title: Analysis of natural killer (NK) cell activity and adhesion molecules on NK cells from umbilical cord blood.
abstract: The activity of natural killer (NK) cells in human umbilical cord blood (CB) has been reported to be low, compared with that in adult peripheral blood (PB) in vitro. To examine the cause of this, after dividing the CD56+/CD3- cells in CB and PB into CD56bright and CD56dim NK cells, the NK cell activities and the expression of various surface antigens were assayed for each fraction. The NK cell activity of CD56dim NK cells in CB was significantly lower than that in PB (P = 0.0003), whereas, there was no significant difference between the NK cell activity of CD56bright NK cells in PB and CB. The expression levels of adhesion molecules (CD2, CD11a, CD18, DNAX accessory molecule-1), CD16, and CD57 for CD56dim NK cells in CB were significantly lower than those in PB, and approximately one-third of CB CD56dim NK cells were capable of forming conjugates with K562 cells, compared with PB CD56dim NK cells. Furthermore, the inhibition of both the NK cell activities and binding of CD56dim NK cells in PB and CB by monoclonal antibody against each of these adhesion molecules suggests that they play an important role in NK cell activity. These findings show that the low NK cell activity in CB is caused by the low NK cell activity of CD56dim NK cells and that the low expression level of adhesion molecules on CB CD56dim NK cells may contribute to this low NK cell activity.
authors.affiliation: Department of Transfusion Medicine, Division of Hematology and Oncology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan. ta@hyo-med.ac.jp
authors.forename: Hidehisa
authors.initials: H
authors.lastname: Tanaka
authors.forename: Shunro
authors.initials: S
authors.lastname: Kai
authors.forename: Masao
authors.initials: M
authors.lastname: Yamaguchi
authors.forename: Mahito
authors.initials: M
authors.lastname: Misawa
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Fujimori
authors.forename: Masuji
authors.initials: M
authors.lastname: Yamamoto
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hara
mesh_terms: D000911:Antibodies, Monoclonal / Q000494:pharmacology; D019002:CD56 Antigen / Q000032:analysis; D002448:Cell Adhesion / Q000187:drug effects; D015815:Cell Adhesion Molecules / Q000032:analysis / Q000276:immunology*; D003602:Cytotoxicity, Immunologic; D005312:Fetal Blood / Q000276:immunology*; D005434:Flow Cytometry; D006801:Humans; D020014:K562 Cells; D007694:Killer Cells, Natural / Q000737:chemistry / Q000166:cytology / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D019002:CD56 Antigen; D015815:Cell Adhesion Molecules