Dichotomy in cross-clade reactivity and neutralization by HIV-1 sera: Implications for active and passive immunotherapy

Lisa A. Cavacini, Mark Duval, Ajay Patil, Charles Wood, Kenneth H. Mayer, Ruth M. Ruprecht, Marshall R. Posner

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


The identification of broadly reactive and cross-clade neutralizing antibodies will facilitate the development of a more universally effective vaccine for human immunodeficiency virus (HIV). Antibodies in sera from individuals infected with Clade B HIV bind native primary viral isolates, and virus binding correlates with neutralization and stable clinical disease. In this study, we quantified cross-clade antibody reactivity and neutralization by Clades B and C sera. Primary viral isolates were captured by serum IgG bound to anti-human IgG and quantitated as p24 released by lysis of captured virus. Neutralization was determined using PHA-stimulated PBMC. Clade B antibodies reacted more frequently with Clade B R5 virus, but positive sera captured quantitatively more X4 virus than R5 and R5X4 virus. Clade B sera reacted less frequently and captured less Clade C virus than Clade B virus. Antibodies in Clade C sera captured Clades B and C isolates with equal frequency and quantity. There was no difference in neutralization of Clade B virus by either group of sera; however, Clade C sera neutralized Clade C virus, whereas Clade B sera were ineffective against Clade C virus. Thus, there are distinct differences in cross-clade reactivity of and neutralization by antibodies induced in response to Clade C infection compared to Clade B infection. Understanding antibody responses to native virions after Clade C infection and cross clade antibody behavior has implications for understanding pathogenesis and vaccine development.

Original languageEnglish (US)
Pages (from-to)146-152
Number of pages7
JournalJournal of Medical Virology
Issue number2
StatePublished - Jun 2005


  • Cross-clade
  • Human immunodeficiency virus
  • Neutralization
  • Serum antibody

ASJC Scopus subject areas

  • Virology
  • Infectious Diseases


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