ND indicates not done; tertiary transfers were not attempted if secondary hosts were not repopulated.

BM cells were isolated from primary and secondary hosts at least 7 months after transplantation for transfer into secondary and tertiary hosts, respectively. In each case, 5 × 10⁶ BM cells were injected and the same methods and criteria were used to identify repopulated mice as for primary hosts (“Materials and methods”). Data are extended and modified from Muller-Sieburg et al.¹³