Type III and I interferons increase HIV uptake and replication in human cells, that overexpress CD4, CCR5 and CXCR4

The newly discovered type III interferon (IFN-) has antiviral activity against a broad spectrum of viruses
and potent immune-related activities. Its major producers are peripheral blood mononuclear cells (PBMCs)
and dendritic cells. The above functions and cells are deeply involved in AIDS pathogenesis, but there is no
information so far on IFN- effects on HIV. Therefore we addressed the sensitivity of HIV-1 replication to
cell exposure to human IFN-2. Human PBMCs and C8166 T cells were treated with human Type III or Type
I IFNs, and the ability of HIV-1 to bind and replicate in untreated and IFN-treated cells was investigated.
Virus amounts were quantified by infectivity and p24 assays. In parallel, we evaluated the possible antiproliferative
effects of IFN-2 and the expression of CD4, CXCR4, and CCR5 genes, whose transcripts were
quantified by real time RT-PCR. Data showed increased adsorption of HIV to IFN-treated cells in a dose-dependent
fashion. Virus yields increased accordingly. In both systems the accumulation of CD4, CXCR4, and
CCR5 transcripts was increased, particularly in PBMCs. Antiproliferative activity and classical antiviral state
were instead detected on PBMCs, but not on C8166 cells. We concluded that pretreatment of PBMCs and
C8166 cells with Type III and Type I IFNs causes increased HIV binding and replication. These effects are
likely to be due to increased expression of HIV receptors and coreceptors on the plasma membrane. These
findings indicate another mechanism utilized by HIV for subversion of host defenses