EVOLUTION: Of Mice . . .

Background Approximately 20 percent of adults become infected with human papillomavirus type 16 (HPV-16). Although most infections are benign, some progress to anogenital cancer. A vaccine that reduces the incidence of HPV-16 infection may provide important public health benefits. Methods In this double-blind study, we randomly assigned 2392 young women (defined as females 16 to 23 years of age) to receive three doses of placebo or HPV-16 virus-like–particle vaccine (40 μg per dose), given at day 0, month 2, and month 6. Genital samples to test for HPV-16 DNA were obtained at enrollment, one month after the third vaccination, and every six months thereafter. Women were referred for colposcopy according to a protocol. Biopsy tissue was evaluated for cervical intraepithelial neoplasia and analyzed for HPV-16 DNA with use of the polymerase chain reaction. The primary end point was persistent HPV-16 infection, defined as the detection of HPV-16 DNA in samples obtained at two or more visits. The primary analys...

A controlled trial of a human papillomavirus type 16 vaccine.

Innate immunity: impact on the adaptive immune response

A surgical clip applier includes a housing, a pair of handles pivotably connected to opposite sides of the housing, a channel assembly which is anchored to the housing and a jaw assembly which is anchored to the channel assembly. The jaws are opened and closed by a cam plate which is slidably positioned in the channel assembly and is provided with cam slots at its distal end to engage drive rivets positioned on the jaw members. A pusher bar assembly is also provided to feed clips from a series of clips to the jaw mechanism, and the instrument operates such that all moving components move in the same direction during the closing stroke of the handle, and then move in the same direction opposite to the closing direction when the handles are in the opening stroke. A novel lockout mechanism is also provided to render the instrument inoperable after all the clips have been utilized from the instrument.

Surgical clip applier

Recent advances in wet chemical synthesis and biomolecular functionalization of gold nanoparticles have led to a dramatic expansion of their potential biomedical applications, including biosensorics, bioimaging, photothermal therapy, and targeted drug delivery. As the range of gold nanoparticle types and their applications continues to increase, human safety concerns are gaining attention, which makes it necessary to better understand the potential toxicity hazards of these novel materials. Whereas about 80 reports on the in vivo biodistribution and in vitrocell toxicity of gold nanoparticles are available in the literature, there is lack of correlation between both fields and there is no clear understanding of intrinsic nanoparticle effects. At present, the major obstacle is the significant discrepancy in experimental conditions under which biodistribution and toxicity effects have been evaluated. This critical review presents a detailed analysis of data on the in vitro and in vivo biodistribution and toxicity of most popular gold nanoparticles, including atomic clusters and colloidal particles of diameters from 1 to 200 nm, gold nanoshells, nanorods, and nanowires. Emphasis is placed on the systematization of data over particle types and parameters, particle surface functionalization, animal and cell models, organs examined, doses applied, the type of particle administration and the time of examination, assays for evaluating gold particle toxicity, and methods for determining the gold concentration in organs and distribution of particles over cells. On the basis of a critical analysis of data, we arrive at some general conclusions on key nanoparticle parameters, methods of particle surface modification, and doses administered that determine the type and kinetics of biodistribution and toxicity at cellular and organismal levels (197 references).

Biodistribution and toxicity of engineered gold nanoparticles: a review of in vitro and in vivo studies

Cytotoxic T lymphocytes (CTLs) specific for conserved viral antigens can respond to different strains of virus, in contrast to antibodies, which are generally strain-specific. The generation of such CTLs in vivo usually requires endogenous expression of the antigen, as occurs in the case of virus infection. To generate a viral antigen for presentation to the immune system without the limitations of direct peptide delivery or viral vectors, plasmid DNA encoding influenza A nucleoprotein was injected into the quadriceps of BALB/c mice. This resulted in the generation of nucleoprotein-specific CTLs and protection from a subsequent challenge with a heterologous strain of influenza A virus, as measured by decreased viral lung titers, inhibition of mass loss, and increased survival.

https://science.sciencemag.org/content/sci/259/5102/1745.full.pdf

Heterologous protection against influenza by injection of DNA encoding a viral protein

In the years following the publication of the initial in vivo demonstration of the ability of plasmid DNA to generate protective immune responses, DNA vaccines have entered into a variety of human clinical trials for vaccines against various infectious diseases and for therapies against cancer, and are in development for therapies against autoimmune diseases and allergy. They also have become a widely used laboratory tool for a variety of applications ranging from proteomics to understanding Ag presentation and cross-priming. Despite their rapid and widespread development and the commonplace usage of the term "DNA vaccines," however, the disappointing potency of the DNA vaccines in humans underscores the challenges encountered in the efforts to translate efficacy in preclinical models into clinical realities. This review will provide a brief background of DNA vaccines including the insights gained about the varied immunological mechanisms that play a role in their ability to generate immune responses.

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DNA Vaccines: Progress and Challenges

Vaccination with plasmid DNA expression vectors encoding foreign proteins elicits antibodies and cell-mediated immunity and protects against disease in animal models. We report a comparison of DNA vaccines, using contemporary human strains of virus, and clinically licensed (inactivated virus or subvirion) vaccines in preclinical animal models, to better predict their efficacy in humans. Influenza DNA vaccines elicited antibodies in both non-human primates and ferrets and protected ferrets against challenge with an antigenically distinct epidemic human influenza virus more effectively than the contemporary clinically licensed vaccine. These studies demonstrate that DNA vaccines may be more effective, particularly against different strains of virus, than inactivated virus or subvirion vaccines.

Preclinical efficacy of a prototype DNA vaccine: Enhanced protection against antigenic drift in influenza virus

We have recently shown that direct injection of DNA can be an effective vaccine strategy eliciting both humoral and cell-mediated immune responses Vectors were designed specifically for vaccination by direct DNA injection and refined to improve plasmid production in Escherichia coli The vectors consist of a pUC-19 backbone with the cytomegalovirus (CMV) IE1 enhancer, promoter, and intron A transcription regulatory elements and the BGH polyadenylation sequences driving the expression of the reporter gene CAT or influenza A nucleoprotein (NP) or hemagglutinin (HA) The respective vectors expressed high levels of chloramphenicol acetyltransferase (CAT) and NP in tissue culture, and yielded 14-15 mg of purified plasmid per liter of Escherichia coli culture Immunization of mice with the NP and HA expression vectors resulted in protection from subsequent lethal challenges of influenza using either heterologous or homologous strains, respectively

Heterologous and Homologous Protection Against Influenza A by DNA Vaccination: Optimization of DNA Vectors

Intramuscular injection of DNA vaccines elicits potent humoral and cellular immune responses in mice. However, DNA vaccines are less efficient in larger animal models and humans. To gain a better understanding of the factors limiting the efficacy of DNA vaccines, we used fluorescence-labeled plasmid DNA in mice to 1) define the macroscopic and microscopic distribution of DNA after injection into the tibialis anterior muscle, 2) characterize cellular uptake and expression of DNA in muscle and draining lymph nodes, and 3) determine the effect of modifying DNA distribution and cellular uptake by volume changes or electroporation on the magnitude of the immune response. Injection of a standard 50-μl dose resulted in the rapid dispersion of labeled DNA throughout the muscle. DNA was internalized within 5 min by muscle cells near the injection site and over several hours by cells that were located along muscle fibers and in the draining lymph nodes. Histochemical staining and analysis of mRNA expression in isolated cells by RT-PCR showed that the transgene was detectably expressed only by muscle cells, despite substantial DNA uptake by non-muscle cells. Reduction of the injection volume to 5 μl resulted in substantially less uptake and expression of DNA by muscle cells, and correspondingly lower immune responses against the transgene product. However, expression and immunogenicity were restored when the 5-μl injection was followed by electroporation in vivo. These findings indicate that distribution and cellular uptake significantly affect the immunogenicity of DNA vaccines.

John J. Donnelly

Papers

Heterologous protection against influenza by injection of DNA encoding a viral protein

DNA Vaccines: Progress and Challenges

Preclinical efficacy of a prototype DNA vaccine: Enhanced protection against antigenic drift in influenza virus

Heterologous and Homologous Protection Against Influenza A by DNA Vaccination: Optimization of DNA Vectors

Distribution of DNA vaccines determines their immunogenicity after intramuscular injection in mice.