[The effects of cytokines mediated ex vivo expansion on the cell adhesion molecule expression of cord blood hematopoietic stem and progenitor cells].

OBJECTIVE

To compare the expression of cell adhesion molecules (CAMs) among VLA-4 (CD49 d), VLA-5 (CD49e), LFA-1 (CD11a), L-selectin (CD62L), and PECAM-1 (CD31) which are more related to the homing of hematopoietic stem and progenitor cells (HSPC) on the ex vivo expanded CD34+ subset with that of fresh isolated AC133+ cells.

METHODS

AC133+ cells selected from fresh cord blood (CB) samples were cultured in QBSF-60 serum-free media in the presence of Flt-3 ligand + SCF + TPO (FST), with initial addition of IL-3 for up to 2 week. Expansion potential and the expression of above CAMs were evaluated at day 0, day 7, day 10 and day 14.

RESULTS

(1) Simultaneously numerical expansion of various HSPC was constantly observed during the culture, and the fold expansion of AC133+ cells and CD34+ cells on day 14 were 33.50 and 64.56 respectively; (2) The number of CD34+ subsets expressing the above adhesions were all increased at different degrees (from 20 fold to 160 fold). (3) The expressions of CD11a, CD49d, and CD49e on ex vivo expanded CD34+ cells were increased as compared to their baseline levels, but the percentage of CD62L+ and CD31+ subpopulations in CD34+ cells were decreased.

CONCLUSIONS

Our short-term culture system can not merely support the simultaneous expansion of CB derived AC133+ cells, but the expanded hematopoietic progenitors may well sustained the expression of homing-related adhesion molecules.