Alpha interferon restricts human T-lymphotropic virus type 1 and 2 de novo infection through PKR activation.
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| Abstract |
Type I interferon (IFN-I) inhibits the replication of different viruses. However, the effect of IFN-I on the human T-lymphotropic virus type 1 (HTLV-1) viral cycle is controversial. Here, we investigated the consequences of IFN-α addition for different steps of HTLV-1 and HTLV-2 infection. We first show that alpha interferon (IFN-α) efficiently impairs HTLV-1 and HTLV-2 de novo infection in a T cell line and in primary lymphocytes. Using pseudotyped viruses expressing HTLV-1 envelope, we then show that cell-free infection is insensitive to IFN-α, demonstrating that the cytokine does not affect the early stages of the viral cycle. In contrast, intracellular levels of Gag, Env, or Tax protein are affected by IFN-α treatment in T cells, primary lymphocytes, or 293T cells transfected with HTLV-1 or HTLV-2 molecular clones, demonstrating that IFN-α acts during the late stages of infection. We show that IFN-α does not affect Tax-mediated transcription and acts at a posttranscriptional level. Using either small interfering RNA (siRNA) directed against PKR or a PKR inhibitor, we demonstrate that PKR, whose expression is induced by interferon, plays a major role in IFN-α-induced HTLV-1/2 inhibition. These results indicate that IFN-α has a strong repressive effect on the HTLV-1 and HTLV-2 viral cycle during de novo infection of cells that are natural targets of the viruses.
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| Authors | Anne Cachat, Sébastien Alain Chevalier, Sandrine Alais, Nga Ling Ko, Lee Ratner, Chloé Journo, Hélène Dutartre, Renaud Mahieux |
| Journal | Journal of virology (J Virol) Vol. 87 Issue 24 Pg. 13386-96 (Dec 2013) ISSN: 1098-5514 [Electronic] United States |
| PMID | 24089560 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't) |
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