[Observation on the biological behavior of human umbilical cord blood adherent cells].

To study the possibility of separation and culture of human umbilical cord blood adherent cell (HUCBAC), the umbilical cord blood CD34(+) cells were cultured in Dexter system in order to evaluate and observe the biological behavior of adherent cells in vitro. The results showed that all cells were cultured with Dexter system. By day 9-14 (at a median of 11.2 days), adherent cell colonies formed and reached their maximum at 15-22 days (mean 19.6 days), by day 28, all adherent cells spread over the bottom of Petri dish. By means of light microscopy, these cells were found to differentiate into three kinds of cells in culture of 28 days: fibroblast-liked cell, macrophage liked cell and small-round cells. The ratio of these three kinds of cells was 56.8%, 38%, 5.5% respectively. Cytochemistry assay revealed that the positive rate reached 100% in NSE stain and PAS stain; the adherent cell by ALP stain were shown 35% positive, but in POX stain the result was negative. Immunohistochemistry stain revealed that the positive rate of cord adherent cells for CD106, CD29, CD44, CD45, CD50, Fn, Ln, collagen IV etc reached 96%, 93%, 98%, 68%, 72%, 92%, 74%, 83% respectively. It is concluded there are hematopoietic adherent precursors in cord blood CD34(+) cells and the HUCBAC shows some biological behavior of hematopoietic stromal cells.