Hemopoietic cells perform many vital functions in the maintenance of homeostasis and integrity of the body. These functions include, among others, the transport of oxygen by erythrocytes, and the initiation of blood clotting by thrombocytes at sites of injury. Furthermore, hemopoietic cells are the primary effector cells in the defense against micro-organisms and tumor cells. This defense is mainly carried out by two different cell types: lymphocytes and phagocytes. The distinction between these cell types is, among other things, based upon the different mechanisms that lymphocytes and phagocytes use to recognize foreign material. Lymphocytes recognize invading substances by highly specific antigen receptor molecules which are different and specific for each antigen. Mononuclear and polymorphonuclear phagocytes, on the other hand, discern their foreign targets by receptor molecules with much broader specificity, such as lectin-like receptors recognizing carbohydrate moieties. From an evolutionary point of view, phagocytes are the most 'ancient' cells in host defense. All multicellular animals contain amoeboid phagocytic cells; in some invertebrates such cells are even the only blood cells present. In general, increasing evolutionary ancientry coincides with increasing phenotypical diversity. The heterogeneity among phagocytes, and especially among the mammalian mononuclear phagocytes, clearly demonstrates the validity of this general rule. In this thesis, an analysis is presented of the phenotypical differentiation of murine mononuclear phagocytes, i.e. macrophages and their precursors. The term 'differentiation' in this context includes both the process of maturation and of diversification. It should be realized, however, that the term 'differentiation' is also generally used as equivalent to maturation only. In the next section an introductory overview is given of our current knowledge of macrophage differentiation. The literature cited in this overview primarily deals with studies performed with mice as experimental animals, since the subsequent chapters describe results of experimental studies using murine cells.

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Erasmus University Rotterdam
O. Vos
hdl.handle.net/1765/50910
Erasmus MC: University Medical Center Rotterdam

Leenen, P. (1989, December 22). Phenotypical analysis of murine macrophage differentiation. Retrieved from http://hdl.handle.net/1765/50910