New approaches for quantitating the inhibition of HIV-1 replication by antiviral drugs in vitro and in vivo

Moira A. McMahon, Lin Shen, Robert F. Siliciano

Research output: Contribution to journalReview articlepeer-review

17 Scopus citations


PURPOSE OF REVIEW: With highly active antiretroviral therapy, HIV-1 infection has become a manageable lifelong disease. Developing optimal treatment regimens requires understanding how to best measure anti-HIV activity in vitro and how drug dose-response curves generated in vitro correlate with in-vivo efficacy. RECENT FINDINGS: Several recent studies have indicated that conventional multiround infectivity assays are inferior to single cycle assays at both low and high levels of inhibition. Multiround infectivity assays can fail to detect subtle but clinically significant anti-HIV activity. The discoveries of the anti-HIV activity of the hepatitis B drug entecavir and the herpes simplex drug acyclovir were facilitated by single-round infectivity assays. Recent studies using a single-round infectivity assay have shown that a previously neglected parameter, the dose-response curve slope, is an extremely important determinant of antiviral activity. Some antiretroviral drugs have steep slopes that result in extraordinary levels of antiviral activity. The instantaneous inhibitory potential, the log reduction in infectivity in a single-round assay at clinical drug concentrations, has been proposed as a novel index for comparing antiviral activity. SUMMARY: Among in-vitro measures of antiviral activity, single-round infection assays have the advantage of measuring instantaneous inhibition by a drug. Re-evaluating the antiviral activity of approved HIV-1 drugs has shown that the slope parameter is an important factor in drug activity. Determining the instantaneous inhibitory potential by using a single-round infectivity assay may provide important insights that can predict the in-vivo efficacy of anti-HIV-1 drugs.

Original languageEnglish (US)
Pages (from-to)574-582
Number of pages9
JournalCurrent opinion in infectious diseases
Issue number6
StatePublished - Dec 2009


  • HIV-1
  • Highly active antiretroviral therapy
  • Instantaneous inhibitory potential
  • Phenotypic assay
  • Single-round infectivity assay
  • Slope

ASJC Scopus subject areas

  • Microbiology (medical)
  • Infectious Diseases


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