Conformational changes in env oligomer induced by an antibody dependent on the V3 loop base

Lisa Cavacini, Mark Duval, Leslie Song, Rebecca Sangster, Shi Hua Xiang, Joseph Sodroski, Marshall Posner

Research output: Contribution to journalArticlepeer-review

49 Scopus citations


Objective: The HIV-1 env oligomer is structured such that conserved, neutralizing epitopes are obscured by gp120 variable loops. We have studied the ability of an IgG2 human monoclonal antibody (hmAb), F425 B4e8 (B4e8), dependent upon the base of the V3 loop, to induce conformational changes in the env oligomer. Design: The effect of B4e8 antibody on the exposure of neutralizing epitopes and viral neutralization was studied in combination with other hmAb. Methods: Epitope exposure and viral neutralization was determined using native, intact primary isolate virions. Results: B4e8 antibody neutralizes infection and binds to HIV-infected cells and primary isolate virions. B4e8 and 2G12 enhanced the binding of each other to infected cells or virus and the combination resulted in synergistic neutralization. B4e8 also enhanced the binding of CD4i and CD4 binding site antibodies. Conclusions: The conserved epitopes exposed by B4e8 are similar to those exposed by the movement of the variable loops following CD4 engagement. Further studies with select antibody combinations should provide important information for the design of effective immunotherapeutic agents.

Original languageEnglish (US)
Pages (from-to)685-689
Number of pages5
Issue number5
StatePublished - Mar 28 2003
Externally publishedYes


  • Conformational changes
  • Monoclonal antibody
  • env oligomer

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology
  • Infectious Diseases


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