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Updated: Aug 15, 2026
Amplifying and Quantifying HIV-1 RNA in HIV Infected Individuals with Viral Loads Below the Limit of Detection by Standard Clinical Assays
Published on: September 26, 2011
Quantitation of human immunodeficiency virus type 1 infection kinetics
D S Dimitrov1, R L Willey, H Sato
1Section on Membrane Structure and Function, National Cancer Institute, Bethesda, Maryland 20892.
Insights
Human immunodeficiency virus type 1 (HIV-1) infection kinetics in cell culture were modeled. Cell-to-cell transmission showed significantly higher infectivity than cell-free virus stocks, impacting infection rates.
Area of Science:
- Virology
- Immunology
- Mathematical Biology
Background:
- Human immunodeficiency virus type 1 (HIV-1) infection of CD4-positive T cells follows a three-stage process: latent, productive, and declining virus release.
- Understanding HIV-1 replication kinetics is crucial for developing effective antiviral strategies.
Purpose of the Study:
- To derive mathematical equations describing HIV-1 accumulation kinetics in cell culture during multiple infection rounds.
- To identify key parameters influencing HIV-1 infection dynamics and compare infectivity between cell-to-cell and cell-free transmission.
Main Methods:
- Developed mathematical models to describe HIV-1 kinetics in cell culture supernatants.
- Analyzed the infection rate constant (k) incorporating virion production (n) and infection cycle time (ti).
- Compared infectivity of cell-to-cell transmission versus cell-free virus stocks.
Main Results:
- The infection rate constant (k) is a critical determinant of HIV-1 infection kinetics.
- Cell-to-cell HIV-1 transmission exhibits 100-1000 times greater infectivity than cell-free virus stocks.
- Slow infection kinetics of an HIV-1 tat mutant result from reduced infectious particle production, not prolonged replication time.
Conclusions:
- Mathematical modeling provides insights into HIV-1 infection dynamics.
- Cell-to-cell transmission is a highly efficient mode of HIV-1 spread in vitro.
- HIV-1 particle infectivity and production numbers are key factors in determining infection progression.
Abstract:
Tissue culture infections of CD4-positive human T cells by human immunodeficiency virus type 1 (HIV-1) proceed in three stages: (i) a period following the initiation of an infection during which no detectable virus is produced; (ii) a phase in which a sharp increase followed by a peak of released progeny virions can be measured; and (iii) a final period when virus production declines. In this study, we have derived equations describing the kinetics of HIV-1 accumulation in cell culture supernatants during multiple rounds of infection. Our analyses indicated that the critical parameter affecting the kinetics of HIV-1 infection is the infection rate constant k = Inn/ti, where n is the number of infectious virions produced by one cell (about 10(2)) and ti is the time required for one complete cycle of virus infection (typically 3 to 4 days). Of particular note was our finding that the infectivity of HIV-1 during cell-to-cell transmission is 10(2) to 10(3) times greater than the infectivity of cell-free virus stocks, the inocula commonly used to initiate tissue culture infections. We also demonstrated that the slow infection kinetics of an HIV-1 tat mutant is not due to a longer replication time but reflects the small number of infectious particles produced per cycle.
