Surface plasmon resonance analysis of gp17, a natural CD4 ligand from human seminal plasma inhibiting human immunodeficiency virus type-1 gp120-mediated syncytium formation

Eur J Biochem. 1997 Apr 1;245(1):208-13. doi: 10.1111/j.1432-1033.1997.00208.x.


We have previously isolated from human seminal plasma a CD4 ligand, the gp17 glycoprotein, which shares sequence identity with three previously identified proteins: secretory actin-binding protein (SABP) from seminal plasma, gross-cystic-disease fluid protein-15 (GCDFP-15) and prolactin-inducible protein (PIP) from breast tumor cells. Functions of these glycoproteins are unknown. To further characterize the physical interaction between gp17 and CD4 we used surface plasmon resonance and demonstrated that gp17-CD4 binding affinity is high. Competition experiments indicated that gp17 interferes with human immunodeficiency virus (HIV) envelope protein/CD4 binding, although it binds to a site distinct from but close to the gp120-binding site. We observed moreover that gp17 inhibits syncytium formation between transfected cells expressing the wild-type HIV-1 envelope glycoprotein and CD4, respectively. Our results suggest that gp17, which may function as an immunomodulatory CD4-binding factor playing a role at insemination, may also play a role in controlling HIV spread in the sexual tract.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apolipoproteins D
  • Apolipoproteins*
  • Binding, Competitive
  • CD4 Antigens / metabolism*
  • Carrier Proteins / chemistry*
  • Carrier Proteins / pharmacology
  • Giant Cells / drug effects*
  • Glycoproteins / chemistry*
  • Glycoproteins / pharmacology
  • HIV Envelope Protein gp120 / metabolism*
  • HIV-1 / drug effects*
  • HeLa Cells
  • Humans
  • Kinetics
  • Membrane Transport Proteins*
  • Recombinant Proteins / metabolism
  • Semen / chemistry*


  • APOD protein, human
  • Apolipoproteins
  • Apolipoproteins D
  • CD4 Antigens
  • Carrier Proteins
  • Glycoproteins
  • HIV Envelope Protein gp120
  • Membrane Transport Proteins
  • PIP protein, human
  • Recombinant Proteins