Umbilical Cord Blood Cultures Research Articles

Effects of recombinant human interleukin-3 on CD34-enriched normal hematopoietic progenitors and on myeloblastic leukemia cells

Induction of proliferation and differentiation in response to recombinant human interleukin-3 (hIL-3) was studied in liquid and semisolid cultures of umbilical cord blood and bone marrow cells that were fractionated by “panning” with anti-My10 antibody according to expression of CD34 antigen. Cells from enriched fractions (70% to 90% CD34+) were found to proliferate strongly in response to hIL-3. Phenotypic analysis and morphologic characterization of the proliferating cells demonstrated a rapid decrease in CD34+ cells and an exponential increase in the number of cells belonging to the neutrophilic, eosinophilic, monocyte/macrophage, and thrombocytic lineages. When combined with recombinant human erythropoietin, burst colonies and cells expressing glycophorin-A were detected, thereby demonstrating the effects of hIL-3 on erythroid progenitors. Further, the development of mixed-erythroid colonies indicated that multipotential cells within CD34-enriched fractions responded to hIL-3. In addition, we examined the effect of hIL-3 on the proliferation of primary acute myeloblastic leukemia cells in liquid culture. We found that hIL-3 was able to induce cell proliferation in a proportion of the cases tested. Heterogeneity of the responses to hIL-3 was in part related to French-American-British classification but could not be correlated with CD34 antigen expression by the leukemic cells. These results indicate that, although the effects of hIL-3 on proliferation and differentiation of cells obtained from normal hematopoietic specimens were primarily borne by CD34+ cells, expression of the CD34 molecule per se is an insufficient condition to determine a growth response to this lymphokine.

Effects of Recombinant Human Interleukin-3 on CD34-Enriched Normal Hematopoietic Progenitors and on Myeloblastic Leukemia Cells

Induction of proliferation and differentiation in response to recombinant human interleukin-3 (hIL-3) was studied in liquid and semisolid cultures of umbilical cord blood and bone marrow cells that were fractionated by "panning" with anti-My10 antibody according to expression of CD34 antigen. Cells from enriched fractions (70% to 90% CD34+) were found to proliferate strongly in response to hIL-3. Phenotypic analysis and morphologic characterization of the proliferating cells demonstrated a rapid decrease in CD34+ cells and an exponential increase in the number of cells belonging to the neutrophilic, eosinophilic, monocyte/macrophage, and thrombocytic lineages. When combined with recombinant human erythropoietin, burst colonies and cells expressing glycophorin-A were detected, thereby demonstrating the effects of hIL-3 on erythroid progenitors. Further, the development of mixed-erythroid colonies indicated that multipotential cells within CD34-enriched fractions responded to hIL-3. In addition, we examined the effect of hIL-3 on the proliferation of primary acute myeloblastic leukemia cells in liquid culture. We found that hIL-3 was able to induce cell proliferation in a proportion of the cases tested. Heterogeneity of the responses to hIL-3 was in part related to French-American-British classification but could not be correlated with CD34 antigen expression by the leukemic cells. These results indicate that, although the effects of hIL-3 on proliferation and differentiation of cells obtained from normal hematopoietic specimens were primarily borne by CD34+ cells, expression of the CD34 molecule per se is an insufficient condition to determine a growth response to this lymphokine.

Syncytium formation in aged umbilical cord blood macrophages. Attempts to demonstrate an infectious etiology.

About 50% of cultures of mononuclear cells from human umbilical cord blood kept for more than 6 weeks in tissue culture reveal syncytium formation of adherent cells involving varying percentages of cells. Syncytium formation usually occurs focally producing plaques of multinucleated giant cells followed by cell degeneration. Occasionally, plaques of giant cell formation of adherent cells were also noted in macrophage cultures obtained from healthy adult blood donors. Attempts to transfer cytopathogenic changes to other human epithelial and fibroblastic cells in tissue culture were unsuccessful. In three instances, however, fibroblast-like cells started to grow spontaneously in umbilical cord blood cultures revealing syncytium formation and were subcultured once or twice. Six to eight weeks after their appearance, these cells too degenerated spontaneously also showing syncytium formation. Nuclei of the fused cells contained prominent nucleolus-like structures. Electron microscopy failed to demonstrate viral particles within these intranuclear inclusions. Occasionally, however, virus-like particles resembling in size and some structural features that of herpesviruses, were found in degenerating cells. Nucleic acid hybridizations performed with cellular DNA derived from such cultures and 32P-labelled DNA of herpesvirus saimiri and human cytomegalovirus failed to reveal any homologies. In a series of human sera tested for reactivity against fused cells in an indirect immuno-fluorescence test, two reacted specifically at low titer against the nucleolus-like structures of syncytial cells and some additional mononuclear cells.

Synthesis of fetal and adult hemoglobins in culture by human umbilical cord blood erythropoietic precursors.

We cultured human umbilical cord blood and adult peripheral blood erythropoietic precursors in methylcellulose clonal assay and measured the synthetic rates of HbA, A2, and F. Hb was labeled with 14C-amino acid in culture and separated by slab-gel isoelectric focusing and quantitated by autoradiography. While the mean percentage of HbF synthesized by adult cells was only 20.1%, that of umbilical cord blood cells was 53.9%, which corresponds closely to the biosynthetic capabilities of umbilical cord blood reticulocytes. Variations in the erythropoietin concentrations did not influence the percentage of HbF. Erythropoietic cell cultures of human umbilical cord blood may provide an important means for studying the molecular mechanisms controlling physiological Hb switching in the perinatal period.

A CONTROLLED STUDY OF THE INFLUENCE ON THE NEWBORN OF PROLONGED PREMATURE RUPTURE OF THE AMNIOTIC MEMBRANES AND/OR INFECTION IN THE MOTHER

A CONTROLLED STUDY OF THE INFLUENCE ON THE NEWBORN OF PROLONGED PREMATURE RUPTURE OF THE AMNIOTIC MEMBRANES AND/OR INFECTION IN THE MOTHER