Cl. Li et al., PURIFIED MURINE LONG-TERM IN-VIVO HEMATOPOIETIC REPOPULATING CELLS ARE NOT PROTHYMOCYTES, Experimental hematology, 23(1), 1995, pp. 21-25
Analysis of kinetics of thymic repopulation by Rh123(low), Lin(-), Ly6
A/E(+), c-kit(+) (RH123(low)) cells, highly enriched for long-term in
vivo hematopoietic repopulating cells, reveals that this population is
deficient in thymic repopulation at week 3 after intravenous transpla
ntation when compared to normal bone marrow cells. This suggests that
the marrow prothymocytes have been depleted from this population, and
analysis of thymic repopulation at week 3 can therefore be used to dif
ferentiate prothymocytes and their precursors. Using this short-term a
ssay, the Rh123(high) Lin(-), Ly6A/E(+), c-kit(+) (Rh123(high)) popula
tion has been found to be relatively more efficient at early thymic re
population, suggesting that this population contains the prothymocytes
. In addition, the differentiation potential. and reconstitution behav
ior of the Rh123(high) population observed after intravenous and intra
thymic transfer strongly indicates that this population is at the tran
sitional stage between the marrow primitive pluripotential and thymic
more mature lymphoid restricted stem cells. We propose that the thymic
repopulating ability of the Rh123(low) population is through generati
on of the more mature Rh123(high) progeny, presumably in the marrow.