Stem Cells Research Today is a free monthly online journal that collates and summarizes the latest research about Stem Cells, including details on research, transplants, therapy, benefits.

Selection of stem cells by using antibodies that target different CD34 epitopes yields different patterns of T-cell differentiation.

Otto M, Chen X, Martin WJ, Leung W, Knowles J, Holladay M, Houston J, Handgretinger R, Barfield RC

Division of Stem Cell Transplantation, Department of Hematology/Oncology, St. Jude Children's Research Hospital, 332N Lauderdale Street, Memphis, Tennessee 38105-2794, USA.

The objective of this study was to compare the patterns of T-cell differentiation from CD34(+) human stem cells selected with different classes of antibody targeting the CD34 molecule. We compared signal-joint T-cell receptor excision circle (sjTREC) production in thymocytes selected with different classes of anti-CD34 antibody. Based on these results, we studied immune reconstitution in nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice using human stem cells selected with the same antibodies that yielded variation in the thymocytes. Human CD34(+) stem cells were immunomagnetically selected using the class II QBEnd antibody (prevalent in clinical graft engineering) and the class III 8G12 antibody (common in diagnostic tests). Engraftment and T-cell reconstitution were examined after transplantation. Thymocytes selected with the 8G12 class III antibody have a higher TREC production than those selected with the QBEnd class II antibody. Of mice transplanted with cells selected using the 8G12 antibody, 50% had sjTREC production, compared with 14% of mice transplanted with cells selected using the clinically common antibody QBEnd. 8G12 thymic progenitors are characterized by higher quality in thymic distribution and higher activity in T-cell differentiation. Using class III antibody targeting the CD34 molecule resulted in increased T-cell reconstitution in the NOD/SCID mouse. Use of a single antibody epitope targeting the CD34 molecule may lead to loss of cells that might provide richer T-cell reconstitution. Use of different or multiple epitopes, targeting of alternate stem cell markers, or use of cell-depletion strategies might prevent this loss.

Published 7 February 2007 in Stem Cells, 25(2): 537-42.
Full-text of this article is available online (may require subscription).

© 2004-2008 Stem Cells Research Today. All Rights Reserved.