HIV-1 latency in actively dividing human T cell lines.
BACKGROUND
Eradication of HIV-1 from an infected individual cannot be achieved by current drug regimens. Viral reservoirs established early during the infection remain unaffected by anti-retroviral therapy and are able to replenish systemic infection upon interruption of the treatment. Therapeutic targeting of viral latency will require a better understanding of the basic mechanisms underlying the establishment and long-term maintenance of HIV-1 in resting memory CD4 T cells, the most prominent reservoir of transcriptional silent provirus. However, the molecular mechanisms that permit long-term transcriptional control of proviral gene expression in these cells are still not well understood. Exploring the molecular details of viral latency will provide new insights for eventual future therapeutics that aim at viral eradication.


RESULTS
We set out to develop a new in vitro HIV-1 latency model system using the doxycycline (dox)-inducible HIV-rtTA variant. Stable cell clones were generated with a silent HIV-1 provirus, which can subsequently be activated by dox-addition. Surprisingly, only a minority of the cells was able to induce viral gene expression and a spreading infection, eventhough these experiments were performed with the actively dividing SupT1 T cell line. These latent proviruses are responsive to TNFalpha treatment and alteration of the DNA methylation status with 5-Azacytidine or genistein, but not responsive to the regular T cell activators PMA and IL2. Follow-up experiments in several T cell lines and with wild-type HIV-1 support these findings.


CONCLUSIONS
We describe the development of a new in vitro model for HIV-1 latency and discuss the advantages of this system. The data suggest that HIV-1 proviral latency is not restricted to resting T cells, but rather an intrinsic property of the virus.
Jeeninga
Rienk E
RE
Laboratory of Experimental Virology, Department of Medical Microbiology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, The Netherlands. r.jeeninga@amc.uva.nl
Westerhout
Ellen M
EM
van Gerven
Marja L
ML
Berkhout
Ben
B
D002455:Cell Division; D002460:Cell Line; D015967:Gene Expression Regulation, Viral; D015497:HIV-1 / Q000235:genetics / Q000502:physiology*; D006801:Humans; D011533:Proviruses / Q000502:physiology*; D012367:RNA, Viral / Q000032:analysis / Q000235:genetics; D013601:T-Lymphocytes / Q000166:cytology* / Q000821:virology*; D014775:Virus Activation; D017735:Virus Latency / Q000235:genetics / Q000502:physiology*; D054322:tat Gene Products, Human Immunodeficiency Virus / Q000378:metabolism
D012367:RNA, Viral; D054322:tat Gene Products, Human Immunodeficiency Virus