HIV‐1‐specific cell‐mediated immune responses induced by DNA vaccination were enhanced by mannan‐coated liposomes and inhibited by anti‐interferon‐γ antibody

Immunostimulatory DNA sequences (ISS, also known as CpG motifs) are pathogen-associated molecular patterns that are potent stimulators of innate immunity. We tested the ability of ISS to act as an immunostimulatory pathogen-associated molecular pattern in a model HIV vaccine using gp120 envelope protein as the Ag. Mice immunized with gp120 and ISS, or a gp120:ISS conjugate, developed gp120-specific immune responses which included: 1) Ab production; 2) a Th1-biased cytokine response; 3) the secretion of β-chemokines, which are known to inhibit the use of the CCR5 coreceptor by HIV; 4) CTL activity; 5) mucosal immune responses; and 6) CD8 T cell responses that were independent of CD4 T cell help. Based on these results, ISS-based immunization holds promise for the development of an effective preventive and therapeutic HIV vaccine.

Section: Discussionmentioning

confidence: 84%

Immunostimulatory DNA-Based Vaccines Elicit Multifaceted Immune Responses Against HIV at Systemic and Mucosal Sites

Horner¹,

Datta²,

Takabayashi³

et al. 2001

“…pCMVgag was constructed from the gag gene of HIV-1 strain IIIB using the same plasmid vector of pCMV160IIIB plasmid. In addition, a plasmid DNA preparation used in the present study contained liposomes (11).…”

Section: Viral Protein Expression Plasmids and Absmentioning

confidence: 99%

“…into liposomes (11). Briefly, a mixture of 3␤-[NЈ-(NЈ-dimethylaminoethane) carbamoyl] cholesterol and dioleoylphosphatidylethanolamine in chloroform was dried, vacuum desicated, resuspended in sterile HEPES buffer (pH 7.4), and used for the cationic liposomes.…”

Section: Virusmentioning

confidence: 99%

Transplacental Genetic Immunization After Intravenous Delivery of Plasmid DNA to Pregnant Mice

Okuda¹,

Xin²,

Haruki

et al. 2001

A number of factors influence the development of tolerance, including the nature, concentration, and mode of Ag presentation to the immune system, as well as the age of the host. The studies were conducted to determine whether immunizing pregnant mice with liposome-encapsulated DNA vaccines had an effect on the immune status of their offspring. Two different plasmids (encoding Ags from HIV-1 and influenza virus) were administered i.v. to pregnant mice. We examined the uptake of plasmid DNA by the fetuses until the 21st postcoital day, but little such transfer occurred in early pregnancy. At 9.5 days postconception with cationic liposomes, injected plasmid was present in the tissues of the fetus, consistent with transplacental transfer. When the offspring of vaccinated dams were immunized with DNA vaccine, they mounted stronger Ag-specific immune responses than controls, and were protected against challenge by homologous influenza virus after vaccination. Moreover, such immune responses were strong in the offspring of mothers injected with DNA plasmid 9.5 days after coitus. These results suggest that DNA-vaccinated mothers confer the Ag-specific immunity to their progeny.

“…Mannosylation of Ags has been reported to enhance MHC class I-and MHC class II-restricted Ag presentation and T cell stimulation by up to 200-fold compared with nonmannosylated proteins (3)(4)(5)(6)(7). Furthermore, in vivo induction of Th1 cytokines and Ag-specific CTL responses were observed in mice upon immunization with mannosylated vaccines (6,8,9). Thus, Ag mannosylation is an attractive strategy for boosting cell-mediated immune responses.…”

mentioning

confidence: 99%

A Model Vaccine Exploiting Fungal Mannosylation to Increase Antigen Immunogenicity

Lam

Mansour

Specht

et al. 2005

100

Ag mannosylation represents a promising strategy to augment vaccine immunogenicity by targeting Ag to mannose receptors (MRs) on dendritic cells. Because fungi naturally mannosylate proteins, we hypothesized that Ags engineered in fungi would have an enhanced capacity to stimulate T cell responses. Using the model Ag OVA, we generated proteins that differentially expressed N- and O-linked mannosylation in the yeast Pichia pastoris and compared them to their unglycosylated counterparts produced in Escherichia coli. We found that yeast-derived OVA proteins containing N-linkages, extensive O-linkages, or both were more potent than the unmannosylated Ags at inducing OVA-specific CD4+ T cell proliferation. This elevated response to fungal Ags was inhibited by mannan, suggesting involvement of MRs. However, the macrophage MR (CD206) was not essential, because macrophage MR-deficient dendritic cells were fully competent in presenting yeast-derived OVA Ags. Thus, the use of fungal glycosylation to provide N-linked and/or extensive O-linked mannosylation increased the capacity of the model Ag OVA to stimulate Ag-specific T cell responses in an MR-dependent manner. These data have implications for vaccine design by providing proof of principle that yeast-derived mannosylation can enhance immunogenicity.