CD99 expressed on human mobilized peripheral blood CD34+ cells is involved in transendothelial migration.
Hematopoietic progenitor cell trafficking is an important phenomenon throughout life. It is thought to occur in sequential steps, similar to what has been described for mature leukocytes. Molecular actors have been identified for each step of leukocyte migration; recently, CD99 was shown to play a part during transendothelial migration. We explored the expression and role of CD99 on human hematopoietic progenitors. We demonstrate that (1) CD34+ cells express CD99, albeit with various intensities; (2) subsets of CD34+ cells with high or low levels of CD99 expression produce different numbers of erythroid, natural killer (NK), or dendritic cells in the in vitro differentiation assays; (3) the level of CD99 expression is related to the ability to differentiate toward B cells; (4) CD34+ cells that migrate through an endothelial monolayer in response to SDF-1alpha and SCF display the highest level of CD99 expression; (5) binding of a neutralizing antibody to CD99 partially inhibits transendothelial migration of CD34+ progenitors in an in vitro assay; and (6) binding of a neutralizing antibody to CD99 reduces homing of CD34+ progenitors xenotransplanted in NOD-SCID mice. We conclude that expression of CD99 on human CD34+ progenitors has functional significance and that CD99 may be involved in transendothelial migration of progenitors.
Imbert
Anne-Marie
AM
Centre de Thérapie Cellulaire et Génique, Institut Paoli-Calmettes, Centre Régional de Lutte Contre le Cancer Provence-Alpes-Côte d'Azur, 232 boulevard Sainte Marguerite, 13273 Marseille Cedex 9, France. imbertam@marseille.fnclcc.fr
Belaaloui
Ghania
G
Bardin
Florence
F
Tonnelle
Cecile
C
Lopez
Marc
M
Chabannon
Christian
C
D000071443:12E7 Antigen; D000818:Animals; D000911:Antibodies, Monoclonal / Q000008:administration & dosage; D015703:Antigens, CD / Q000378:metabolism*; D018952:Antigens, CD34 / Q000097:blood; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D002460:Cell Line; D002465:Cell Movement / Q000276:immunology; D003114:Colony-Forming Units Assay; D004730:Endothelium, Vascular / Q000166:cytology / Q000276:immunology; D005312:Fetal Blood / Q000166:cytology / Q000276:immunology; D006410:Hematopoiesis / Q000276:immunology; D019650:Hematopoietic Stem Cell Mobilization; D006412:Hematopoietic Stem Cells / Q000276:immunology* / Q000502:physiology*; D006801:Humans; D066298:In Vitro Techniques; D007231:Infant, Newborn; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D009500:Neutralization Tests; D036102:Peripheral Blood Stem Cell Transplantation; D014183:Transplantation, Heterologous
D000071443:12E7 Antigen; D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D018952:Antigens, CD34; C061828:CD99 protein, human; D015815:Cell Adhesion Molecules