Production of thymic cells by mouse spleen and bone marrow.
Karyotype difference between the AKR/TIALD strain (T1) that bears 2  metacentric markers, and the AKR strain (no marker) was used to follow the thymic repopulation of lethally irradiated (AKR X T1) F1 hybrids restored by AKR bone marrow (BM) or spleen cells. Eleven days following radiation exposure, 40-50% of the thymic cells were BM-derived in the mice restored with BM cells whereas spleen-derived cells remained below 10% in those restored with spleen cells. The thymic repopulation by spleen-derived elements was enhanced either by injecting a larger munber of spleen cells or by adding thymic cells to the spleen inoculum; however in both cases the appearance of the spleen-derived karyotypes still required a delay of about 11 days. The thymic cells could either recruit thymic precursor cells or trigger their multiplication. On the opposite, it has not been possible to demonstrate a favorable effect of the injected thymic cells on the repopulation of the thymus by BM-derived elements.
D000818:Animals; D002454:Cell Differentiation; D002455:Cell Division; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D007621:Karyotyping; D008297:Male; D051379:Mice; D013154:Spleen / Q000166:cytology*; D013950:Thymus Gland / Q000166:cytology* / Q000528:radiation effects; D014965:X-Rays