Oral Abstract Session 01 - Global HIV Vaccine Enterprise

Topic 12: Vaccine Concepts and Design
P12.65 LB
Liposomal Formulation of Gp41 Derivate with
Adjuvant MPLA: Vaccine Design, Immunogenicity in
Animals and Safety in Humans
D. Katinger 1 , A. Wagner 1 , I. Luque 2 , S. Crespillo 2 , F. Conejero-
Lara 2 , M. Roger 3 , C. Martin 3 , N. Mouz 3 , S. Mourao 4 , A. Farsang 5 ,
F. Notka 6 , K. Malcolm 7 , N. Bosquet 8 , R. Le Grand 8 , C. Moog 9 ,
A. Cope 10 , R. Shattock 10 , D.J. Lewis 11 , R. El Habib 12
1 Polymun Scientific GmbH, Klosterneuburg, Austria;
2 Universidad de Granada, Granada, Spain; 3 PX’Therapeutics,
Grenoble, France; 4 I.M. PROJET, Miribel, France; 5 National
Food Chain Safety Office, Budapest, Hungary; 6 GeneArt AG /
Life Technologies, Regensburg, Germany; 7 Queen’s University
of Belfast, Belfast, United Kingdom (Great Britain); 8 CEA,
Fontenay-aux-Roses, France; 9 Université de Strasbourg,
Strasbourg, France; 10 Imperial College, London, United
Kingdom (Great Britain); 11 University of Surrey, Guildford,
United Kingdom (Great Britain); 12 Sanofi Pasteur, Marcy
l’Etoile, France
Background: Gp41 of the HIV envelope, especially the MPER,
contains highly conserved epitopes recognized by neutralizing
monoclonal antibodies such as D5, 2F5 and 4E10. The correct
presentation of the antigens is considered to be key for eliciting
neutralizing immune response. The lipid bilayer of liposomes can
mimic the virus surface and therefore provides the appropriate
presentation of this membrane protein. In addition, liposomes
can integrate the adjuvant monophosphoryl lipid A (MPLA).
Methods: The gp41 derivate FPA2 was mutated to increase its
solubility and modify its structure for exposure of neutralizing
epitopes. The protein was expressed in E. coli. The purified
protein was solubilized with detergent. Liposomes were prepared
containing antigen FPA2 and MPLA, a Toll-like receptor 4 agonist,
using a continuous ethanol crossflow injection technology.
Immunogenicity and safety was determined in rabbits and
macaques. The liposomes formulated in HEC gel were applied
i.n. followed by two intramuscular boosts in healthy female
volunteers in a phase I study of safety and immunogenicity.
Results: Liposomes containing FPA2 and MPLA manufactured
under GMP conditions were uniform and stable at 2-8°C.
Immunogenicity was demonstrated in rabbits and monkey after
mucosal (i.vag., i.n.) prime, followed by intramuscular boosts.
Immune response was induced systemically and in mucosal
surfaces. Preliminary data from the clinical phase 1 study in
healthy volunteers demonstrated good safety with three nasal
applications of 200 µg of the formulated protein in HEC gel and
of two i.m. boosts.
Conclusion: The liposomal formulation of the gp41 subunit
of HIV envelope together with MPLA as adjuvant proved to be
well tolerated in animals and human. Liposome-formulated
FPA2 was able to induce binding antibodies measured by ELISA
and neutralizing activity in both blood and vaginal secretions in
animals. Immunogenicity testing in humans is ongoing.
P12.66 LB
AIDS Vaccine 2012
Posters
Novel AIDS Vaccine Approach using Epithelial Stem
Cells as Mucosal Antigen-Presenting Cells
G. Bonello 1 , N. Chenciner 2 , R. White 1 , M. Salas 1 , P. Blancou 3 ,
M. Gauduin 1
1Texas Biomedical Research Institute, San Antonio, TX, USA;
2 3 Institut Pasteur, Paris, France; Universitée de Nantes, Nantes,
France
Background: Because HIV transmission occurs predominantly
across mucosal surfaces, the ideal vaccine strategy to prevent
infection would be to target HIV at mucosal entry sites of
transmission. We investigated a novel vaccine approach, which
aim is to elicit long-term immunity against HIV infection at the
entry site of the virus. This strategy relies on the expression of
viral proteins from epithelial stem cells at the basal layer of the
epithelium and using a promoter that is specific for terminally
differentiated epithelial
Methods: The involucrin promoter, which is exclusively
expressed in terminally differentiated epithelial cells, was chosen
and used as a tool. We generated a GFP-tagged replication
competent SIVdeltaNef and a GFP-tagged replication deficient
SIVdeltaVifdeltaNef constructs under the transcriptional control
of the involucrin promoter (pINV). Viral stocks used to deliver
these constructs to basal epithelial cells were obtained by their
co-transfection with a plasmid encoding for VSV-G envelope
proteins used as pseudotyping envelope protein of significantly
broadened host cell range.
Results: When administered intradermally to mice, we found
that GFP-reporter gene under the transcriptional control of
the involucrin promoter was expressed in the upper layers
of the epidermis. Although transduced cells were very low in
number, high and sustained anti-GFP antibody production was
observed in vivo. After production of high concentrations of
infectious viral particles, we demonstrated the integrity of our
constructs (regions encoding for GAG, POL and GFP) in the
VSV-G pseudotyped viral particles to be used for inoculation in
nonhuman primate model for AIDS.
Conclusion: After integration of pINV-driven constructs, basal
layer cells will divide and differentiate thus triggering SIV antigens
expression as well as both direct and cross priming. Long-term
antigen expression in upper layers of the epithelium may occur
even after multiple cycles of epithelia renewal, thus eliciting a
long-term immunity against HIV/SIV infection at the site
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POSTERS