Oral Abstract Session 01 - Global HIV Vaccine Enterprise

Topic 12: Vaccine Concepts and Design
P12.49
Skin Tattooing as an Effective Tool for Delivering DNA
and Protein Vaccine Immunogens
Y. Chiu 1 , X. Jiang 1 , R. Kumar 2 , C.E. Hioe 3 , S. Zolla-Pazner 3 ,
X. Kong 1
1 NYU School of Medicine, New York, NY, USA; 2 Veterans Affairs
New York Harbor Healthcare System, New York, NY, USA;
3 Departments of Pathology / NYU School of Medicine, New
York, NY, USA
Background: Skin is an excellent site for vaccine administration
due to the abundance of antigen presenting cells and easy
access. When DNA or protein is delivered into the skin, uptake
and expression of immunogens can lead to a rapid and robust
induction of immune responses.Skin tattooing has been
suggested as a useful tool delivering vaccines intradermally. We
have chosen to use the skin tattooing technique to deliver both
DNA and protein immunogens that are focusing the immune
response on the highly immunogenic V3 region of HIV-1 gp120.
Methods: A GFP-containing plasmid was used first to optimize
the protocol for skin tattooing on BALB/c mice. Subsequently,
BALB/c mice were immunized using a DNA prime/Protein boost
regimen. DNA skin tattooing was used first as the prime to
deliver a gp120-encoding DNA plasmid intradermally at weeks
0, 2, and 4. The animals were then given a fusion protein, V3bearing
cholera toxin subunit B (V3-CTB), via skin tattooing
(Group1; n=5) or intramuscular injection (Group2; n=5) at weeks
10 and 14. Two weeks after the final immunization, the sera were
collected and analyzed.
Results: GFP expressed in skin cells was visualized by confocal
microscopy showing that skin tattooing can effectively
deliver DNA into these cells. ELISA assays using sera drawn
after the final immunization confirmed that tattoo-delivered
DNA followed by V3-CTBelicited V3 binding antibodies, and
these antibodies have potent neutralizing activities in an HIV
pseudovirus neutralization assay.
Conclusion: Immunization by skin tattooing is an easy, effective,
and economical way to administer both DNA and protein
vaccines. Interestingly, the needle perforations may serve as a
potent and natural adjuvant for the immunization, making skin
tattooing a promising vaccine delivery technique.
P12.50
AIDS Vaccine 2012
Posters
Different Biological Activity of CD154-SIVgp41 Fusion
Protein Vaccine Component in Naïve or Pre-immune
Individuals
L.M. Smith 1 , L.M. Parodi 1 , V.L. Hodora 1 , L.D. Giavedoni 1
1 Texas Biomedical Research Institute, San Antonio, TX, USA
Background: Trimeric gp41 might be an important target for
neutralizing antibodies; however, the poor immunogenicity of this
region may be due to its lack of exposure on native virus. CD154
(CD40L) is a trimeric glycoprotein found on activated CD4 T-cells
that binds to CD40 on APCs and leads to B-cell activation and
differentiation to plasma cells. We designed a novel immunogen
with the potential for inducing neutralizing antibodies to gp41
and for stimulating activity on APC and B-cells.
Methods: A flexible (FL) and helical (HL) linkers were used to
join CD154 and SIV gp41, which are trimeric glycoproteins
with opposing polarities. Recombinant vaccinia viruses (VVs)
were engineered to express CD154FLgp41 and CD154HLgp41
glycoproteins. PBMCs from SIV naïve and immune macaques were
exposed to wild type VV (VVwt) or to recombinant VVs expressing
SIV Gag, gp160, and Nef (VVgen), or SIV Gag and Nef, and CD154gp41
fusion proteins. Cytokine production and cell activation were
analyzed by Luminex and flow cytometry, respectively.
Results: Both linkers allowed proper protein folding and
CD154 biological activity. Compared to VVwt, VVgen, and
VVCD154FLgp41, PBMCs from naïve macaques exposed to
VVCD154HLgp41 expressed higher levels of IL-6, IL-1Rα, IL-1β,
RANTES, GRO-α, TNF-α, IL-8, IP-10 and IL-10. In contrast, PBMCs
from SIV-immune macaques expressed more IL-6, MIP-1α, MIP-
1β, INF-α, IL-1β, and MCP-1. Interestingly, lymphocytes from
SIV-immune macaques were activated by VVCD154HLgp41 and
VVCD154HLgp41 more than cells exposed to SIVgen.
Conclusion: Fusion proteins of CD154 and gp41 with either HL or
FL assembled into trimers and activated immune cells. However,
there was a differential cytokine expression for the fusion protein
containing the HL, including chemokines that inhibit HIV entry.
This increased biological activity may indicate that the helical
linker allows for a more functional folding of the CD154 moiety.
The CD154HLgp41 fusion protein will be tested in NHP as a novel
vaccine component.
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POSTERS