IL-3 promotes basophilic differentiation of KU812 cells through high affinity binding sites.
The myeloid precursor cell line KU812 exhibits a constitutive potential to differentiate into basophilic cells. In the present study, the influence of recombinant human (rh)IL-2, rhIL-3, and recombinant human granulocyte-macrophage-CSF on basophilic differentiation of KU812-F cells was studied. Of all cytokines tested, rhIL-3 induced a significant increase in formation of metachromatically granulated cells (from 10% in control cultures up to 30% in cultures supplemented with 100 U/ml of rhIL-3) as well as dose-dependent (1.5- to 3 fold) increase in cellular histamine in KU812-F cell cultures. In addition, KU812-F cells exposed to rhIL-3 bound more IgE antibody than cells cultured in control medium with up to 3.3-fold increases in the mean fluorescence intensity on days 2 and/or 5 compared with control (p less than 0.001). RhIL-3 failed to induce significant changes in expression of the Tac-reactive subunit of the IL-2R (CD25), surface aminopeptidase N (CD13), ICAM-1 Ag (CD54), or CD40 Ag on KU812-F cells. To investigate the mechanism of IL-3 action on KU812-F cells, receptor analyses were performed by using 125I-radiolabeled rhIL-3. Quantitative binding studies and Scatchard plot analyses revealed the presence of a single class of 1910 to 2460 high affinity IL-3-binding sites per KU812-F cell with an apparent dissociation constant of 1.22 to 2.35 x 10(-9) M. Together, these results show that rhIL-3 promotes basophilic differentiation of KU812-F cells through a specific receptor.
Valent
P
P
I. Medical Department, University of Vienna, Austria.
Besemer
J
J
Kishi
K
K
Kaltenbrunner
R
R
Kuhn
B
B
Maurer
D
D
Lechner
K
K
Bettelheim
P
P
D015703:Antigens, CD / Q000032:analysis; D000944:Antigens, Differentiation, B-Lymphocyte / Q000378:metabolism; D001491:Basophils / Q000166:cytology*; D001685:Biological Factors / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D016207:Cytokines; D006410:Hematopoiesis / Q000187:drug effects; D006801:Humans; D007073:Immunoglobulin E / Q000378:metabolism; D066298:In Vitro Techniques; D007377:Interleukin-3 / Q000494:pharmacology*; D011961:Receptors, Fc / Q000378:metabolism; D017455:Receptors, IgE; D011971:Receptors, Immunologic / Q000502:physiology*; D016185:Receptors, Interleukin-3; D011994:Recombinant Proteins
D015703:Antigens, CD; D000944:Antigens, Differentiation, B-Lymphocyte; D001685:Biological Factors; D016207:Cytokines; D007377:Interleukin-3; D011961:Receptors, Fc; D017455:Receptors, IgE; D011971:Receptors, Immunologic; D016185:Receptors, Interleukin-3; D011994:Recombinant Proteins; D007073:Immunoglobulin E