In silico evidences of Mpro inhibition by a series of organochalcogen-AZT derivatives and their safety in Caenorhabditis elegans.

BACKGROUND: The new coronavirus (SARS-CoV-2) pandemic emerged in 2019 causing millions of deaths. Vaccines were quickly developed and made available in 2021. Despite the availability of vaccines, some subjects refuse to take the immunizing or present comorbities, therefore developing serious cases of COVID-19, which makes necessary the development of antiviral drugs. Previous studies have demonstrated that ebselen, a selenium-containing molecule, can inhibit SARS-CoV-2 Mpro. In addition, selenium is a trace element that has antiviral and anti-inflammatory properties. Zidovudine (AZT) has been widely used against HIV infections and its action against SARS-CoV-2 may be altered by the structural modification with organochalcogen moieties, but this hypothesis still needs to be tested. METHODS: In the present work we evaluated the Mpro inhibition capacity (in silico), the safety and antioxidant effect of six organochalcogen AZT-derivatives using the free-living nematode Caenorhabditis elegans, through acute (30 min) and chronic (48) exposure protocols. RESULTS: We observed that the molecules were safe at a concentration range of 1-500 µM and did not alter any toxicological endpoint evaluated. Furthermore, the molecules are capable to decrease the ROS formation stimulated by hydrogen peroxide, to modulate the expression of important antioxidant enzymes such superoxide-dismutase-3 and glutathione S-transferese-4 and to stimulate the translocation of the DAF-16 to the cell nucleus. In addition, the molecules did not deplete thiol groups, which reinforces their safety and contribution to oxidative stress resistance. CONCLUSIONS: We have found that compounds S116l (a Tellurium AZT-derivative) and S116h (a Selenium-AZT derivative) presented more promising effects both in silico and in vivo, being strong candidates for further in vivo studies.

Effects of maternal gestational diet, with or without methionine, on muscle transcriptome of Bos indicus-influenced beef calves following a vaccine-induced immunological challenge.

Maternal nutrition during gestation can cause epigenetic effects that translate to alterations in gene expression in offspring. This 2-year study employed RNA-sequencing technology to evaluate the pre- and post-vaccination muscle transcriptome of early-weaned Bos indicus-influenced beef calves born from dams offered different supplementation strategies from 57 ± 5 d prepartum until 17 ± 5 d postpartum. Seventy-two Brangus heifers (36 heifers/yr) were stratified by body weight and body condition score and assigned to bahiagrass pastures (3 heifers/pasture/yr). Treatments were randomly assigned to pastures and consisted of (i) no pre- or postpartum supplementation (NOSUP), (ii) pre- and postpartum supplementation of protein and energy using 7.2 kg of dry matter/heifer/wk of molasses + urea (MOL), or (iii) MOL fortified with 105 g/heifer/wk of methionine hydroxy analog (MOLMET). Calves were weaned on d 147 of the study. On d 154, 24 calves/yr (8 calves/treatment) were randomly selected and individually limit-fed a high-concentrate diet until d 201. Calves were vaccinated on d 160. Muscle biopsies were collected from the same calves (4 calves/treatment/day/yr) on d 154 (pre-vaccination) and 201 (post-vaccination) for gene expression analysis using RNA sequencing. Molasses maternal supplementation led to a downregulation of genes associated with muscle cell differentiation and development along with intracellular signaling pathways (e.g., Wnt and TGF-ß signaling pathway) compared to no maternal supplementation. Maternal fortification with methionine altered functional gene-sets involved in amino acid transport and metabolism and the one-carbon cycle. In addition, muscle transcriptome was impacted by vaccination with a total of 2,396 differentially expressed genes (FDR ≤ 0.05) on d 201 vs. d 154. Genes involved in cell cycle progression, extracellular matrix, and collagen formation were upregulated after vaccination. This study demonstrated that maternal supplementation of energy and protein, with or without, methionine has long-term implications on the muscle transcriptome of offspring and potentially influence postnatal muscle development.

Development of anti-thrombotic vaccine against human S100A9 in rhesus monkey.

In post-stroke patients, a decreased adherence to antiplatelet drugs is a major challenge in the prevention of recurrent stroke. Previously, we reported an antiplatelet vaccine against S100A9 in mice, but the use of Freund's adjuvant and the difference in amino acid sequences in epitopes between mice and humans were problematic for clinical use. Here, we redesigned the S100A9 vaccine for the common sequence in both humans and monkeys and examined its effects in cynomolgus monkeys with Alum adjuvant. First, we assessed several candidate epitopes and selected 102 to 112 amino acids as the suitable epitope, which could produce antibodies. When this peptide vaccine was intradermally injected into 4 cynomolgus monkeys with Alum, the antibody against human S100A9 was successfully produced. Anti-thrombotic effects were shown in two monkeys in a mixture of vaccinated serum and fresh whole blood from another cynomolgus monkey. Additionally, the anti-thrombotic effects were partially inhibited by the epitope peptide, indicating the feasibility of neutralizing anti-thrombotic effects of produced antibodies. Prolongation of bleeding time was not observed in vaccinated monkeys. Although further studies on increasing the effect of vaccine and safety are necessary, this vaccine will be a promising approach to improve adherence to antiplatelet drugs in clinical settings.

Transversal gene expression panel to evaluate intestinal health in broiler chickens in different challenging conditions.

There is a high interest on gut health in poultry with special focus on consequences of the intestinal diseases, such as coccidiosis and C. perfringens-induced necrotic enteritis (NE). We developed a custom gene expression panel, which could provide a snapshot of gene expression variation under challenging conditions. Ileum gene expression studies were performed through high throughput reverse transcription quantitative real-time polymerase chain reaction. A deep review on the bibliography was done and genes related to intestinal health were selected for barrier function, immune response, oxidation, digestive hormones, nutrient transport, and metabolism. The panel was firstly tested by using a nutritional/Clostridium perfringens model of intestinal barrier failure (induced using commercial reused litter and wheat-based diets without exogenous supplementation of enzymes) and the consistency of results was evaluated by another experiment under a coccidiosis challenge (orally gavaged with a commercial coccidiosis vaccine, 90× vaccine dose). Growth traits and intestinal morphological analysis were performed to check the gut barrier failure occurrence. Results of ileum gene expression showed a higher expression in genes involved in barrier function and nutrient transport in chickens raised in healthy conditions, while genes involved in immune response presented higher expression in C.perfringens-challenged birds. On the other hand, the Eimeria challenge also altered the expression of genes related to barrier function and metabolism, and increased the expression of genes related to immune response and oxidative stress. The panel developed in the current study gives us an overview of genes and pathways involved in broiler response to pathogen challenge. It also allows us to deep into the study of differences in gene expression pattern and magnitude of responses under either a coccidial vaccine or a NE.

Poly(amino acids) as a potent self-adjuvanting delivery system for peptide-based nanovaccines.

To be optimally effective, peptide-based vaccines need to be administered with adjuvants. Many currently available adjuvants are toxic, not biodegradable; they invariably invoke adverse reactions, including allergic responses and excessive inflammation. A nontoxic, biodegradable, biocompatible, self-adjuvanting vaccine delivery system is urgently needed. Herein, we report a potent vaccine delivery system fulfilling the above requirements. A peptide antigen was coupled with poly-hydrophobic amino acid sequences serving as self-adjuvanting moieties using solid-phase synthesis, to produce fully defined single molecular entities. Under aqueous conditions, these molecules self-assembled into distinct nanoparticles and chain-like aggregates. Following subcutaneous immunization in mice, these particles successfully induced opsonic epitope-specific antibodies without the need of external adjuvant. Mice immunized with entities bearing 15 leucine residues were able to clear bacterial load from target organs without triggering the release of soluble inflammatory mediators. Thus, we have developed a well-defined and effective self-adjuvanting delivery system for peptide antigens.

Current prevention and potential treatment options for dengue infection.

Currently, treatments for dengue infection are only symptomatic as no antiviral agents nor vaccines are available to combat this virus. Despite challenges faced by researchers, many efforts are ongoing to reduce cases of dengue infection either by targeting the vector or the virus. Vector population is monitored and reduced by using mechanical, chemical and biological controls. Chemical control is achieved either by using synthetic or natural insecticides where the latter is more preferable. In biological control, bacteria, fungi and larvivorous fish are utilised to reduce the vector population. Moreover, genes of mosquitoes are also explored to produce progenies which are sterile with low survival ability. Vaccines are among the most effective ways to prevent viral infection. Various approaches have been used and are still being explored towards producing vaccines for dengue. These include live attenuated, inactivated, recombinant subunit, nucleic acid and virus-like particles vaccines. The aim is to produce a vaccine which can target all the four serotypes of the virus. Monoclonal antibodies are widely researched on to equip the host defense mechanism against the dengue virus. Deeper understanding of the virus replication cycle warrants the development of antiviral agents which target viral proteins vital for the replication process. Bioactive compounds are also utilised in the development of antiviral agents. The importance of surveillance and supportive therapy are also discussed.

Gel Phase 1,2-Distearoyl-sn-glycero-3-phosphocholine-Based Liposomes Are Superior to Fluid Phase Liposomes at Augmenting Both Antigen Presentation on Major Histocompatibility Complex Class II and Costimulatory Molecule Display by Dendritic Cells in Vitro.

Lipid-based nanoparticles have in recent years attracted increasing attention as pharmaceutical carriers. In particular, reports of them having inherent adjuvant properties combined with their ability to protect antigen from degradation make them suitable as vaccine vectors. However, the physicochemical profile of an ideal nanoparticle for vaccine delivery is still poorly defined. Here, we used an in vitro dendritic cell assay to assess the immunogenicity of a variety of liposome formulations as vaccine carriers and adjuvants. Using flow cytometry, we investigated liposome-assisted antigen presentation as well as the expression of relevant costimulatory molecules on the cell surface. Cytokine secretion was further evaluated with an enzyme-linked immunosorbent assay (ELISA). We show that liposomes can successfully enhance antigen presentation and maturation of dendritic cells, as compared to vaccine fusion protein (CTA1-3Eα-DD) administered alone. In particular, the lipid phase state of the membrane was found to greatly influence the vaccine antigen processing by dendritic cells. As compared to their fluid phase counterparts, gel phase liposomes were more efficient at improving antigen presentation. They were also superior at upregulating the costimulatory molecules CD80 and CD86 as well as increasing the release of the cytokines IL-6 and IL-1ß. Taken together, we demonstrate that gel phase liposomes, while nonimmunogenic on their own, significantly enhance the antigen-presenting ability of dendritic cells and appear to be a promising way forward to improve vaccine immunogenicity.

Alginate-chitosan coated layered double hydroxide nanocomposites for enhanced oral vaccine delivery.

Layered double hydroxide nanoparticles (LDHs) have shown the excellent capability and good adjuvant function as a nanocarrier for protein antigen delivery to enhance the immune response. Furthermore, LDHs have good biocompatibility and low cytotoxicity. However, their oral vaccine delivery efficiency is limited due to acidic/enzyme degradation in the stomach and low bioavailability in the small intestine. To overcome these challenges, alginate-chitosan coated LDHs nanocomposites (ALG-CHT-LDH) have been developed and used as a carrier for oral protein vaccine delivery. The physicochemical properties of ALG-CHT-LDH have been determined by dynamic light scattering (DLS), transmission electron microscopy (TEM), and ultraviolet visible (UV-Vis) spectroscopy. Protein release properties of LDHs with/without polymer coating have been investigated at various pHs. The protein release profile of ALG-CHT-LDH nanocomposites indicated that ALG-CHT coating could partially protect protein release at the acidic condition (pH 1.2). The cellular uptake efficiency of protein delivered by ALG-CHT-LDH for the intestine cells and macrophages were studied. After alginate layer falls from ALG-CHT-LDH nanocomposite, flow cytometry analysis (FACS) data suggest that chitosan-coated LDHs significantly enhance the internalization of proteins at the Caco2 and macrophage cells.

Vaccine Images on Twitter: Analysis of What Images are Shared.

BACKGROUND: Visual imagery plays a key role in health communication; however, there is little understanding of what aspects of vaccine-related images make them effective communication aids. Twitter, a popular venue for discussions related to vaccination, provides numerous images that are shared with tweets. OBJECTIVE: The objectives of this study were to understand how images are used in vaccine-related tweets and provide guidance with respect to the characteristics of vaccine-related images that correlate with the higher likelihood of being retweeted. METHODS: We collected more than one million vaccine image messages from Twitter and characterized various properties of these images using automated image analytics. We fit a logistic regression model to predict whether or not a vaccine image tweet was retweeted, thus identifying characteristics that correlate with a higher likelihood of being shared. For comparison, we built similar models for the sharing of vaccine news on Facebook and for general image tweets. RESULTS: Most vaccine-related images are duplicates (125,916/237,478; 53.02%) or taken from other sources, not necessarily created by the author of the tweet. Almost half of the images contain embedded text, and many include images of people and syringes. The visual content is highly correlated with a tweet's textual topics. Vaccine image tweets are twice as likely to be shared as nonimage tweets. The sentiment of an image and the objects shown in the image were the predictive factors in determining whether an image was retweeted. CONCLUSIONS: We are the first to study vaccine images on Twitter. Our findings suggest future directions for the study and use of vaccine imagery and may inform communication strategies around vaccination. Furthermore, our study demonstrates an effective study methodology for image analysis.

Efficacy of oral immunotherapy with a rice-based edible vaccine containing hypoallergenic Japanese cedar pollen allergens for treatment of established allergic conjunctivitis in mice.

BACKGROUND: We have previously shown that prophylactic oral administration of transgenic rice seeds expressing hypoallergenic modified antigens suppressed the development of allergic conjunctivitis induced by Japanese cedar pollen. We have now investigated the efficacy of oral immunotherapy with such transgenic rice for established allergic conjunctivitis in mice. METHODS: BALB/c mice were sensitized with two intraperitoneal injections of Japanese cedar pollen in alum, challenged with pollen in eyedrops, and then fed for 16 days with transgenic rice seeds expressing modified Japanese cedar pollen allergens Cry j 1 and Cry j 2 or with nontransgenic rice seeds as a control. They were then challenged twice with pollen in eyedrops, with clinical signs being evaluated at 15 min after the first challenge and the eyes, blood, spleen, and lymph nodes being isolated at 24 h after the second challenge. RESULTS: The number of eosinophils in the conjunctiva and the clinical score for conjunctivitis were both significantly lower in mice fed the transgenic rice than in those fed nontransgenic rice. Oral vaccination with transgenic rice seeds also resulted in a significant increase in the production of IFN-γ by splenocytes, whereas it had no effect on the number of CD4+CD25+Foxp3+ regulatory T cells in the spleen or submandibular or mesenteric lymph nodes. CONCLUSIONS: Oral administration of transgenic rice seeds expressing hypoallergenic allergens ameliorated allergic conjunctivitis in the established setting. Such a rice-based edible vaccine is potentially both safe and effective for oral immunotherapy in individuals with allergic conjunctivitis.

Screening Vaccine Formulations in Fresh Human Whole Blood.

Monitoring the immunological functionality of vaccine formulations is critical for vaccine development. While the traditional approach using established animal models has been relatively effective, the use of animals is costly and cumbersome, and animal models are not always reflective of a human response. The development of a human-based approach would be a major step forward in understanding how vaccine formulations might behave in humans. Here, we describe a platform methodology using fresh human whole blood (hWB) to monitor adjuvant-modulated, antigen-specific responses to vaccine formulations, which is amenable to analysis by standard immunoassays as well as a variety of other analytical techniques.

Analysis of human innate immune responses to PRINT fabricated nanoparticles with cross validation using a humanized mouse model.

Ideal nanoparticle (NP)-based drug and vaccine delivery vectors should be free of inherent cytotoxic or immunostimulatory properties. Therefore, determining baseline immune responses to nanomaterials is of utmost importance when designing human therapeutics. We characterized the response of human immune cells to hydrogel NPs fabricated using Particle Replication in Non-wetting Templates (PRINT) technology. We found preferential NP uptake by primary CD14(+) monocytes, which was significantly reduced upon PEGylation of the NP surface. Multiplex cytokine analysis of NP treated primary human peripheral blood mononuclear cells suggests that PRINT based hydrogel NPs do not evoke significant inflammatory responses nor induce cytotoxicity or complement activation. We furthered these studies using an in vivo humanized mouse model and similarly found preferential NP uptake by human CD14(+) monocytes without systemic inflammatory cytokine responses. These studies suggest that PRINT hydrogel particles form a desirable platform for vaccine and drug delivery as they neither induce inflammation nor toxicity. From the clinical editor: The authors here fabricated hydrogel nanorods using the PRINT (Particle Replication In Nonwetting Templates) fabrication process. They tested the interaction of human immune cells with these particles and found no immunoreactivity. This finding would suggest that monodisperse PRINT particles of identical shape and size could serve a variety of clinical applications.

Translational research in infectious disease: current paradigms and challenges ahead.

In recent years, the biomedical community has witnessed a rapid scientific and technologic evolution after the development and refinement of high-throughput methodologies. Concurrently and consequentially, the scientific perspective has changed from the reductionist approach of meticulously analyzing the fine details of a single component of biology to the "holistic" approach of broadmindedly examining the globally interacting elements of biological systems. The emergence of this new way of thinking has brought about a scientific revolution in which genomics, proteomics, metabolomics, and other "omics" have become the predominant tools by which large amounts of data are amassed, analyzed, and applied to complex questions of biology that were previously unsolvable. This enormous transformation of basic science research and the ensuing plethora of promising data, especially in the realm of human health and disease, have unfortunately not been followed by a parallel increase in the clinical application of this information. On the contrary, the number of new potential drugs in development has been decreasing steadily, suggesting the existence of roadblocks that prevent the translation of promising research into medically relevant therapeutic or diagnostic application. In this article, we will review, in a noninclusive fashion, several recent scientific advancements in the field of translational research, with a specific focus on how they relate to infectious disease. We will also present a current picture of the limitations and challenges that exist for translational research, as well as ways that have been proposed by the National Institutes of Health to improve the state of this field.

Fructans from aged garlic extract produce a delayed immunoadjuvant response to ovalbumin antigen in BALB/c mice.

Garlic (Allium sativum) is known for its innumerable biological activities including immunomodulation. Aged garlic extract (AGE), an odorless garlic preparation, has been shown to have superior immunomodulatory properties over raw garlic extract. Although garlic is a very rich source of fructans (17%, fresh weight basis), AGE contains only 0.22% of raw garlic fructans. Aged garlic fructans (AGF) have recently been shown to possess immunomodulatory activities in vitro. Natural adjuvants capable of eliciting better immune response of a model antigen are important in developing newer vaccines. In the present study, the adjuvant activity of AGF has been investigated in BALB/c mice using ovalbumin (OVA, 30 µg) as an experimental antigen. The body weights of animals did not change significantly indicating that the administration of garlic fructans is well-tolerated. AGF produce a significant humoral (serum IgG) response to OVA in BALB/c mice administered mucosally by either intranasal or oral route--a delayed response appearing on 50th day at a dose of 30 µg AGF by intranasal route. However, the serum IgG response was seen earlier on 35th day at a dose of 100 µg AGF by oral route. Higher concentrations of AGF (>50 µg) were inhibitory for adjuvant activity by intranasal administration. These observations indicate that AGF display immunoadjuvant activity for a test antigen though the humoral immune response is delayed.

Food and Drug Administration regulation and evaluation of vaccines.

The vaccine-approval process in the United States is regulated by the Center for Biologics Evaluation and Research of the US Food and Drug Administration. Throughout the life cycle of development, from preclinical studies to after licensure, vaccines are subject to rigorous testing and oversight. Manufacturers must adhere to good manufacturing practices and control procedures to ensure the quality of vaccines. As mandated by Title 21 of the Code of Regulations, licensed vaccines must meet stringent criteria for safety, efficacy, and potency.

Statistical, epidemiological, and risk-assessment approaches to evaluating safety of vaccines throughout the life cycle at the Food and Drug Administration.

The public health community faces increasing demands for improving vaccine safety while simultaneously increasing the number of vaccines available to prevent infectious diseases. The passage of the US Food and Drug Administration (FDA) Amendment Act of 2007 formalized the concept of life-cycle management of the risks and benefits of vaccines, from early clinical development through many years of use in large numbers of people. Harnessing scientific and technologic advances is necessary to improve vaccine-safety evaluation. The Office of Biostatistics and Epidemiology in the Center for Biologics Evaluation and Research is working to improve the FDA's ability to monitor vaccine safety by improving statistical, epidemiologic, and risk-assessment methods, gaining access to new sources of data, and exploring the use of genomics data. In this article we describe the current approaches, new resources, and future directions that the FDA is taking to improve the evaluation of vaccine safety.

Commonly used prophylactic vaccines as an alternative for synthetically produced TLR ligands to mature monocyte-derived dendritic cells.

Currently dendritic cell (DC)-based vaccines are explored in clinical trials, predominantly in cancer patients. Murine studies showed that only maturation with Toll-like receptor (TLR) ligands generates mature DCs that produce interleukin-12 and promote optimal T-cell help. Unfortunately, the limited availability of clinical-grade TLR ligands significantly hampers the translation of these findings into DC-based vaccines. Therefore, we explored 15 commonly used preventive vaccines as a possible source of TLR ligands. We have identified a cocktail of the vaccines BCG-SSI, Influvac, and Typhim that contains TLR ligands and is capable of optimally maturing DCs. These DCs (vaccine DCs) showed high expression of CD80, CD86, and CD83 and secreted interleukin-12. Although vaccine DCs exhibited an impaired migratory capacity, this could be restored by addition of prostaglandin E(2) (PGE(2); vaccine PGE(2) DCs). Vaccine PGE(2) DCs are potent inducers of T-cell proliferation and induce Th1 polarization. In addition, vaccine PGE(2) DCs are potent inducers of tumor antigen-specific CD8(+) effector T cells. Finally, vaccine PGE(2)-induced DC maturation is compatible with different antigen-loading strategies, including RNA electroporation. These data thus identify a new clinical application for a mixture of commonly used preventive vaccines in the generation of Th1-inducing clinical-grade mature DCs.

In vivo immunomodulatory effects of dietary purple sweet potato after immunization in chicken.

This study was intended to determine the modulatory effects of dietary supplementation of purple sweet potato (Ipomoea batats Poir., PSP) on the immune response of chickens. PSP was included in a basal starter diet by 1% (PSP(L)) or 3% (PSP(H)) and continually fed. Newcastle disease (NDV) vaccine, Brucella abortus (BA) and sheep red blood cells (SRBC) were used for chicken immunization. Antibody titers against these antigens were used to estimate humoral immunity. Concanavalin A (Con A)-induced proliferations of splenocytes, thymocytes and peripheral blood lymphocytes (PBL), ratios of CD4- and CD8-single positive and CD4-CD8-double negative (DN) cells in splenocytes, were both used to indicate cellular immunity. Relative weights of spleen, thymus and bursa and white blood cell (WBC) counts were studied. PSP(H) increased anti-NDV (P < 0.05), anti-BA (P < 0.01) and anti-SRBC titers (P < 0.05) in response to secondary immunization, whereas PSP(L) increased titers of anti-BA (P < 0.05) and anti-SRBC (P < 0.01). Proliferations of splenocytes and thymocytes were augmented with PSP(L) (P < 0.05). PSP(H)-treated chickens had lower (P < 0.05) ratios of CD4-single positive lymphocytes. Proliferation of PBL, weights of lymphoid organs and WBC counts were not affected. These results suggest that dietary PSP supplementation could enhance the immune response after immunization in chickens.

Oral administration of PPC enhances antigen-specific CD8+ T cell responses while reducing IgE levels in sensitized mice.

BACKGROUND: For almost 2000 years it has been recognized that aqueous extracts from pine cones possess medicinal properties beneficial for the treatment of a broad variety of diseases and conditions. In this report, the ability of an orally administered poly phenylpropanoid-polysaccharide rich extract of pine cones (PPC) to suppress the generation of IgE and to significantly enhance antigen-specific cellular responses to a variety of vaccines was tested. METHODS: A variety of vaccine protocols were utilized to determine the affects of orally administered PPC on the Th1/Th2 cytokine balance, the production of IgE antibodies, and the generation of antigen-specific cytotoxic T cells. The effect of PPC on the Th1/Th2 balance in aged mice was also investigated. RESULTS: Oral delivery of PPC was found to significantly suppress serum IgE levels in naïve mice and in mice sensitized to ovalbumin. PPC was also found to enhance the generation of antigen-specific CD8+ T cells in mice immunized with DNA, dendritic cell, and soluble protein vaccines. The suppression of IgE was associated with reduction of IL-4 secretion and the enhanced production of IL-12 and IFNgamma by antigen-stimulated splenocytes from PPC treated mice. PPC also suppressed the Th2 response and enhanced the Th1 response of splenocytes from aged mice. CONCLUSION: Oral delivery of PPC enhances the generation of an antigen-specific CD8+ T cell responses induced by soluble protein, DNA, and dendritic cell vaccines while at the same time suppressing the generation of a Th2 dominant IgE response. This effect on the Th1/Th2 balance was also observed in aged mice.