Potentiation of myeloid colony-formation in bone marrow of intact and neonatally thymectomized mice by the thymic hormone THF-gamma 2.
The effect of the thymic hormone THF-gamma 2 on committed stem cells of bone marrow (BM) origin was determined using the myeloid progenitor cell clonal assay. Preincubation of normal BM cells with THF-gamma 2 for 1 hour or 18 hours caused a 2- to 6-fold increase in the number of myeloid colonies in the presence of suboptimal concentrations of colony-stimulating factor (CSF). The optimal dose of THF-gamma 2 causing this enhancement was in the range of 25 to 100 ng/mL. THF-gamma 2 was not able to replace CSF as an inducer in these experiments. THF-gamma 2 neither induced IL-6 activity upon 24-hour incubation with bone marrow cells nor enhanced LPS-induced IL-6 secretion by bone marrow cells in vitro. Neonatal thymectomy (NTx) of Balb/c mice caused a decrease in myeloid progenitors, which was repaired by serial injections of THF-gamma 2. The repair of the stem cell compartment in the bone marrow correlated with an increased percentage of Thy1+ cells in the spleen of THF-gamma 2-treated NTx mice. These findings indicate that THF-gamma 2 is able to regulate committed stem cell functions in the bone marrow of immune-deprived NTx and of normal mice.
Pecht
M
M
Department of Organic Chemistry, Weizmann Institute of Science, Rehovot, Israel.
Lourie
S
S
Burstein
Y
Y
Zipori
D
D
Trainin
N
N
D000818:Animals; D000831:Animals, Newborn / Q000502:physiology*; D001853:Bone Marrow / Q000187:drug effects / Q000502:physiology; D001854:Bone Marrow Cells; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D003115:Colony-Stimulating Factors / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D006410:Hematopoiesis / Q000187:drug effects / Q000502:physiology*; D015850:Interleukin-6 / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D009842:Oligopeptides / Q000494:pharmacology*; D013154:Spleen / Q000166:cytology / Q000502:physiology; D013934:Thymectomy; D013951:Thymus Hormones / Q000494:pharmacology*; D013997:Time Factors
D003115:Colony-Stimulating Factors; D015850:Interleukin-6; D009842:Oligopeptides; D013951:Thymus Hormones; C064563:thymic humoral factor gamma 2