HIV-1 evades innate immune recognition through specific cofactor recruitment.

Abstract

HIV-1 is able to replicate in primary human macrophages without stimulating innate immunity despite reverse transcription of genomic RNA into double stranded DNA, an activity that might be expected to trigger innate pattern recognition receptors (PRRs). We hypothesized that, if correctly orchestrated HIV-1 uncoating and nuclear entry is important for evasion of innate sensors, then manipulation of specific interactions between HIV-1 capsid (CA) and host factors that putatively regulate these processes should trigger PRRs and stimulate type 1 interferon secretion. Here we show that HIV-1 CA mutants N74D and P90A, which are impaired for interaction with cofactors Cleavage and Polyadenylation Specificity Factor subunit 6 (CPSF6) and cyclophilins (Nup358 and CypA) respectively(1-2), cannot replicate in primary human monocyte derived macrophages (MDM) because they trigger innate sensors leading to nuclear translocation of NFκB and IRF3, the production of soluble type-1 interferon (IFN) and induction of an antiviral state. Depletion of CPSF6 with shRNA expression allows wild type virus to trigger innate sensors and interferon production. In each case, suppressed replication is rescued by IFN-receptor blockade demonstrating a role for IFN in restriction. IFN production is dependent on viral reverse transcription but not integration suggesting that a viral reverse transcription product comprises the HIV-1 pathogen associated molecular pattern (PAMP). Finally, we show that we can pharmacologically induce wild type HIV-1 infection to stimulate IFN secretion and an antiviral state using a non-immunosuppressive cyclosporine analogue. We conclude that HIV-1 has evolved to utilize CPSF6 and cyclophilins to cloak its replication allowing evasion of innate immune sensors and induction of a cell autonomous innate immune response in primary human macrophages (Extended Data Fig 1).