Binding of recombinant HIV coat protein gp120 to human monocytes

Journal Article · Fri Feb 15 04:00:00 EST 1991 · Journal of Immunology; (USA)

OSTI ID:6056895

Finbloom, D S; Hoover, D L; Meltzer, M S ^[1]

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1. Food and Drug Administration, Bethesda, MD (USA)

Inasmuch as the exact level of CD4 Ag expression on macrophages is controversial and because HIV may interact with macrophages in a manner different from that on T cells, we analyzed the binding of gp120 to freshly isolated and cultured monocytes. rgp120 was iodinated using the lactoperoxidase method to a sp. act. of 600 Ci/mmol. Highly purified monocytes (greater than 90%) were isolated from the leukapheresed blood of normal volunteers by Ficoll-Hypaque sedimentation followed by countercurrent centrifugal elutriation and cultured 7 days in DMEM supplemented with 1000 U/ml macrophage CSF in 10% human serum. Whereas MOLT/4 cells consistently bound freshly prepared 125I-rgp120 at 80% specificity with 5100 +/- 700 mol/cell, MCSF cultured monocytes bound rgp120 at only 0 to 20% specificity and 420 +/- 200 mol/cell. Most of the radioactivity bound by these cells could not be blocked by the addition of unlabeled rgp120. In contrast, the U937 myeloid cell line bound rgp120 with 50% specificity and about 2500 mol/cell. Whereas the antibody OKT4a (anti-CD4) blocked 80% of the binding on MOLT/4 cells and 50% on U937 cells, binding was only inhibited on the average of 6% on cultured monocytes. When soluble rCD4 was used as an inhibitor, binding to MOLT/4 cells was blocked by 80%. In contrast, binding to cultured monocytes was inhibited by 28%. HIV infectivity was blocked by similar concentrations of OKT4a. These observations suggest that although most binding of gp120 to cultured monocytes is not to the CD4 determinant, several hundred molecules do bind to a CD4-like molecule which promotes virus entry and replication.

• OSTI ID: 6056895
• Journal Information: Journal of Immunology; (USA), Journal Name: Journal of Immunology; (USA) Vol. 146:4; ISSN JOIMA; ISSN 0022-1767
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES
AIDS
AIDS VIRUS
ANIMAL CELLS
ANIMALS
BETA DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BODY FLUIDS
CONNECTIVE TISSUE CELLS
DAYS LIVING RADIOISOTOPES
DISEASES
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IMMUNE SYSTEM DISEASES
INFECTIOUS DISEASES
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INTERMEDIATE MASS NUCLEI
IODINE 125
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KINETICS
LEUKOCYTES
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MAMMALS
MAN
MATERIALS
MICROORGANISMS
MONOCYTES
NUCLEI
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ORGANIC COMPOUNDS
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PATHOGENESIS
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PHAGOCYTES
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PROTEINS
RADIOISOTOPES
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TRACER TECHNIQUES
VERTEBRATES
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