Short communication: dynamic constraints on the second phase compartment of HIV-infected cells

Adam M Spivak1, S Alireza Rabi, Moira A McMahon

  • 1Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21218, USA.

Insights

Identifying the cells causing the second phase of HIV-1 viremia decay is crucial. Our study suggests differentiated macrophages are unlikely candidates due to a short reverse transcription-to-integration delay, impacting viral dynamics models.

Area of Science:

  • Virology
  • Immunology
  • Mathematical Modeling

Background:

  • The cellular reservoirs driving persistent Human Immunodeficiency Virus type 1 (HIV-1) replication during antiretroviral therapy (ART) remain incompletely understood.
  • Identifying these reservoirs is critical for developing strategies to achieve a functional cure for HIV-1.
  • Previous dynamic models of HIV-1 infection have proposed different cellular compartments responsible for viral decay phases.

Purpose of the Study:

  • To investigate the cellular candidates responsible for the second phase of HIV-1 viremia decay after initiating ART.
  • To evaluate the role of differentiated macrophages as a potential viral reservoir based on drug action and viral kinetics.
  • To refine mathematical models of HIV-1 dynamics by incorporating specific cellular properties.

Main Methods:

  • Utilized a dynamic mathematical model of HIV-1 infection and replication.
  • Incorporated the known sites of action for antiretroviral drugs, specifically integrase inhibitors like raltegravir.
  • Analyzed the impact of the intracellular time delay between reverse transcription and viral DNA integration in different cell types, focusing on differentiated macrophages.

Main Results:

  • The rapid decline in HIV-1 viremia observed with integrase inhibitors suggests a specific drug-target interaction.
  • Differentiated macrophages exhibit a short intracellular delay between reverse transcription and integration.
  • This short delay makes differentiated macrophages unlikely candidates for the persistent viral reservoir driving the second phase of viremia decay in standard viral dynamic models.

Conclusions:

  • Differentiated macrophages are poor candidates for the cellular compartment responsible for the second phase of HIV-1 decay under current viral dynamic model assumptions.
  • The kinetics of reverse transcription and integration in macrophages do not align with the observed viral load reduction patterns with integrase inhibitors.
  • Further research is needed to identify the specific cell types that constitute the latent HIV-1 reservoir and contribute to viral persistence during therapy.