title: Development of human lymphohematopoiesis defined by CD34 and CD81 expression.
abstract: Human blood cells, except for erythrocytes and platelets, express CD81, a member of the transmembrane 4 superfamily (TM4SF). CD81 is also expressed on most of human immature hematopoietic cells, CD34+ cells, which are divided into three populations according to the expression of CD34 and CD81; CD34+CD81+, CD34+CD81(High) and CD34(Low)CD81+. Myeloid and lymphoid progenitors exist in the CD34+CD81+ population, and megakaryocytic progenitors are only in CD34(Low)CD81+ population. Erythroid and multipotential progenitors are shared by CD34+CD81+ and CD34(Low)CD81+ populations, but multipotential progenitors in the CD34+CD81+ population have already lost most of their myeloid potential. NK cells and mast cells can be generated from all three populations. Long-term repopulating (LTR) lymphohematopoietic stem cells are present in the CD34+CD81+ population. Based on these findings, we propose a model for the development of CD34+CD81+ lymphohematopoietic stem cells. Along the differentiation cascade from CD34+CD81+ lymphohematopoietic stem cells, there appear to be pathways to CD34(Low)CD81 + or CD34+CD81(High) cells, even if they are indirect. CD34(Low)CD81+ pathways define the loss of LTR ability, and lymphoid and myeloid potentials, whereas CD34+CD81(High) pathways represent the exclusive commitment to NK cells and mast cells.
authors.affiliation: Division of Cellular Therapy, The Advanced Clinical Research Center, The Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan. tsujik@ims.u-tokyo.ac.jp
authors.forename: Kohichiro
authors.initials: K
authors.lastname: Tsuji
authors.forename: M A
authors.initials: MA
authors.lastname: Feng
authors.forename: Dan
authors.initials: D
authors.lastname: Wang
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000378:metabolism / Q000502:physiology*; D018952:Antigens, CD34; D001773:Blood Cells / Q000166:cytology; D002454:Cell Differentiation; D006801:Humans; D038041:Lymphopoiesis; D008565:Membrane Proteins / Q000378:metabolism / Q000502:physiology*; D060225:Tetraspanin 28
chemical_list: D015703:Antigens, CD; D018952:Antigens, CD34; C554798:CD81 protein, human; D008565:Membrane Proteins; D060225:Tetraspanin 28