Abstract
Intrathymic injection of the Abelson murine leukemia virus (A-MuLV) results in transformation
of immature T and B lymphoid cells. In this report we demonstrate that the concentration
of A-MuLV injected into murine thymi influences the selection of the transformation target.
Thus, concentrated A-MuLV gives rise to Thy-1+ B220- thymomas. In contrast, dilute virus
induces B220+ thymomas that also express low levels of Thy- 1 (Thy-1lo), a phenotype that is
similar to marrow-derived progenitor B-lymphoid cells (pro-B cells) that are highly susceptible
to A-MuLV transformation invitro. However, rare B220+ lymphoid cells isolated from
normal adult thymi were not transformed by A-MuLV invitro, while B220+ cells isolated
from bone marrow were highly susceptible to transformation by A-MuLV. The Thy-1lo
B220+population in the primary thymomas had not rearranged TCR