Age-dependent changes in the proportion of macrophages in primary thymus non-lymphoid cell cultures.
Primary murine thymus cell cultures consist of thymus epithelial cells, macrophages and interdigitating dendritic cells. Results of the present study indicated that the proportion of macrophage-like cells in cultures was directly related to the age of the thymus donors through 7 weeks of age. We standardized procedures to compare primary thymic cultures derived from mice, 1 day to 115 days of age. Cultures were grown 6 to 8 days and then tested for nonspecific esterase, acid phosphatase, phagocytosis of latex beads, Fc receptors, and MAC-1 staining. Less than 10% macrophage-like cells were identified in cultures from mice 1 to 3 days-old, but the proportion increased to 50% macrophage-like cells in cultures from 7 week-old mice. Thereafter the proportion plateaued although there was considerable variation among older mice. Further studies showed that the proportions of macrophage-like cells was not affected by the number of cells initially seeded into culture, nor by the amount of serum added to the culture medium. These data suggest that macrophage/interdigitating cell precursors immigrate into the thymus for 4 to 6 weeks after birth and support the hypothesis that these precursors may be influenced to differentiate into thymus macrophages or interdigitating cells by the thymic microenvironment.
Department of Cell Biology, Ohio State University, Columbus 43210.
K H
KH
Jones
E J
EJ
Stutz
L P
LP
Sirinek
D000367:Age Factors; D000818:Animals; D002478:Cells, Cultured; D005260:Female; D007150:Immunohistochemistry; D016177:Macrophage-1 Antigen / Q000032:analysis; D008264:Macrophages / Q000166:cytology*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D011961:Receptors, Fc / Q000032:analysis; D013950:Thymus Gland / Q000166:cytology*
D016177:Macrophage-1 Antigen; D011961:Receptors, Fc