DNA vaccination by intradermal electroporation induces long-lasting immune responses in rhesus macaques.

Background: A desirable HIV vaccine should induce protective long-lasting humoral and cellular immune responses.

Methods: Macaques were immunized by env DNA, selected from a panel of recently transmitted SIVmac251 Env using intradermal electroporation as vaccine delivery method and magnitude, breadth and longevity of humoral and cellular immune responses.

Results: The macaques developed high, long-lasting humoral immune responses with neutralizing capacity against homologous and heterologous Env.

In vivo electroporation and non-protein based screening assays to identify antibodies against native protein conformations.

In vivo electroporation has become a gold standard method for DNA immunization. The method assists the DNA entry into cells, results in expression and the display of the native form of antigens to professional cells of the immune system, uses both arms of immune system, has a built-in adjuvant system, is relatively safe, and is cost-effective. However, there are challenges for achieving an optimized reproducible process for eliciting strong humoral responses and for the screening of specific immune responses, in particular, when the aim is to mount humoral responses or to generate monoclonal antibodies via hybridoma technology.

Biodistribution, persistence and lack of integration of a multigene HIV vaccine delivered by needle-free intradermal injection and electroporation.

It is likely that gene-based vaccines will enter the human vaccine area soon. A few veterinary vaccines employing this concept have already been licensed, and a multitude of clinical trials against infectious diseases or different forms of cancer are ongoing. Highly important when developing novel vaccines are the safety aspects and also new adjuvants and delivery techniques needs to be carefully investigated so that they meet all short- and long-term safety requirements.

Optimization of skin electroporation in mice to increase tolerability of DNA vaccine delivery to patients.

Electroporation has, during the last years, proven to be a very successful delivery method for DNA vaccines and has now reached clinical evaluation. Although intramuscular electroporation is practical in animal models, intradermal electroporation might be more suitable for clinical administration. Skin is the most accessible organ of the body and has professional antigen-presenting cells in large amounts; thus, skin is an ideal target for DNA vaccine delivery.

Smallpox DNA vaccine delivered by novel skin electroporation device protects mice against intranasal poxvirus challenge.

Previously, we demonstrated that an experimental smallpox DNA vaccine comprised of four vaccinia virus genes (4pox) administered by gene gun elicited protective immunity in mice challenged with vaccinia virus, and in nonhuman primates challenged with monkeypox virus (Hooper JW, et al. Smallpox DNA vaccine protects nonhuman primates against lethal monkeypox. J Virol 2004;78:4433-43).

High efficiency gene delivery into laryngeal muscle with bidirectional electroporation.

Objective: The impact of polarity change on the efficiency of in vivo electroporative (EP) gene transfection was assessed in rat laryngeal muscle.

Study Design And Setting: High (HV) and low field voltage (LV) were combined with polarity changes to determine transfection in 5 different conditions: 1) without EP (EP[-]), 2) HV+LV (HL), 3) HV+LV followed by HV+LV with no change in polarity (HLHL unidirectional), 4) HV+LV followed by HV+LV with opposite polarity (HLHL bidirectional), 5) HV+LV followed by LV with opposite polarity (HLL bidirectional).

Results: HLL bidirectional sequence showed the best result with less interindividual variability and extended expression period.

Generation of dendritic cell-tumor cell hybrids by electrofusion for clinical vaccine application.

Vaccination with hybrids comprising fused dendritic cells (DCs) and tumor cells is a novel cancer immunotherapy approach designed to combine tumor antigenicity with the antigen-presenting and immune-stimulatory capacities of DCs. For clinical purposes, we have incorporated a large-scale process for the generation of clinical-grade DCs together with novel electrofusion technology. The electrofusion system provides for ease and standardization of method, efficient DC-tumor cell hybrid formation, and large-quantity production of hybrids in a high-volume (6-ml) electrofusion chamber.

Serotype-specific T(H)1 responses in recipients of two doses of candidate live-attenuated dengue virus vaccines.

As part of a larger vaccine study, peripheral blood mononuclear cells (PBMC) were collected from volunteers for analysis of vaccine-induced T cell responses. The PBMC were re-stimulated in vitro with live dengue virus and assayed for T(H)1 or T(H)2 memory cell responses. Re-stimulated PBMC from the volunteers predominantly secreted interferon-gamma.

Vaccination of human volunteers with monovalent and tetravalent live-attenuated dengue vaccine candidates.

Four serotypes of monovalent live attenuated dengue virus vaccine candidates were tested for reactogenicity and immunogenicity in 49 flavivirus non-immune adult human volunteers. The four monovalent candidates were then combined into a tetravalent formulation and given to another 10 volunteers. Neutralizing antibody seroconversion rates after a single-dose monovalent vaccination ranged from 53% to 100%.