IL-12 DNA as molecular vaccine adjuvant increases the cytotoxic T cell responses and breadth of humoral immune responses in SIV DNA vaccinated macaques.
Intramuscular injection of macaques with an IL-12 expression plasmid (0.1 or 0.4 mg DNA/animal) optimized for high level of expression and delivered using in vivo electroporation, resulted in the detection of systemic IL-12 cytokine in the plasma. Peak levels obtained by day 4-5 post injection were paralleled by a rapid increase of IFN-γ, indicating bioactivity of the IL-12 cytokine. Both plasma IL-12 and IFN-γ levels were reduced to basal levels by day 14, indicating a short presence of elevated levels of the bioactive IL-12. The effect of IL-12 as adjuvant together with an SIVmac239 DNA vaccine was further examined comparing two groups of rhesus macaques vaccinated in the presence or absence of IL-12 DNA. The IL-12 DNA-adjuvanted group developed significantly higher SIV-specific cellular immune responses, including IFN-γ (+) Granzyme B (+) T cells, demonstrating increased levels of vaccine-induced T cells with cytotoxic potential, and this difference persisted for 6 mo after the last vaccination. Coinjection of IL-12 DNA led to increases in Gag-specific CD4 (+) and CD4 (+) CD8 (+) double-positive memory T cell subsets, whereas the Env-specific increases were mainly mediated by the CD8 (+) and CD4 (+) CD8 (+) double-positive memory T cell subsets. The IL-12 DNA-adjuvanted vaccine group developed higher binding antibody titers to Gag and mac251 Env, and showed higher and more durable neutralizing antibodies to heterologous SIVsmE660. Therefore, co-delivery of IL-12 DNA with the SIV DNA vaccine enhanced the magnitude and breadth of immune responses in immunized rhesus macaques, and supports the inclusion of IL-12 DNA as vaccine adjuvant.
Human Retrovirus Pathogenesis Section; Frederick National Laboratory for Cancer Research, Frederick, MD, USA.
Rashmi
R
Jalah
Vainav
V
Patel
Viraj
V
Kulkarni
Margherita
M
Rosati
Candido
C
Alicea
Brunda
B
Ganneru
Agneta
A
von Gegerfelt
Wensheng
W
Huang
Yongjun
Y
Guan
Kate E
KE
Broderick
Niranjan Y
NY
Sardesai
Celia
C
LaBranche
David C
DC
Montefiori
George N
GN
Pavlakis
Barbara K
BK
Felber
D000276:Adjuvants, Immunologic; D000818:Animals; D018274:Electroporation; D056724:Immunity, Humoral / Q000276:immunology*; D018664:Interleukin-12 / Q000097:blood / Q000235:genetics*; D008251:Macaca; D008253:Macaca mulatta; D018449:SAIDS Vaccines / Q000276:immunology; D015302:Simian Immunodeficiency Virus / Q000276:immunology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D019444:Vaccines, DNA / Q000276:immunology
D000276:Adjuvants, Immunologic; D018449:SAIDS Vaccines; D019444:Vaccines, DNA; D018664:Interleukin-12