ISSN:
1573-4919
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
Notes:
Summary Functionally distinct subpopulations of macrophages at various stages of differentiation can be separated by fractionation of murine peritoneal cells according to size, since the maturation of monocytes into macrophages is associated with cell enlargement. For immunostimulatory functions which can be served by macrophage-derived factors, normal macrophages of all sizes will function very well. However, in the antigen-specific T cell proliferative response which requires the presentation of antigen on the surface of macrophages bearing determinants (Ia) specified by the I-region of the major histocompatibility complex, only small, and hence relatively immature, macrophages will stimulate. This antigen-presenting activity is predictably sensitive to treatment with antisera specific for Ia. Intraperitoneal administration of the adjuvant, Corynebacterium parvum, induces the appearance of cytostatic and cytolytic activity against tumor cells. This activity is associated with the largest macrophages which are separable from the small, immunostimulatory macrophages. Thus the maturation of monocytes can be envisaged as following a linear sequence from the Ia+ antigen-presenting cells to the cytocidal activated macrophages. An alternative approach to the problem of macrophage heterogeneity is the cultivation of macrophages from bone marrow precursors in vitro. Antigen-presenting activity develops during the exponential phase of growth to varying degrees depending on the source of the colony stimulating factor used in the bone marrow cultures and on the antigen used for immune stimulation. Although culture-grown macrophages are as active as normal splenic or peritoneal macrophages at presenting large antigens, they are clearly deficient at presenting small antigens. Cell size fractionation of exponentially growing bone marrow cultures has revealed that the antigen-presenting cells are small macrophages, but their position in the cell cycle and their developmental relationship to macrophages in vivo have not been elucidated.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00215304
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