Thymodepressin inhibits migration of CD34+ cells from bone marrow in normal and granulocyte CSF-stimulated hemopoiesis.

We studied the effect of thymodepressin on migration and adhesion of mouse hemopoietic CD34+ cells under normal conditions and under the effect of granulocytic CSF. It was found that the peptide reduced the absolute number of CD34+ hemopoietic cells in the peripheral blood, increased the percent of cells bound to fibronectin and expressing receptor for integrin beta1 (CD29+) in the bone marrow of mice under normal conditions and after stimulation with granulocytic CSF, and reduced the relative number of cells carrying CXCR4 receptor for stromal factor-1 (CD184+) in the bone marrow (CD34+CD184+) and blood (CD184+) of mice stimulated with granulocytic CSF. The results suggest that thymodepressin can inhibit migration of CD34+ cells from bone marrow into peripheral blood under conditions of normal and granulocytic CSF-stimulated hemopoiesis.