation. While CD68 antibodies are very useful markers of the macrophage/myeloid series, the presence of small amounts of the antigen on some lymphoid and non-haemopoietic cells means that care should be taken when using them for the diagnosis of tumours of unknown origin.
