Human alpha-fetoprotein binds to primary macrophages.

We have previously reported that alpha-fetoprotein (AFP) inhibits infection of human monocyte-derived macrophages (MDM) by R5-HIV-1 strains and that a peptide mimicking the clade B HIV-1 gp120 consensus V3 domain (V3Cs) binds to CCR5. We demonstrate here that AFP binds high- and low-affinity binding sites of MDM, characterized, respectively, by 5.15 and 100nM K(d) values.

Glycans are involved in RANTES binding to CCR5 positive as well as to CCR5 negative cells.

We show that cell surface glycans, sialic acid and mannose-containing species, are involved beside glycosaminoglycans (GAGs), heparan sulfate and chondroitin sulfate in the binding of full length (1--68) RANTES not only to CCR5 positive human primary lymphocytes or macrophages but also to CCR5 negative monocytic U937 cells. Pretreating the cells with neuraminidase, heparitinase, chondroitinase or adding soluble glycans such as mannan or GAGs (heparin or chondroitin sulfate), significantly inhibited RANTES binding. Such effects were not observed with truncated (10--68) RANTES.

Human alpha1-acid glycoprotein binds to CCR5 expressed on the plasma membrane of human primary macrophages.

We have reported previously that human alpha(1)-acid glycoprotein (AGP) inhibits the infection of human monocyte-derived macrophages (MDM) by R5 HIV-1, and that a disulphide-bridged peptide mimicking the clade B HIV-1 gp120 consensus V3 domain (V3Cs) binds specifically to CCR5 (the major co-receptor of R5 HIV strains) on these cells [Seddiki, Rabehi, Benjouad, Saffar, Ferriere, Gluckman and Gattegno (1997) Glycobiology 7, 1229-1236]. The present study demonstrates that AGP binds specifically to MDM at high- and low-affinity binding sites with K(d) values of 16 nM and 4.9 microM respectively.

Inhibition of human immunodeficiency virus infection of CD4+ cells by CD4-free glycopeptides from monocytic U937 cells.

We have previously demonstrated that human immunodeficiency virus (HIV) envelope glycoproteins have specific carbohydrate-binding properties for mannosyl/N-acetylglucosaminyl residues presented at high density on a carrier in vitro. Here, we investigated whether HIV envelope glycoprotein gp120 was able to interact with surface membrane carbohydrates of CD4+ cells by means of such lectin-carbohydrate interactions. CD4-free tryptic glycopeptides, prepared from the membrane of CD4+ monocytic U937 cells and partially purified by ConA-agarose affinity chromatography, could be eluted by mannan but not by methyl-alpha-mannose or methyl-alpha-glucose, which strongly suggests that they displayed oligomannosidic structures.