Variable expression of Qa-m7, Qa-m8, and Qa-m9 antigenic determinants on primitive hemopoietic precursor cells
✍ Scribed by R. A. Harris; M. S. Sandrin; V. R. Sutton; P. M. Hogarth; I. F. C. McKenzie; D. G. Penington
- Publisher
- John Wiley and Sons
- Year
- 1985
- Tongue
- English
- Weight
- 866 KB
- Volume
- 123
- Category
- Article
- ISSN
- 0021-9541
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✦ Synopsis
Using monoclonal antibodies, we have analysed the distribution of three recently described Qa antigenic determinants (Qa-m7, Qa-m8 and Qa-m9) on murine clonable hemopoietic progenitor cells and spleen colony-forming units (CFU-S). Cytotoxicity experiments showed that Qa-m7 was expressed on almost all the progenitor cells (colony-forming cells, CFC) of megakaryocytes (MEG-CFC), erythroid cells (E-CFC), B lymphocytes (BL-CFC), and mixed colonies (MIX-CFC) as well as day 13 CFU-S, and a major proportion of granulocyte-macrophage colony-forming cells (GM-CFC) and day 8 CFU-S. Experiments using four sources of granulocyte-macrophage colony-stimulating activity suggested differential expression of Qa-m7 on subpopulations of GM-CFC, those preferentially forming macrophage colonies having lowest Qa-m7 antigen density. Immune rosetting techniques demonstrated the selective expression of Qa-m8 on approximately 50% of MEG-CFC, MIX-CFC and day 13 CFU-S, a pattern similar to that of Qa-m2. In contrast, Qa-m9 was not detected on any of the primitive hemopoietic precursors assayed. The results demonstrate the complexity of the Qa antigenic system, and suggest a possible role for these antigens in hemopoietic differentiation.
Monoclonal antibodies have proven to be valuable reagents in analyzing the surface antigenic structure of many cells, including hemopoietic cells. They have the potential of enabling the purification and characterization of primitive cells such as colony-forming cells (CFC) and spleen colony-forming units (CFU-S) which are present in very low frequency in hemopoietic tissues. However, to date, few studies have reported antigen expression restricted to primitive cells or to a particular