Identification and characterization of a functional receptor for interferon-gamma on a megakaryocytic cell line.
We have previously shown that human interferon-gamma (Hu-IFN-gamma) induces platelets to become efficient effector cells, capable of killing young larvae of the parasite Schistosoma mansoni. Recently, binding sites for IFN-gamma on platelets have been characterized. We show here the presence of high-affinity receptors for IFN-gamma on the surface of the human megakaryocytic Dami cell line. Scatchard analysis indicated the presence of about 11,000 binding sites per cell, with a kd of 3 +/- 0.5 x 10(-10) mol/L; the apparent molecular weight of the receptor was 90 Kd. Receptor-bound 125I Hu-recombinant IFN-gamma was rapidly internalized and degraded when the temperature was increased from 4 degrees C to 37 degrees C. The half-life of this receptor was about 7 hours, and pretreatment of cells with IFN-gamma or phorbol myristate acetate had very little effect on the surface receptor number and no detectable effect on IFN-gamma receptor messenger RNA (mRNA) expression. The receptor was functional, because 24 hours of treatment with IFN-gamma led to the increase of HLA class I mRNA expression and to the initiation of HLA class II mRNA expression. These effects were selective because platelet glycoprotein Ib, IIb, or IIIa mRNA expression and cell proliferation were unaffected.
Monté
D
D
Centre d'Immunologie et de Biologie Parasitaire, Unité mixte INSERM 167-CNRS 624, Institut Pasteur de Lille, France.
Wietzerbin
J
J
Pancré
V
V
Merlin
G
G
Greenberg
S M
SM
Kusnierz
J P
JP
Capron
A
A
Auriault
C
C
D015152:Blotting, Northern; D002460:Cell Line; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism*; D007457:Iodine Radioisotopes; D007700:Kinetics; D008533:Megakaryocytes / Q000648:ultrastructure*; D011233:Precipitin Tests; D011485:Protein Binding; D012333:RNA, Messenger / Q000032:analysis; D011971:Receptors, Immunologic / Q000235:genetics / Q000502:physiology*; D017471:Receptors, Interferon; D011994:Recombinant Proteins
D007457:Iodine Radioisotopes; D012333:RNA, Messenger; D011971:Receptors, Immunologic; D017471:Receptors, Interferon; D011994:Recombinant Proteins; D007371:Interferon-gamma