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Therapy of SHIV-infected Macaques with Antisense DNA of IL-4
Navneet Dhillon*1, S Dhillon1, Y Chebloune1, I Adany1, Z Li1, F Villinger2, O Narayan1, and S Buch1
1Kansas Univ Med Ctr, Kansas City, US and 2Emory Univ, Atlanta, GA, US
Background: Interleukin-4
IIL-4) causes enhancement of replication of HIV strains that utilize the CXCR4
(X4) co-receptor. In this study, we explored the effects of IL-4 antisense DNA
on virus replication and CD8+ T cell responses in lymph nodes
and blood of macaques infected with simian human
immunodeficiency virus (SHIV89.6P).
Methods: We
inoculated 6 animals with SHIV89.6P.
Seven days later, 4 of the animals were given 1mg antisense IL-4 plasmid
complexed with Megafectin liposome intravenously, and 2 of these received a
second injection of the same on day 9. All 6 macaques were killed at 2 weeks post-infection.
Blood from the 6 animals was analyzed for viral RNA concentration in plasma and
CD4 and CD8+ T cells in the mononuclear population (PBMC) on days 7,
10, and 14 post-infection. Real -time polymerase chain reaction (RT-PCR) for
viral gag was used to assess virus in
plasma and in tissues. CD4 and CD8 T cell counts were assessed by flow
cytometery. Immunounohistochemistry was done on paraformaldehyde fixed tissues.
Data were analyzed by using t-tests
or 1-way ANOVA (independent group analysis)
Results: Antisense
IL-4 DNA delivery in SHIV89.6P-infected macaques resulted in a
significant decrease in viral RNA concentrations in the liver, lungs, spleen,
and lymph nodes. Antisense-treated macaques also had a reduction in the
peripheral viral load and this correlated with increased numbers of CD8+
T cells that also expressed higher levels of the CD8+ receptor than
untreated, infected controls. Additionally, lymph node architecture of the
treated animals was better preserved and had increased number of functionally
active and proliferating CD8+ T cells.
Conclusions: This is the
first demonstration of effective SHIV inhibition in targeted macaque tissues by
intravenous injection of cytokine antisense DNA complexed with cationic lipids.
The therapeutic effect of the antisense IL-4 suggests indirectly that the acute
immunosuppressive disease caused by SHIV is mediated, in part, by IL-4, which
causes enhanced virus replication via co-receptor usage, and simultaneously by
suppressing anti-viral CD8 T cell responses.
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