Repeated DNA therapeutic vaccination of chronically SIV-infected macaques provides additional virological benefit.
We have previously reported that therapeutic immunization by intramuscular injection of optimized plasmid DNAs encoding SIV antigens effectively induces immune responses able to reduce viremia in antiretroviral therapy (ART)-treated SIVmac251-infected Indian rhesus macaques. We subjected such therapeutically immunized macaques to a second round of therapeutic vaccination using a combination of plasmids expressing SIV genes and the IL-15/IL-15 receptor alpha as molecular adjuvant, which were delivered by the more efficacious in vivo constant-current electroporation. A very strong induction of antigen-specific responses to Gag, Env, Nef, and Pol, during ART (1.2-1.6% of SIV-specific T cells in the circulating T lymphocytes) was obtained with the improved vaccination method. Immunological responses were characterized by the production of IFN-gamma, IL-2, and TNF-alpha either alone, or in combination as double or triple cytokine positive multifunctional T cells. A significant induction of CD4(+) T cell responses, mainly targeting Gag, Nef, and Pol, as well as of CD8(+) T cells, mainly targeting Env, was found in both T cells with central memory and effector memory markers. After release from ART, the animals showed a virological benefit with a further approximately 1 log reduction in viremia. Vaccination with plasmid DNAs has several advantages over other vaccine modalities, including the possibility for repeated administration, and was shown to induce potent, efficacious, and long-lasting recall immune responses. Therefore, these data support the concept of adding DNA vaccination to the HAART regimen to boost the HIV-specific immune responses.
Valentin
Antonio
A
Human Retrovirus Section, Vaccine Branch, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702-1201, United States.
von Gegerfelt
Agneta
A
Rosati
Margherita
M
Miteloudis
Georgios
G
Alicea
Candido
C
Bergamaschi
Cristina
C
Jalah
Rashmi
R
Patel
Vainav
V
Khan
Amir S
AS
Draghia-Akli
Ruxandra
R
Pavlakis
George N
GN
Felber
Barbara K
BK
D000276:Adjuvants, Immunologic / Q000494:pharmacology; D000818:Animals; D000956:Antigens, Viral / Q000276:immunology; D023241:Antiretroviral Therapy, Highly Active; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D016207:Cytokines / Q000276:immunology; D018274:Electroporation; D007111:Immunity, Cellular; D056724:Immunity, Humoral; D007117:Immunization, Secondary; D019409:Interleukin-15 / Q000276:immunology; D008253:Macaca mulatta; D010957:Plasmids; D053647:Receptors, Interleukin-15 / Q000276:immunology; D018449:SAIDS Vaccines / Q000276:immunology*; D016097:Simian Acquired Immunodeficiency Syndrome / Q000276:immunology / Q000517:prevention & control*; D019444:Vaccines, DNA / Q000276:immunology*; D019562:Viral Load; D014766:Viremia / Q000276:immunology / Q000517:prevention & control*
D000276:Adjuvants, Immunologic; D000956:Antigens, Viral; D016207:Cytokines; D019409:Interleukin-15; D053647:Receptors, Interleukin-15; D018449:SAIDS Vaccines; D019444:Vaccines, DNA