Morphology of LTBMCs obtained from 7-week-old mice. Dexter's cultures of TN-C–deficient mice (a) and of control mice (b) were photographed under an inverted microscope at week 25 after culturing. Large hematopoietic foci were seen in the control culture. Whitlock-Witte's cultures of TN-C–deficient mice (c) and of control mice (d) were photographed at week 15. Bar, 100 μm. Significant decrease in hematopoietic activity was observed in LTBMCs of TN-C–deficient mutant mice.