CD226 is expressed on the megakaryocytic lineage from hematopoietic stem cells/progenitor cells and involved in its polyploidization.
OBJECTIVE
In this study, we examined the expression of CD226 on megakaryocytic, granulocytic and erythroid lineage from hematopoietic stem cells/progenitor cells in adult and fetus and its potential role in megakaryocytic maturation.


METHODS
CD34(+) cells from adult and fetus were induced to differentiate toward the megakaryocytic lineage by thrombopoietin (TPO) and the granulocytic lineage by granulocyte colony-stimulating factor (G-CSF), respectively. Mononuclear cells from fetal liver and CD34(+) cells from adult were induced to differentiate toward erythroid-lineage by erythropoiesis (EPO). We investigated the expression of CD226 and lymphocyte function associated antigen-1 (LFA-1) (CD11a) during hemopoiesis. We also studied the effect of CD226 monoclonal antibody (MoAb) and LFA-1 MoAb on megakaryocyte with antibody cross-liking technique.


RESULTS
CD34(+) cells from adult and fetus and TPO-induced CD41(+) cells all expressed CD226 molecule. CD226 was not expressed on erythroid progenitor cells and erythroblasts and most cells of granulocytic lineage although G-CSF induced a significant increase of the expression of CD226 on CD34(+) cells in early period of time. CD226 MoAb acts on megakaryocytes by inducing intracellular calcium mobilization. The expression of LFA-1 decreased significantly at late stage of differentiation and maturation of fetal megakaryocytes whereas the expression of LFA-1 on adult megakaryocytes retained at a high level. CD226 MoAb in combination with LFA-1 MoAb shifted the ploidy of generated megakaryocytes from adult-derived CD34(+) cells to higher classes significantly although CD226 and LFA-1 MoAb slightly increased the ploidy of the generated megakaryocytes individually. CD226 MoAb or LFA-1 MoAb or CD226 MoAb plus LFA-1 MoAbs did not increase the ploidy of the generated megakaryocytes from fetus-derived CD34(+) cells.


CONCLUSIONS
CD226 molecules play an important role in maturation of the megakaryocytes in combination with LFA-1.
Ma
Dongchu
D
Department of Immunology, The Fourth Military Medical University, Xi'an, Shaanxi, China.
Sun
Yinghui
Y
Lin
Di
D
Wang
Haoyang
H
Dai
Bing
B
Zhang
Xinghai
X
Ouyang
Weiming
W
Jian
Jinlong
J
Jia
Wei
W
Xu
Xiaoguang
X
Jin
Boquan
B
D000328:Adult; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D018952:Antigens, CD34; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis / Q000276:immunology / Q000502:physiology*; D020013:Calcium Signaling / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D019070:Cell Lineage; D002478:Cells, Cultured; D005333:Fetus; D016179:Granulocyte Colony-Stimulating Factor / Q000494:pharmacology; D006098:Granulocytes / Q000166:cytology; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D006801:Humans; D008099:Liver / Q000166:cytology / Q000196:embryology; D016169:Lymphocyte Function-Associated Antigen-1 / Q000032:analysis / Q000276:immunology / Q000502:physiology*; D008533:Megakaryocytes / Q000166:cytology* / Q000378:metabolism; D011123:Polyploidy; D013926:Thrombopoietin / Q000494:pharmacology; D000098862:T Lineage-Specific Activation Antigen 1
D000911:Antibodies, Monoclonal; D018952:Antigens, CD34; D000945:Antigens, Differentiation, T-Lymphocyte; D000098862:T Lineage-Specific Activation Antigen 1; D016169:Lymphocyte Function-Associated Antigen-1; D016179:Granulocyte Colony-Stimulating Factor; D013926:Thrombopoietin