Unintegrated human immunodeficiency virus type 1 DNA in chronically infected cell lines is not correlated with
N J Besansky1, S T Butera, S Sinha
1Retrovirus Diseases Branch, Centers for Disease Control, Atlanta, Georgia 30333.
Insights
Unintegrated human immunodeficiency virus type 1 (HIV-1) DNA is unstable in infected cells and arises from continuous reinfection. Antiviral treatments like AZT or soluble CD4 temporarily reduce this viral DNA.
Area of Science:
- Virology
- Molecular Biology
- Immunology
Background:
- Human immunodeficiency virus type 1 (HIV-1) establishes chronic infections.
- Understanding the lifecycle of HIV-1, including viral DNA dynamics, is crucial for developing effective therapies.
Purpose of the Study:
- To investigate the stability and origin of unintegrated HIV-1 DNA in chronically infected cell lines.
- To assess the impact of antiviral treatments on unintegrated viral DNA levels.
Main Methods:
- Polymerase chain reaction (PCR)-based assay on total cell lysates.
- Flow cytometry to quantify surface CD4 receptor expression.
- Treatment of infected cell lines (ACH-2, J1, OM-10.1) with 3'-azido-3'-deoxythymidine (AZT) and soluble CD4.
Main Results:
- Unintegrated HIV-1 DNA was detected in chronically infected T-lymphocytic and promyelocytic cell lines.
- AZT or soluble CD4 treatment inhibited unintegrated viral DNA accumulation by approximately 10-fold within 72 hours.
- Removal of AZT led to recovery of unintegrated viral DNA levels within 72 hours, indicating instability and continuous reinfection.
- CD4 receptor levels did not appear to be rate-limiting for reinfection, as demonstrated by J1 cells with low CD4 but high unintegrated DNA.
Conclusions:
- Unintegrated HIV-1 DNA is unstable in these cell lines and results from ongoing reinfection.
- Antiviral interventions targeting viral DNA accumulation are effective but reversible.
- CD4 receptor expression levels may not be the sole determinant of HIV-1 reinfection rates.
Abstract:
Using a polymerase chain reaction-based assay on total cell lysates, we have detected unintegrated human immunodeficiency virus type 1 (HIV-1) DNA in chronically infected T-lymphocytic (ACH-2, J1) and promyelocytic (OM-10.1) cell lines. Treatment with 3'-azido-3'-deoxythymidine (AZT) or soluble CD4 inhibited accumulation of unintegrated viral DNA about 10-fold within 72 h; removal of AZT permitted recovery to pretreatment levels within 72 h. Our results indicate that unintegrated HIV-1 DNA is unstable in these cell lines and originates from a continuous process of reinfection. OM-10.1 cells had relatively high levels of surface CD4 by flow cytometry and high levels of unintegrated viral DNA by polymerase chain reaction. ACH-2 cells had very low levels of both surface CD4 and unintegrated viral DNA. However, J1 cells, with surface CD4 below the level of detection of flow cytometry had a high level of unintegrated viral DNA similar to that of OM-10.1 cells. This implies that the number of CD4 receptors is not rate limiting for reinfection.
