Multiprotein genetic vaccine in the SIV-Macaca animal model: a promising approach to generate sterilizing immunity to HIV infection.
BACKGROUND
Vaccine combining structural and regulatory proteins is an emerging approach to develop an HIV/AIDS vaccine and therefore, the immunogenicity and efficacy of two regimens of immunization combining structural (Gag/Pol, Env) and regulatory (Rev, Tat, Nef) Simian immunodeficiency virus (SIV) proteins were compared in cynomolgus monkeys.


METHODS
Monkeys were immunized with Modified Vaccine Ankara vector (MVA-J5) (protocol 1) or with DNA, Semliki forest virus and MVA vectors (DNA/SFV/MVA) (protocol 2). At week 32, all monkeys were challenge intravenously (protocol 1) or intrarectally (protocol 2) with 50 MID(50) of SIVmac251. Humoral, proliferative responses and in particular in protocol 2, the frequency of IFN-gamma producing cells, were measured in all monkeys before and after the challenge.


RESULTS
Both vaccine regimens elicited humoral and proliferative responses but failed to induce neutralizing antibodies. Upon intravenous challenge, two out of three MVA-J5 vaccinated monkeys exhibited a long-term control of the viral replication whereas DNA/SFV/MVA vaccine abrogated the virus replication up to undetectable level in three out of four vaccinated monkeys. A major contribution to this vaccine effect appeared to be the IFN-gamma/ELISPOT responses to vaccine antigens (Gag, Rev Tat and Nef).


CONCLUSIONS
These results, indicate that multiprotein heterologous prime-boost vaccination can induce a robust vaccine-induced immunity able to abrogate virus replication.
Division of Experimental Retrovirology and Non-Human Primate Models, National AIDS Center, Istituto Superiore di Sanità, Rome, Italy.
Maria Teresa
MT
Maggiorella
Leonardo
L
Sernicola
Federica
F
Crostarosa
Roberto
R
Belli
Maria Rosaria
MR
Pavone-Cossut
Iole
I
Macchia
Stefania
S
Farcomeni
Klara
K
Tenner-Racz
Paul
P
Racz
Barbara
B
Ensoli
Fausto
F
Titti
D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D049109:Cell Proliferation; D004195:Disease Models, Animal; D005260:Female; D005434:Flow Cytometry / Q000662:veterinary; D007114:Immunization / Q000379:methods / Q000662:veterinary*; D016131:Lymphocyte Subsets / Q000276:immunology / Q000821:virology; D008252:Macaca fascicularis; D008297:Male; D009500:Neutralization Tests / Q000662:veterinary; D018449:SAIDS Vaccines / Q000276:immunology*; D016097:Simian Acquired Immunodeficiency Syndrome / Q000276:immunology* / Q000517:prevention & control / Q000821:virology; D015302:Simian Immunodeficiency Virus / Q000276:immunology*; D019444:Vaccines, DNA / Q000276:immunology*; D019562:Viral Load / Q000662:veterinary
D000914:Antibodies, Viral; D018449:SAIDS Vaccines; D019444:Vaccines, DNA