Specific binding, internalization, and degradation of human neutrophil activating factor by human polymorphonuclear leukocytes

Journal Article · Sun Oct 15 00:00:00 EDT 1989 · Journal of Biological Chemistry; (USA)

OSTI ID:5228734

Besemer, J; Hujber, A; Kuhn, B ^[1]

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1. Sandoz Forschungsinstitut, Vienna (Austria)

The interaction of {sup 125}I-labeled recombinant human neutrophil activating factor (NAF) with polymorphonuclear leukocytes (PMN) was studied by means of a radioreceptor assay. The binding was characterized by a rapid transition (t1/2 less than or equal to 1 min) from a pH 3-sensitive state at 4{degree}C to pH 3 resistance at 37{degree}C. This was not caused by internalization of NAF since pH 3-resistant bound iodinated NAF could still be exchanged by an excess of nonlabeled NAF, i.e. was dissociable. Internalized iodinated NAF was processed into trichloroacetic acid-soluble forms. Scatchard transformation of binding isotherms at 4 and 37{degree}C led to nonlinear curves, a finding which is consistent with the expression of two receptor populations, one with high (KD = 11-35 pM) and the other with lower affinity (KD = 640-830 pM) at 4 degrees C. Numbers of the low affinity binding sites were approximately 34,000, and those with high affinity were 5,200/PMN when estimated at 4 degrees C. Binding of iodinated NAF to PMN was specific since it could be competed by an excess of nonlabeled NAF but not by two other activators of PMN function, formylmethionyl-leucyl-phenylalanine or human recombinant granulocyte-macrophage colony-stimulating factor. In addition to human PMN, NAF also bound specifically to two human monocytic cell lines; however, only the low affinity binding site could be detected on these cells.

• OSTI ID: 5228734
• Journal Information: Journal of Biological Chemistry; (USA), Vol. 264:29; ISSN 0021-9258
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
PEPTIDES
BIOCHEMICAL REACTION KINETICS
AFFINITY
IODINE 125
LEUKOCYTES
MAN
NEUTROPHILS
RADIORECEPTOR ASSAY
RECEPTORS
TUMOR CELLS
ANIMAL CELLS
ANIMALS
BETA DECAY RADIOISOTOPES
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BODY FLUIDS
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
MAMMALS
MATERIALS
MEMBRANE PROTEINS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PRIMATES
PROTEINS
RADIOISOTOPES
REACTION KINETICS
TRACER TECHNIQUES
VERTEBRATES
550201* - Biochemistry- Tracer Techniques