Detailed Characterization of Early HIV-1 Replication Dynamics in Primary Human Macrophages

• Main Authors: David Alejandro Bejarano, Maria C. Puertas, Kathleen Börner, Javier Martinez-Picado, Barbara Müller, Hans-Georg Kräusslich
• Format: Article
• Language: English
• Published: MDPI AG 2018-11-01
• Series: Viruses
• Subjects: human immunodeficiency virus; primary macrophages; reverse-transcription complex; pre-integration complex; replication kinetics; SAMHD1
• Online Access: https://www.mdpi.com/1999-4915/10/11/620

Macrophages are natural target cells of human immunodeficiency virus type 1 (HIV-1). Viral replication appears to be delayed in these cells compared to lymphocytes; however, little is known about the kinetics of early post-entry events. Time-of-addition experiments using several HIV-1 inhibitors and the detection of reverse transcriptase (RT) products with droplet digital PCR (ddPCR) revealed that early replication was delayed in primary human monocyte-derived macrophages of several donors and peaked late after infection. Direct imaging of reverse-transcription and pre-integration complexes (RTC/PIC) by click-labeling of newly synthesized DNA further confirmed our findings and showed a concomitant shift to the nuclear stage over time. Altering the entry pathway enhanced infectivity but did not affect kinetics of viral replication. The addition of viral protein X (Vpx) enhanced productive infection and accelerated completion of reverse transcription and nuclear entry. We propose that sterile alpha motif (SAM) and histidine/aspartate (HD) domain-containing protein 1 (SAMHD1) activity lowering deoxyribonucleotide triphosphate (dNTP) pools is the principal factor delaying early HIV-1 replication in macrophages.