In vitro proliferation and differentiation of hemic precursor cells from marrow and blood of naturally chimeric marmosets.

Abstract

AbstractMarmosets are unique in that they are “always” blood cell chimeras. When the nucleated cells from the bone marrow and from the peripheral blood of marmosets were incubated in the appropriate culture fluid they were shown capable of extensive proliferation in vitro. Two patterns of cellular proliferation, adherent and nonadherent, occurred in the same culture vessel. Repeated passage of nonadherent cells in RPMI 1640 medium supplemented with calf serum resulted in relatively long‐term fluid bulk cultures showing myelocytic differentiation and megakaryocytic maturation. As myelocytic maturation became the predominant feature of cultures mitoses of the precursors diminished. About half of 41 marrow‐derived cultures underwent extensive proliferation lasting about two months, as evidenced by an increasing cellularity and the presence of dividing cells. Such active growth occurred in one culture for over 120 days. The natural blood‐cell chimerism of marmosets was demonstrated in vitro by cytogenetic analyses of metaphases from four relatively long term marrow cultures. The ratios of male and female cells remained either relatively stable or changed slowly with time in culture. Cells having both diploid and polyploid number of chromosomes were identified male or female, suggesting chimerism in myelocytic and megakaryocytic series. Marmoset lymph node and spleen cells proliferated as lymphoid cultures for various lengths of time up to five weeks but these cells did not differentiate into hemic cell lines. Attempts to culture human and rodent hemic tissue by the procedure used on marmoset tissue were unsuccessful.