Culture of endothelial cells isolated from maternal blood using anti-CD105 and CD133

Objectives: We hypothesized that fetal cells in maternal blood that do not respond to hematopoietic culture conditions represent endothelial cells. We investigated whether endothelial progenitor cells of fetal origin may be selected from maternal blood on the basis of their expression of CD133 or CD105 and expanded in culture. Methods: Peripheral blood mononuclear cells from 16 pregnant women (gestational age: 11 to 24 weeks) were labeled with magnetic beads coupled to anti-CD133 or anti-CD105. Selection of labeled cells was performed using MACS. Resulting CD133+, CD105+, and CD133-/CD105- cell fractions were placed in culture in conditions favoring endothelial cells for 7 days (positive fractions) to 30 days (depleted fractions). Cells from women carrying male fetuses were analyzed by conventional PCR (SRY primers) for detection of male cells. Results: Expansion of cells isolated from all subjects occurred in each of the cell fractions. No PCR products consistent with the presence of male cells were detected in women carrying male fetuses. Conclusion: CD133+ and CD105+ cells isolated from maternal blood can be expanded in vitro under endothelial conditions. These cells appear to be of maternal, rather than fetal, origin.