B. Garciahernandez et al., MURINE HEMATOPOIETIC RECONSTITUTION AFTER TAGGING AND SELECTION OF RETROVIRALLY TRANSDUCED BONE-MARROW CELLS, Proceedings of the National Academy of Sciences of the United Statesof America, 94(24), 1997, pp. 13239-13244
A major problem facing the effective treatment of patients with cancer
is how to get the specific antitumor agent into every tumor cell. In
this report we describe the use of a strategy that, by using retrovira
l vectors encoding a truncated human CD5 cDNA, allows the selection of
only the infected cells, and we show the ability to obtain, before bo
ne marrow transplantation, a population of 5-fluouraci-treated murine
bone marrow cells that are 100% marked. This marked population of bone
marrow cells is able to reconstitute the hematopoietic system in leth
ally irradiated mice, indicating that the surface marker lacks deleter
ious effects on the functionality of bone marrow cells, No gross abnor
malities in hematopoiesis were detected in mice repopulated with CD5-e
xpressing cells. Nevertheless, a significant proportion of the hematop
oietic cells no longer expresses the surface marker CD5 in the 9-month
-old recipient mice. This transcriptional inactivity of the proviral l
ong terminal repeat (LTR) was accompanied by de novo methylation of th
e proviral sequences. Our results show that the use of the CD5 as a re
trovirally encoded marker enables the rapid, efficient, and nontoxic s
election in vitro of infected primary cells, which can entirely recons
titute the hematopoietic system in mice. These results should now grea
tly enhance the power of studies aimed at addressing questions such as
generation of cancer-negative hematopoiesis.