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Updated: May 11, 2026

Preparation and Use of HIV-1 Infected Primary CD4+ T-Cells as Target Cells in Natural Killer Cell Cytotoxic Assays
Published on: March 14, 2011
Primitive hematopoietic cells resist HIV-1 infection via p21
Jielin Zhang1, David T Scadden, Clyde S Crumpacker
1Division of Infectious Diseases, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02114, USA.
Abstract:
Hematopoietic stem cells are resistant to HIV-1 infection. Here, we report a novel mechanism by which the cyclin-dependent kinase inhibitor (CKI) p21(Waf1/Cip1/Sdi1) (p21), a known regulator of stem cell pool size, restricts HIV-1 infection of primitive hematopoietic cells. Modifying p21 expression altered HIV-1 infection prior to changes in cell cycling and was selective for p21 since silencing the related CKIs, p27(Kip1) and p18(INK4C), had no effect on HIV-1. We show that p21 blocked viral infection by complexing with HIV-1 integrase and aborting chromosomal integration. A closely related lentivirus with a distinct integrase, SIVmac-251, and the other cell-intrinsic inhibitors of HIV-1, Trim5alpha, PML, Murr1, and IFN-alpha, were unaffected by p21. Therefore, p21 is an endogenous cellular component in stem cells that provides a unique molecular barrier to HIV-1 infection and may explain how these cells remain an uninfected "sanctuary" in HIV disease.
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