Specific binding of placental acidic isoferritin to cells of the T-cell line HD-MAR.
Acidic placental isoferritin inhibited the blastogenic response of peripheral human lymphocytes to T-cell activating lectins. We measured specific binding of radioiodinated placental isoferritin to cells of the T-cell line HD-MAR and found specific high-affinity binding. Binding was faster and more ferritin was bound at 37 degrees C than at 4 degrees C. Displacement experiments indicated that most of the binding occurred at the cell surface. Acidic placental ferritin and isolated H-type ferritin subunits but not isolated L-type subunits, competed for the binding. Scatchard plot analysis showed characteristics of a single binding species with a dissociation constant (Kd) of 1.3-4.4 x 10(-11) M. The results suggest the presence of receptors for acidic isoferritin on T-lymphocytes and thus, a regulatory role for the acidic ferritin H-type subunit in T-cell function.
Konijn
A M
AM
Department of Nutrition, Hebrew University-Hadassah Medical School, Jerusalem, Israel.
Meyron-Holtz
E G
EG
Levy
R
R
Ben-Bassat
H
H
Matzner
Y
Y
D001667:Binding, Competitive; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D005293:Ferritins / Q000378:metabolism*; D006801:Humans; D010920:Placenta / Q000378:metabolism; D011485:Protein Binding; D013601:T-Lymphocytes / Q000378:metabolism*; D014407:Tumor Cells, Cultured
C020391:acidic isoferritin; D005293:Ferritins