The microbicide cyanovirin-N expressed on the surface of commensal bacterium Streptococcus gordonii captures HIV-1

AIDS. 2002 Jul 5;16(10):1351-6. doi: 10.1097/00002030-200207050-00006.

Abstract

Objective: To explore the feasibility of expressing the potent HIV-inactivating protein, cyanovirin-N (CV-N), in the human commensal bacterium Streptococcus gordonii, as a possible approach for local delivery of CV-N to prevent sexual transmission of HIV-1.

Design and methods: To express CV-N in S. gordonii, we used the host-vector system we had previously developed. CV-N was expressed as a fusion protein both attached to the bacterial surface and secreted in soluble form in the supernatant of liquid cultures. The soluble form of recombinant CV-N was tested for gp120-binding activity in an enzyme-linked immunosorbent assay, whereas S. gordonii strain expressing CV-N on the surface was analyzed in an in vitro HIV capturing assay.

Results: Two recombinant S. gordonii strains secreting or displaying CV-N on the bacterial surface were constructed and the expression of CV-N was confirmed by immunoblot and flow-cytometric analysis. The secreted form of recombinant CV-N exhibited a concentration-dependent binding to the envelope glycoprotein gp120 of HIV-1, whereas CV-N displayed on the bacterial surface was able to capture HIV virions efficiently.

Conclusion: The anti-HIV protein CV-N in S. gordonii was expressed in a biologically active form. This represents a first step in the development of a system to deliver and maintain an effective concentration of a microbicide in the vaginal mucosa.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Bacterial Proteins / biosynthesis
  • Bacterial Proteins / metabolism*
  • Carrier Proteins / analysis
  • Carrier Proteins / biosynthesis
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism*
  • Flow Cytometry
  • HIV Envelope Protein gp120 / metabolism
  • HIV-1 / metabolism*
  • Immunoblotting
  • Protein Binding
  • Protein Engineering
  • Recombinant Fusion Proteins / analysis
  • Recombinant Fusion Proteins / biosynthesis
  • Streptococcus / metabolism*

Substances

  • Bacterial Proteins
  • Carrier Proteins
  • HIV Envelope Protein gp120
  • Recombinant Fusion Proteins
  • cyanovirin N