Determining the precise lifespan of human T-cell is challenging due to the inability of standard techniques to distinguish between dividing and dying cells. Here, we measured the lifespan of a pool of T cells that were derived from a single cell ‘naturally’ labelled with a single integrated clone of a replication-incompetent HIV-1 provirus.
Utilizing a combination of techniques, we were able to sequence/map an integration site of a unique provirus with a stop codon at position 42 of the HIV-1 protease. In-vitro reconstruction of this provirus into an infectious clone confirmed its inability to replicate. By combining cell separation and integration site-specific PCR, we were able to follow the fate of this single provirus in multiple T-cell subsets over a 20-year period. As controls, a number of additional integrated proviruses were also sequenced.
The replication-incompetent HIV-1 provirus was solely contained in the pool of effector memory CD4+ T cells for 17 years. The percentage of the total effector memory CD4+ T cells containing the replication-incompetent provirus peaked at 1% with a functional half-life of 11.1 months. In the process of sequencing multiple proviruses, we also observed high levels of lethal mutations in the peripheral blood pool of proviruses.
These data indicate that human effector memory CD4+ T cells are able to persist in vivo for more than 17 years without detectably reverting to a central memory phenotype. A secondary observation is that the fraction of the pool of integrated HIV-1 proviruses capable of replicating may be considerably less than the 12% currently noted in the literature.
aClinical and Molecular Retrovirology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda
bClinical Services Program, Applied and Development Research Directorate, Leidos Biomedical Research Incorporated, Frederick National Laboratory for Cancer Research, Frederick, Maryland, USA.
Correspondence to H. Clifford Lane, MD, 9000 Rockville Pike, CRC, Building 10, Rm. 4-1479, MSC 1460, Bethesda, MD 20892, USA. Tel: +1 301 496 7196; fax: +1 301 480 5560; e-mail: CLANE@niaid.nih.gov
Received 14 October, 2013
Revised 23 January, 2014
Accepted 23 January, 2014
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