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153 Transient HIV-1 Infection in Sooty Mangabey and Pig-Tailed Macaque Cells: Lack of Viral Integration?
S. Owen*1, S. Masciotra1, H. McClure2, F. Novembre2, and R. Lal1
1 CDC, Atlanta, GA, USA and 2Yerkes Primate Ctr., Emory Univ., Atlanta, GA, USA
Background: Most vaccine studies use SHIV constructs that do not fully represent a natural HIV-1 infection. The focus of this study is to characterize HIV-1 replication in macaque and mangabey cells (MMC) and improve upon existing nonhuman primate (NHP) models by either adapting HIV-1 to infect MMC or by generating a chimeric HIV-1 /HIV-2 construct that is capable of replication in MMC.
Methods: Primary HIV-1 isolates with broad coreceptor specificities and LAI were used to infect CD8 depleted PHA-blasted MMC. PCR was used to detect viral entry (RU5 primers), late reverse transcription (protease primers), and integration (Alu-LTR, LTR primers). Antigen production was monitored using a p24 ELISA (Coulter). Additionally, HIV-1 from MMC was concentrated and passaged on MMC and human cells. Coinfection experiments with the HIV-2 isolate CDC77618, which replicates in MMC, were conducted to ascertain the ability of HIV-2 genes to complement HIV-1 infection.
Results: Four HIV-1 isolates including LAI consistently resulted in transient production of p24 in MMC with peak values generally observed between 3 and 6 days post-virus addition. PCR analysis of DNA from MMC confirmed viral entry (RU5 products) and reverse transcription (protease products). However, no integrated provirus was detected using a highly sensitive Alu-LTR PCR. Concentrated HIV-1 from the MMC was infectious to human PBMCs but not to MMC. Furthermore, HIV-1 replication was not complemented in the coinfection experiments with CDC77618.
Conclusions: Our data indicate HIV-1 is capable of entry and reverse transcription in MMC. Additionally, these data suggest a block to HIV-1 productive infection in MMC is due to the inability of HIV-1 to integrate into the cellular genome. Furthermore, the transient production of viral particles from MMC that are infectious to human PBMCs but not MMC indicates a need for a species-specific factor in the production of infectious HIV-1. Complementation experiments with clones expressing HIV-2 genes (CDC77618) equivalent to the SIV genes found in SHIV constructs and production of recombinant HIV-1/HIV-2 constructs are underway to better understand the requirements for HIV-1 replication in MMC.
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