Self‐renewal of factor‐dependent hemopoietic progenitor cell‐lines derived from long‐term bone marrow cultures demonstrates significant mouse strain genotypic variation

Abstract

Long‐term bone marrow cultures established from C57Ks/J mice have been shown to spontaneously release endogenous ecotropic RNA type‐C virus (retrovirus). C57Ks/J marrow cultures produced granulocyte‐macrophage progenitor cells (GM‐CFUc) and immature and mature granulocytes for over 45 weeks. In contrast, NIH Swiss mouse marrow cultures failed to release detectable ecotropic virus and generated GM‐CFUc and granulocytes for 25–35 weeks and established WEHI‐3 conditioned medium (CM) dependent cell lines in vitro and did not establish permanent cell lines. To determine whether viral and/or cellular genes regulated the longevity of C57Ks/J marrow cultures, groups of cultures were established from the marrow of (NIH‐Swiss × C57Ks/J) F1 hybrid, F2 hybrid, and (NIH Swiss × C57Ks/J) X NIH Swiss backcross generations. Release of endogenous ecotropic virus was measured weekly in each culture as was the duration of production of immature granulocytic cells and GM‐CFUc over a 58‐week period. The results demonstrated a complex pattern of inheritance of longevity of long‐term in vitro hemopoiesis. Increased longevity did not absolutely correlate with detectable replication of the C57Ks/J N‐tropic virus.