Formulation approach for the development of a stable, lyophilized formaldehyde-containing vaccine

Formaldehyde has been used in the inactivation of a number of viral and bacterial toxins used in vaccines. In some cases, a small amount of formaldehyde may be necessary in order to prevent reversion back to the toxic state during storage. When a lyophilized preparation is required, care must be taken to ensure that formaldehyde is not lost during the process in order to ensure safety of the product. A design of experiments (DOEs) approach was taken to devise a stable, lyophilized, vaccine formulation. A formaldehyde-inactivated bacterial toxin was used as a model antigen. Entrapment of formaldehyde in an amorphous matrix and/or interactions with amorphous components was found to be required for complete recovery of formaldehyde during lyophilization. In formulations consisting of sucrose and citrate, formaldehyde could be recovered across a wide range of excipient concentrations. Stability of the antigen was dependent on formaldehyde concentration, with antigen stability decreasing with increasing formaldehyde concentration. This is in contrast to the risk of reversion which increases with decreasing concentrations of formaldehyde. Finally, variations in temperatures during annealing, primary drying, and secondary drying had no impact on formaldehyde recovery.

Duration of equine influenza virus shedding and infectivity in immunised horses after experimental infection with EIV A/eq2/Richmond/1/07

Equine influenza (EI) is a major respiratory disease of horses. Recent outbreaks of EI have demonstrated the ease with which EI virus (EIV) can be transmitted internationally. This study aimed to improve our understanding of EIV shedding after infection of vaccinated horses, which would inform possible changes to current quarantine requirements. Our objectives were to compare commonly used diagnostic tests and to evaluate the relative merits of nasal and nasopharyngeal swabs for detection of EIV in vaccinated and unvaccinated ponies following EIV infection and to use these data to inform optimal quarantine procedures for the safe international movement of horses. Five ponies vaccinated against EI were infected experimentally with A/eq/Richmond/1/07 (Florida clade 2), 11 weeks after V2. Nasal and nasopharyngeal swabs were taken daily for 14 days and every 2 days for another 2 weeks. The 5 vaccinates were introduced sequentially for 48h to 3 groups of 2 naïve sentinel ponies each on days 2, 4 and 6 post-challenge respectively. Clinical signs of disease and EIV shedding were monitored for 14 days after co-mingling. EIV was detected by 3 different methods of detection (EIV nucleoprotein ELISA, EIV nucleoprotein qRT-PCR and isolation/titration in embryonated hens' eggs). Directigen™ EZ Flu A+B tests were also performed on samples from the vaccinated ponies for 6 days after infection. Results show that nasopharyngeal swabs were superior to nasal swabs, with increased frequency and amount of virus detected. The average mean duration of shedding was 6-8 days in naïve animals. All 3 sentinel groups were infected successfully with EIV after commingling with vaccinates, indicating up to 6 days of transmission. EI protection induced by vaccination is a dynamic process, naturally fluctuating and dependent on the time since last immunisation, with periods of high immunity (peak of immunity shortly after boost immunisation) and periods of susceptibility to EIV infection. This result indicates that vaccinated horses may actively transmit EIV if the immunity gap (a usual period of susceptibility between V2 and V3) is not adequately closed by immunisation. In infected sentinels EIV was detectable up to 12 days after commingling. Results also suggest that tests such as qRT-PCR may be a suitable substitute for time spent in pre-export quarantine.

Low immunogenicity predicted for emerging avian-origin H7N9: implication for influenza vaccine design

A new avian-origin influenza virus emerged near Shanghai in February 2013, and by the beginning of May it had caused over 130 human infections and 36 deaths. Human-to-human transmission of avian-origin H7N9 influenza A has been limited to a few family clusters, but the high mortality rate (27%) associated with human infection has raised concern about the potential for this virus to become a significant human pathogen. European, American, and Asian vaccine companies have already initiated the process of cloning H7 antigens such as hemagglutinin (HA) into standardized vaccine production vehicles. Unfortunately, previous H7 HA-containing vaccines have been poorly immunogenic. We used well-established immunoinformatics tools to analyze the H7N9 protein sequences and compare their T cell epitope content to other circulating influenza A strains as a means of estimating the immunogenic potential of the new influenza antigen. We found that the HA proteins derived from closely related human-derived H7N9 strains contain fewer T cell epitopes than other recently circulating strains of influenza, and that conservation of T cell epitopes with other strains of influenza was very limited. Here, we provide a detailed accounting of the type and location of T cell epitopes contained in H7N9 and their conservation in other H7 and circulating (A/California/07/2009, A/Victoria/361/2011, and A/Texas/50/2012) influenza A strains. Based on this analysis, avian-origin H7N9 2013 appears to be a “stealth” virus, capable of evading human cellular and humoral immune response. Should H7N9 develop pandemic potential, this analysis predicts that novel strategies for improving vaccine immunogenicity for this unique low-immunogenicity strain of avian-origin influenza will be urgently needed.

Novel particulate vaccines utilizing polyester nanoparticles (bio-beads) for protection against Mycobacterium bovis infection - a review

Bovine tuberculosis (TB) continues to be a major health problem in cattle and development of a safe effective vaccine to control TB in cattle would be very useful. This paper reviews progress and provides new data in development of a TB bio-bead vaccine based on polyester nanoparticle inclusions which were produced by bioengineered bacteria. Polyhydroxybutyrate (PHB) biopolyester nanoparticles (bio-beads) have been produced which displayed mycobacterial antigens, Ag85A and ESAT-6, on the surface of the bio-beads for use as vaccines for the control of tuberculosis. Bio-beads were purified from the host production bacteria, Escherichia coli and the generally regarded as safe (GRAS) bacterium, Lactococcus lactis. Previous published studies showed that vaccination with Ag85A/ESAT-6 bio-beads induced antigen-specific IFN-γ, IL-17A, IL-6, TNF-α and IL-2 in splenocytes, but no significant increase in IL-4, IL-5 or IL-10. New results showed that antigen-specific IFN-γ release was induced by both CD4 and CD8 T cells in mice vaccinated with the Ag85A/ESAT-6 bio-beads. Mice vaccinated with Ag85A/ESAT-6 bio-beads alone or in combination with BCG had significantly lower bacterial counts from the lungs and spleen following aerosol challenge with Mycobacterium bovis compared to control groups. This unique approach to the design and production of bacterial-derived bio-beads displaying antigens enables a cost-effective way to express a diverse antigen repertoire for use as vaccines to combat TB or other diseases.

Is vaccination with quadrivalent HPV vaccine after loop electrosurgical excision procedure effective in preventing recurrence in patients with high-grade cervical intraepithelial neoplasia (CIN2-3)?

OBJECTIVES

This study was conducted to determine whether vaccination with the quadrivalent human papillomavirus (HPV) vaccine after loop electrosurgical excision procedure (LEEP) for high-grade cervical intraepithelial neoplasia (CIN2-3) is effective in preventing recurrence of CIN2-3.

METHODS

Between August 2007 and July 2010, 737 patients aged 20-45 years who were diagnosed with CIN2-3 were treated by LEEP and followed. Three hundred and sixty patients were vaccinated with the quadrivalent HPV vaccine after LEEP (vaccination group), and 377 patients were followed without vaccination (non-vaccination group). The vaccination group received the first dose at 1 week after LEEP and the remaining two doses two and six months later. Post-LEEP follow-up was performed at 3, 6, 9, 12, 18, and 24 months during the first 2 years and yearly thereafter.

RESULTS

Irrespective of causal HPV type, 36 (4.9%) patients developed recurrence. In the vaccination group (360 patients), 9 patients (2.5%) developed recurrence, whereas 27 patients (7.2%) in the non-vaccination group (377 patients) developed recurrence. In patients infected with HPV of 16 and/or 18 type, 5 patients (2.5%) in the vaccination group (197 patients) and 18 patients (8.5%) in the non-vaccination group (211 patients) developed recurrent disease related to vaccine HPV types (HPV 16 or 18 types) after LEEP (P<0.01). Multivariate analysis showed that no vaccination after LEEP was an independent risk factor for recurrent CIN2-3 (HR=2.840; 95% confidence interval, 1.335-6.042; P<0.01).

CONCLUSIONS

Vaccination with the quadrivalent HPV vaccine after treatment may be considered in preventing recurrence of CIN2-3.

Clinical trials for vaccine development in registry of Korea Food and Drug Administration

Based on the action plan "Ensuring a stable supply of National Immunization Program vaccines and sovereignty of biopharmaceutical products," Korea Food and Drug Administration (KFDA) has made efforts to develop vaccines in the context of self reliance and to protect public health. Along with the recognized infrastructures for clinical trials, clinical trials for vaccines have also gradually been conducted at multinational sites as well as at local sites. KFDA will support to expand six to eleven kinds of vaccines by 2017. In accordance with integrated regulatory system, KFDA has promoted clinical trials, established national lot release procedure, and strengthened good manufacturing practices inspection and post marketing surveillance. Against this backdrop, KFDA will support the vaccine development and promote excellent public health protection.

Adaptation of yellow fever virus 17D to Vero cells is associated with mutations in structural and non-structural protein genes

Serial passaging of yellow fever virus 17D in Vero cells was employed to derive seed material for a novel inactivated vaccine, XRX-001. Two independent passaging series identified a novel lysine to arginine mutation at amino acid 160 of the envelope protein, a surface-exposed residue in structural domain I. A third passage series resulted in an isoleucine to methionine mutation at residue 113 of the NS4B protein, a central membrane spanning region of the protein which has previously been associated with Vero cell adaptation of other mosquito-borne flaviviruses. These studies confirm that flavivirus adaptation to growth in Vero cells can be mediated by structural or non-structural protein mutations.

Strangles: taking steps towards eradication

Strangles, caused by the host adapted Lancefield group C bacterium Streptococcus equi sub-species equi (S. equi), is one of the oldest recognised infectious diseases of horses and continues to cause significant welfare and economic cost throughout the world. The ability of S. equi to establish sub-clinical persistent infections primarily in the guttural pouches of convalescent horses has been instrumental to its success. However, the implementation of simple control measures that permit the identification and treatment of persistently infected carriers can prevent further outbreaks of disease at a local level. This review summarises some of the molecular mechanisms exploited by S. equi to cause disease. New qPCR and iELISA diagnostic tests replace culture methodologies as the gold standard for the detection of infected animals. A strategy to maximise the effective application of these tests to direct management methods for the eradication of S. equi infection is presented and the role of preventative vaccines is discussed. In contrast to current understanding, emerging data illustrates the dynamism of the global S. equi population and potential consequences for the effectiveness of currently available vaccines. The ability to use modern vaccines alongside conventional biosecurity and screening procedures will be critical to the large-scale prevention and even eradication of strangles, providing an opportunity to finally break the stranglehold that this disease has on the world's equine industry.

Computational Resources for MHC Ligand Identification

Advances in the high-throughput determination of functional modulators of major histocompatibility complex (MHC) and improved computational predictions of MHC ligands have rendered the rational design of immunomodulatory peptides feasible. Proteome-derived peptides and 'reverse vaccinology' by computational means will play a driving role in future vaccine design. Here we review the molecular mechanisms of the MHC mediated immune response, present the computational approaches that have emerged in this area of biotechnology, and provide an overview of publicly available computational resources for predicting and designing new peptidic MHC ligands.

Immunization with tegument nucleotidases associated with a subcurative praziquantel treatment reduces worm burden following Schistosoma mansoni challenge

Schistosomiasis is a debilitating disease caused by flatworm parasites of the Schistosoma genus and remains a high public health impact disease around the world, although effective treatment with Praziquantel (PZQ) has been available since the 1970s. Control of this disease would be greatly improved by the development of a vaccine, which could be combined with chemotherapy. The sequencing of the Schistosoma mansoni transcriptome and genome identified a range of potential vaccine antigens. Among these, three nucleotidases from the tegument of the parasite, presumably involved in purinergic signaling and nucleotide metabolism, were proposed as promising vaccine candidates: an alkaline phosphatase (SmAP), a phosphodiesterase (SmNPP-5) and a diphosphohydrolase (SmNTPDase). Herein, we evaluate the potential of these enzymes as vaccine antigens, with or without subcurative PZQ treatment. Immunization of mice with the recombinant proteins alone or in combination demonstrated that SmAP is the most immunogenic of the three. It induced the highest antibody levels, particularly IgG1, associated with an inflammatory cellular immune response characterized by high TNF-α and a Th17 response, with high IL-17 expression levels. Despite the specific immune response induced, immunization with the isolated or combined proteins did not reduce the worm burden of challenged mice. Nonetheless, immunization with SmAP alone or with the three proteins combined, together with subcurative PZQ chemotherapy was able to reduce the worm burden by around 40%. The immunogenicity and relative exposure of SmAP to the host immune system are discussed, as key factors involved in the apparently synergistic effect of SmAP immunization and subcurative PZQ treatment.

Clostridium difficile PSI polysaccharide: synthesis of pentasaccharide repeating block, conjugation to exotoxin B subunit, and detection of natural anti-PSI IgG antibodies in horse serum

Clostridium difficile is the most common cause of antimicrobial-associated diarrhea in humans and may cause death. Previously, we discovered that C. difficile expresses three polysaccharides, named PSI, PSII, and PSIII. It has now been established that PSII is a conserved antigen abundantly present on the cell-surface and biofilm of C. difficile. In contrast, the expression of PSI and PSIII appears to be stochastic processes. In this work, the total chemical synthesis of the PSI pentasaccharide repeating unit carrying a linker at the reducing end, α-l-Rhap-(1→3)-β-d-Glcp-(1→4)-[α-l-Rhap-(1→3)]-α-d-Glcp-(1→2)-α-d-Glcp-(1→O(CH2)5NH2, was achieved by a linear synthesis strategy from four monosaccharide building blocks. The synthesized PSI pentasaccharide was conjugated to a subunit of C. difficile exotoxin B yielding a potential dual C. difficile vaccine. More significantly, sera from healthy horses were shown to contain natural anti-PSI IgG antibodies that detected both the synthetic non-phosphorylated PSI repeat and the native PSI polysaccharide, with a slightly higher recognition of the native PSI polysaccharide.

Clinical development of Modified Vaccinia virus Ankara vaccines. Vaccine. 2013;31:4241-4246. [PMID: 23523410 DOI: 10.1016/j.vaccine.2013.03.020]

The smallpox vaccine Vaccinia was successfully used to eradicate smallpox, but although very effective, it was a very reactogenic vaccine and responsible for the deaths of one or two people per million vaccinated. Modified Vaccinia virus Ankara (MVA) is a replication-deficient and attenuated derivative, also used in the smallpox eradication campaign and now being developed as a recombinant viral vector to produce vaccines against infectious diseases and cancer. Many clinical trials of these new vaccines have been conducted, and the findings of these trials are reviewed here. The safety of MVA is now well documented, immunogenicity is influenced by the dose and vaccination regimen, and information on the efficacy of MVA-vectored vaccines is now beginning to accumulate.

Recombinant MVA vaccines: dispelling the myths

Diseases such as HIV/AIDS, tuberculosis, malaria and cancer are prime targets for prophylactic or therapeutic vaccination, but have proven partially or wholly resistant to traditional approaches to vaccine design. New vaccines based on recombinant viral vectors expressing a foreign antigen are under intense development for these and other indications. One of the most advanced and most promising vectors is the attenuated, non-replicating poxvirus MVA (modified vaccinia virus Ankara), a safer derivative of the uniquely successful smallpox vaccine. Despite the ability of recombinant MVA to induce potent humoral and cellular immune responses against transgenic antigen in humans, especially when used as the latter element of a heterologous prime-boost regimen, doubts are occasionally expressed about the ultimate feasibility of this approach. In this review, five common misconceptions over recombinant MVA are discussed, and evidence is cited to show that recombinant MVA is at least sufficiently genetically stable, manufacturable, safe, and immunogenic (even in the face of prior anti-vector immunity) to warrant reasonable hope over the feasibility of large-scale deployment, should useful levels of protection against target pathogens, or therapeutic benefit for cancer, be demonstrated in efficacy trials.

Template protocol for clinical trials investigating vaccines--focus on safety elements

This document is intended as a guide to the protocol development for trials of prophylactic vaccines. The template may serve phases I-IV clinical trials protocol development to include safety relevant information as required by the regulatory authorities and as deemed useful by the investigators. This document may also be helpful for future site strengthening efforts.

Noroviruses: The Most Common Pediatric Viral Enteric Pathogen at a Large University Hospital After Introduction of Rotavirus Vaccination

We conducted an 8.5-year study examining enteric viruses at Texas Children's Hospital (TCH) before and after rotavirus vaccine introduction. Norovirus prevalence was 10.9%. Rotavirus prevalence decreased 64% after vaccine licensure. Noroviruses are the most common TCH enteropathogen and will likely eclipse rotaviruses as the most important US pediatric gastroenteritis pathogen.

Current biodefense vaccine programs and challenges

The Defense Threat Reduction Agency's Joint Science and Technology Office manages the Chemical and Biological Defense Program's Science and Technology portfolio. The Joint Science and Technology Office's mission is to invest in transformational ideas, innovative people and actionable technology development for Chemical and Biological Defense solutions, with the primary goal to deliver Science and Technology products and capabilities to the warfighter and civilian population that outpace the threat. This commentary focuses on one thrust area within this mission: the Vaccine program of the Joint Science and Technology Office's Translational Medical Division. Here, we will describe candidate vaccines currently in the S&T pipeline, enabling technologies that should facilitate advanced development of these candidates into FDA licensed vaccines, and how the ever-changing biological threat landscape impacts the future of biodefense vaccines.

[News items on human papillomavirus and its vaccine in the Valencian press (2006-2011)]

The process of introducing the human papillomavirus (HPV) vaccine aimed at teenage girls has not been entirely without controversy in Spain. This vaccine was originally hyped as a preventive measure in the fight against cervical cancer but the resulting euphoria was tempered by a message calling for evidence. During administration of the second dose of the vaccine in February 2009, an unexpected turn of events attracted vast media coverage when two teenagers experienced adverse effects after immunization in Valencia (Spain). This study analyzes the scope and content of news items on HPV, immunization and cervical cancer published between 2006 and 2011 in two widely disseminated regional newspapers in Valencia. We also discuss the extent to which the messages transmitted may have influenced acceptability of the vaccine.

Awareness, knowledge and beliefs about HPV, cervical cancer and HPV vaccines among nurses in Cameroon: an exploratory study

BACKGROUND

While it is known that sub-Saharan African countries face multiple obstacles such as cost in adopting vaccination against human papillomavirus (HPV), the crucial role nurses can play in implementing such programs has not been adequately examined.

OBJECTIVES

To investigate the knowledge and awareness of HPV, primary cause of cervical cancer and HPV vaccine among nurses working at four Cameroon Baptist Convention Health Services facilities, and to explore what factors influence nurses' willingness to inform and recommend HPV vaccine to adolescents and parents attending clinics.

DESIGN AND SETTING

A structured questionnaire survey was administered to a convenience sample of nursing staff working at the four health facilities.

RESULTS

Of 192 eligible nurses 76 (39.6%) participated in the study. There were moderately low levels of knowledge about HPV infection and prevention of cervical cancer, but a moderately high level of knowledge about HPV vaccine. Although 90.8% acknowledged that cervical cancer is directly linked to HPV infection, nearly 32% failed to identify it as a sexually transmitted infection (STI), while 43.4% believed it is an uncommon infection. Willingness to recommend the HPV vaccine was moderate, with 69.7% intentionally initiating discussions with patients about the subject. The most important factors considered when deciding to recommend the vaccine included effectiveness (56.6%) and side effects/safety (11.8%). Cost was less of a concern (6.6%), likely due to the availability of donated vaccine.

CONCLUSION

Despite high awareness about HPV, more education about the virus, cervical cancer and the vaccine are required to further increase nurses' willingness to recommend the vaccine and strengthen strategies for reaching adolescents through nurses in Cameroon.

Preclinical evaluation of a two-dose vaccination schedule of recombinant Hansenula polymorpha hepatitis B vaccine in animals

AIMS

The current 3-dose regimen of hepatitis B vaccination for infants requiring over 6 mo period may pose the poor rate of compliance and later protection from hepatitis B virus (HBV) infection. This preclinical study is to investigate the feasibility of reducing the number of doses of hepatitis B (HB) vaccine.

RESULTS

Eight groups of guinea pigs immunized with two doses of HP-HB vaccines at either 0 and 4 weeks or 0 and 8 weeks elicited geometric titers (GMT) of anti-HBs similar to that of four groups immunized with three doses of controls. The overall GMT of anti-HBs were not significantly different between the E- and C-groups (p>0.05) of monkeys. Specifically, the anti-HBs titers in the C-group reached the peak of 24857 (938.3-104585) mIU/mL one week after the 3rd dose, which were statistically higher than those of the E-group. However, they were reduced to comparable levels of anti-HBs in the E-group during weeks 9-12, suggesting comparable immune response of both vaccination regimens.

METHODS

Twelve groups of guinea pigs (four animals in each group) were immunized with 2 experimental recombinant yeast Hansenula Polymorpha derived HB vaccines (HP-HB vaccine) and 2 commercial recombinant yeast Saccharomyces Cerevisiae vaccines (Temrevac-HB) as controls at 0, 4 and 8 weeks, 0 and 4 weeks, and 0 and 8 weeks respectively. Each guinea pig received 2 µg vaccine. Twelve Cynomolgus monkeys were randomly divided into two groups (six animals in each group). Animals in the experimental group (E-group) were injected with two doses of pilot produced 20 µg HP-HB vaccine. Animals in the control group (C-Group) were immunized with three doses of 10 µg Temrevac-HB. Both vaccines were administered at an interval of 3 weeks for monkeys.

CONCLUSIONS

The 2-dose regimen of the HP-HB vaccine has comparable HBV immune responses as the 3-dose regimen of Temrevac-HB vaccine in Cynomolgus monkeys.

Requirements for improved vaccines against foot-and-mouth disease epidemics

Inactivated foot-and-mouth disease (FMD) vaccines are currently used worldwide. With the emergence of various FMD virus serotypes and subtypes, vaccines must become more suitable for field-based uses under the current circumstances in terms of the fast and proper selection of vaccine strains, an extended vaccine development period for new viruses, protecting against the risk of virus leakage during vaccine manufacture, counteracting the delayed onset of immune response, counteracting shorter durations of immunity, and the accurate serological differentiation of infected and vaccinated animals and multiple vaccination. The quality of vaccines should then be improved to effectively control FMD outbreaks and minimize the problems that can arise among livestock after vaccinations. Vaccine improvement should be based on using attenuated virus strains with high levels of safety. Moreover, when vaccines are urgently required for newly spread field strains, the seed viruses for new vaccines should be developed for only a short period. Improved vaccines should offer superior immunization to all susceptible animals including cattle and swine. In addition, they should have highly protective effects without persistent infection. In this way, if vaccines are developed using new methods such as reverse genetics or vector vaccine technology, in which live viruses can be easily made by replacing specific protective antigens, even a single vaccination is likely to generate highly protective effects with an extended duration of immunity, and the safety and stability of the vaccines will be assured. We therefore reviewed the current FMD vaccines and their adjuvants, and evaluated if they provide superior immunization to all susceptible animals including cattle and swine.

H9N2 avian influenza virus in Korea: evolution and vaccination

Low pathogenic avian influenza (LPAI) H9N2 viruses have been circulating in the Eurasian poultry industry resulting in great economic losses due to declined egg production and moderate to high mortality. In Korea, H9N2 LPAI was first documented in 1996 and it caused serious economic loss in the Korean poultry industry, including layer and broiler breeder farms. Since then, the H9N2 viruses that belong to the Korea group have been prevalent in chickens and have continuously evolved through reassortment in live bird markets. To control LPAI outbreaks, since 2007, the Korean veterinary authority has permitted the use of the inactivated oil adjuvant H9N2 LPAI vaccine. Although only oil-based inactivated vaccine using the egg-passaged vaccine virus strain (A/chicken/Korea/01310/2001) is permitted and used, several new technology vaccines have been recently suggested for the development of cost-effective and highly immunogenic vaccines. In addition, several different differentiation of infected from vaccinated animals (DIVA) strategies have been suggested using appropriate vaccines and companion serologic tests for discriminating between naturally infected and vaccinated animals. Recent reports demonstrated that the Korean LPAI H9N2 virus underwent antigenic drift and evolved into distinct antigenic groups and thus could escape from vaccine protection. Therefore, improved vaccination strategies including periodic updates of vaccine seed strains are required to achieve efficient control and eradication of LPAI H9N2 in Korea. Further, vaccination should be part of an overall integrated strategy to control the disease, including continued nation-wide surveillance, farm biosecurity, and DIVA strategy.

PLGA-polymer encapsulating tumor antigen and CpG DNA administered into the tumor microenvironment elicits a systemic antigen-specific IFN-γ response and enhances survival

Critical to the generation of an effective therapeutic antitumor immune response is the elicitation of effective antigen presentation coupled with overcoming tumor-immune escape mechanisms. Towards this end, we aimed to understand the therapeutic effectiveness of a polymer based vaccine approach at enhancing the anti-tumor responses in a tumor-bearing mouse model. While we and others have previously demonstrated the effectiveness of PLGA based systems in delivering antigen etc., studies scarcely focus on understanding the immunological mechanisms of polymer based therapies in tumor bearing treatment models. Considering tumors modulate the immune system and consequently the efficacy of therapies, understanding treatment mechanisms in the presence of tumor will help lead to more efficacious treatment options. We demonstrate here that a poly(lactic-co-glycolic acid) (PLGA) based delivery system encapsulating tumor antigen (OVA) and the TLR9 agonist CpG motif DNA administered into the tumor microenvironment initiates an effective type 1 mediated (IFN-γ producing) anti-tumor response in a syngeneic murine model of T cell lymphoma (E.G7-OVA). Although E.G7-OVA tumors spontaneously generate antigen specific CTLs in draining lymph nodes (LN), tumors progress rapidly. Modulation of the tumor microenvironment via local PLGA based therapy led to the generation of a systemic antigen specific Th1 response, absent in the non-polymer delivery method, subsequently associated with reduced tumor growth and prolongation of survival. These studies provide further insight into the use of a PLGA-based therapeutic approach at modulating the tumor microenvironment and highlight the need for analyzing the treatment effects in a tumor bearing model.

Low seroconversion after one dose of AS03-adjuvanted H1N1 pandemic influenza vaccine in solid-organ transplant recipients

BACKGROUND

Immunocompromised individuals are more susceptible to complications produced by influenza infection. As a result, solid-organ transplant (SOT) recipients were targeted as a priority group to receive AS03-adjuvanted H1N1 influenza vaccine during 2009.

OBJECTIVE

To evaluate seroconversion after one dose of adjuvanted pandemic influenza H1N1 (pH1N1) vaccine in SOT recipients.

METHODS

Adult SOT recipients were enrolled to receive one 3.75 μg dose of adjuvanted pH1N1 vaccine. Serological status was tested using a hemagglutination inhibition assay before and two and four weeks postvaccination.

RESULTS

The five SOT recipients (one liver, two kidney and two lung transplants) had a median age of 50 years (range 36 to 53 years), and three were male, who were a median time of three years (range two months to 15 years) post-transplant. All patients were on a double or triple immunosuppressive regimen. The prevaccination pH1N1 titre was 1:10 in four patients and 1:40 in one patient. Seroprotection was observed only in one patient, with a rise in titre from 1:40 at baseline to 1:320 at both two and four weeks after vaccination. This lung transplant recipient had documented previous infection with pH1N1.

CONCLUSION

Results of the present small study call into question whether one dose of adjuvanted pH1N1 vaccine can provide seroprotection in SOT recipients.

Identification of Tropomyosin and Its Immunological Properties from Larvae of Cattle Tick, Boophilus annulatus

BACKGROUND

Boophilus annulatus is an obligate blood feeder tick that can cause great losses in animals due to anemia and its ability to injure its host skin directly. The aim of this study was identification of cattle humoral immune response to some tick proteins during experimental infestation.

METHODS

Immune sera against tick were collected from experimentally infested cattle with ticks. One and two-dimensional electrophoresis and Western blotting methods were used for the detection of immunogenic proteins in larval tick extract and eight of these proteins were identified by MALDITOF and MALDI-TOF-TOF mass spectrometry.

RESULTS

In non-reducing one-dimensional SDS-PAGE, some bounds between 12 to more than 250-kDa appeared. In two-dimensional SDS-PAGE, numerous spot appeared and the identified immunogenic proteins by parallel immunoblotting weighted between 14 and 97 kDa. Amino acid sequences of protein spot with 37-kDa molecular weight had identity to tropomyosin based on Mascot search in NCBI.

CONCLUSION

Anti tropomyosin antibodies can be induced in experimentally infested hosts with ticks and it seems that tropomyosin can be useful for the development of anti tick vaccines.

Uptake of biodegradable poly(γ-glutamic acid) nanoparticles and antigen presentation by dendritic cells in vivo

Poly(γ-glutamic acid) (γ-PGA) nanoparticles (NPs) carrying antigens have been shown to induce potent antigen-specific immune responses. However, in vivo delivery of γ-PGA NPs to dendritic cells (DCs), a key regulator of immune responses, still remains unclear. In this study, γ-PGA NPs were examined for their uptake by DCs and subsequent migration from the skin to the regional lymph nodes (LNs) in mice. After subcutaneous injection of fluorescein 5-isothiocyanate (FITC)-labeled NPs or FITC-ovalbumin (OVA)-carrying NPs (FITC-OVA-NPs), DCs migrated from the skin to the LNs and maturated, resulting in the upregulation of the costimulatory molecules CD80 and CD86 and the chemokine receptor CCR7. However, the migrated DCs were not detected in the spleen. FITC-OVA-NPs were found to be taken up by skin-derived CD103(+) DCs, and the processed antigen peptides were cross-presented by the major histocompatibility complex (MHC) class I molecule of DCs. Furthermore, significant activation of antigen-specific CD8(+) T cells was observed in mice immunized with OVA-carrying NPs (OVA-NPs) but not with OVA alone or OVA with an aluminum adjuvant. The antigen-specific CD8(+) T cells were induced within 7 days after immunization with OVA-NPs. Thus, γ-PGA NPs carrying various antigens may have great potential as an antigen-delivery system and vaccine adjuvant in vivo.

HIV-1 Vaccine Trials: Evolving Concepts and Designs

An effective prophylactic HIV-1 vaccine is needed to eradicate the HIV/AIDS pandemic but designing such a vaccine is a challenge. Despite many advances in vaccine technology and approaches to generate both humoral and cellular immune responses, major phase-II and -III vaccine trials against HIV/AIDS have resulted in only moderate successes. The modest achievement of the phase-III RV144 prime-boost trial in Thailand re-emphasized the importance of generating robust humoral and cellular responses against HIV. While antibody-directed approaches are being pursued by some groups, others are attempting to develop vaccines targeting cell-mediated immunity, since evidence show CTLs to be important for the control of HIV replication. Phase-I and -IIa multi-epitope vaccine trials have already been conducted with vaccine immunogens consisting of known CTL epitopes conserved across HIV subtypes, but have so far fallen short of inducing robust and consistent anti-HIV CTL responses. The concepts leading to the development of T-cell epitope-based vaccines, the outcomes of related clinical vaccine trials and efforts to enhance the immunogenicity of cell-mediated approaches are summarized in this review. Moreover, we describe a novel approach based on the identification of SIV and FIV antigens which contain conserved HIV-specific T-cell epitopes and represent an alternative method for developing an effective HIV vaccine against global HIV isolates.

Preventing the broad spectrum of perinatal morbidity and mortality through group B streptococcal vaccination

The development of a group B streptococcal (GBS) glycoconjugate vaccine and its upcoming evaluation in a phase 3 trial in pregnant women highlight the importance of defining the anticipated impact of GBS vaccination upon the broad spectrum of GBS-related perinatal morbidity and mortality. We present the specific pregnancy-associated and neonatal conditions attributable, at least in part, to GBS in high and lower income countries. We offer a rationale to support our contention that implementation of GBS glycoconjugate immunization during pregnancy will reduce the global burden of GBS-related morbidity and mortality in pregnant women and their infants.

Mucosal Immune System and M Cell-targeting Strategies for Oral Mucosal Vaccination

Vaccination is one of the most effective methods available to prevent infectious diseases. Mucosa, which are exposed to heavy loads of commensal and pathogenic microorganisms, are one of the first areas where infections are established, and therefore have frontline status in immunity, making mucosa ideal sites for vaccine application. Moreover, vaccination through the mucosal immune system could induce effective systemic immune responses together with mucosal immunity in contrast to parenteral vaccination, which is a poor inducer of effective immunity at mucosal surfaces. Among mucosal vaccines, oral mucosal vaccines have the advantages of ease and low cost of vaccine administration. The oral mucosal immune system, however, is generally recognized as poorly immunogenic due to the frequent induction of tolerance against orally-introduced antigens. Consequently, a prerequisite for successful mucosal vaccination is that the orally introduced antigen should be transported across the mucosal surface into the mucosa-associated lymphoid tissue (MALT). In particular, M cells are responsible for antigen uptake into MALT, and the rapid and effective transcytotic activity of M cells makes them an attractive target for mucosal vaccine delivery, although simple transport of the antigen into M cells does not guarantee the induction of specific immune responses. Consequently, development of mucosal vaccine adjuvants based on an understanding of the biology of M cells has attracted much research interest. Here, we review the characteristics of the oral mucosal immune system and delineate strategies to design effective oral mucosal vaccines with an emphasis on mucosal vaccine adjuvants.

Influence of renal replacement therapy on immune response after one and two doses of the A(H1N1) pdm09 vaccine

Please cite this paper as: Quintana et al. (2012) Influence of renal replacement therapy on immune response after one and two doses of the A(H1N1) pdm09 vaccine. Influenza and Other Respiratory Viruses DOI: 10.1111/irv.12024.

Background  Patients with end‐stage renal disease have a reduced response to vaccination because of the general suppression of the immune system associated with uraemia.

Objectives  We evaluated the immune response and differential factors in the immunogenecity to an adjuvanted A(H1N1) pdm09 vaccine (Pandemrix^®) in four populations of renal patients after one and two doses of vaccine.

Patients Methods  151 patients were included in this study: 58 chronic haemodialysis patients, 52 renal allograft recipients, 14 peritoneal dialysis patients and 27 patients with advanced chronic kidney disease in preparation for kidney replacement therapy. Influenza‐specific antibody levels were measured by monitoring A(H1N1) pdm09 titres using a haemagglutination inhibition assay.

Results  The seroconversion rate at 42 days after two vaccine doses was 80% in the haemodialysis group, 64·9% in the renal allograft recipients group, 100% in the advanced chronic kidney disease group and 71·4% in the peritoneal dialysis group (P = 0·041).

Conclusions  Immune response to two doses of the influenza A H1N1 vaccine is dissimilar in the four renal conditions, confirming that seroprotection in pre‐dialysis, haemodialysis and peritoneal dialysis is similar to that in the general population vaccinated with one dose. In contrast, renal transplant recipients with good allograft function showed inadequate protection and triple immunosuppressive therapy including calcineurin inhibitors, mycophenolate and steroids negatively influenced seroconversion after vaccination in renal recipients.

Burden of respiratory syncytial virus infection in young children

Respiratory syncytial virus (RSV) is the most frequent and important cause of lower respiratory tract infection in infants and children. It is a seasonal virus, with peak rates of infection occurring annually in the cold season in temperate climates, and in the rainy season, as temperatures fall, in tropical climates. High risk groups for severe RSV disease include infants below six mo of age, premature infants with or without chronic lung disease, infants with hemodynamically significant congenital heart disease, infants with immunodeficiency or cystic fibrosis, and infants with neuromuscular diseases. Mortality rates associated with RSV infection are generally low in previous healthy infants (below 1%), but increase significantly in children with underlying chronic conditions and comorbidities. Following early RSV lower respiratory tract infection, some patients experience recurrent episodes of wheezing mimicking early childhood asthma with persistence of lung function abnormalities until adolescence. There is currently no RSV vaccine available, but promising candidate vaccines are in development. Palivizumab, a monoclonal RSV antibody that is the only tool for immunoprophylaxis in high-risk infants, lowers the burden of RSV infection in certain carefully selected patient groups.

Protective immunity using MPL-A and autoclaved Leishmania donovani as adjuvants along with a cocktail vaccine in murine model of visceral leishmaniasis

The current study is an extension of our previous study where we tested the protective efficacy of gp63 and Hsp70 against murine visceral leishmaniasis. The cocktail vaccine was combined with MPL-A and ALD adjuvants and the protection afforded by the three vaccines was compared. Inbred BALB/c mice were immunized twice at an interval of two weeks with the vaccine formulations. Two weeks after the booster, they were challenged with 10(7) promastigotes of Leishmania donovani and sacrificed on 30, 60 and 90 days post infection/challenge. The protective efficacy of vaccines was analyzed by assessment of the hepatic and splenic parasite burden and generation of cellular and humoral immune responses. The immunized animals revealed a significant reduction in parasite burden as compared to the infected controls. These animals also showed heightened DTH response, increased generation of IgG2a, IFN-γ and IL-2 by spleen cells. This was also accompanied by a decrease in the levels of IgG1 and IL-10. Mice immunized with gp63+Hsp70+MPL-A exhibited significantly greater protection in comparison to those immunized with gp63+Hsp70+ALD.

Public knowledge about hepatitis B-related issues in Korea

Hepatitis B infection is endemic in many parts of the world, including Korea. Basic knowledge of the hepatitis B virus by the public is a prerequisite for the development of a successful vaccination program. A survey was conducted in rural Korea to examine public knowledge of hepatitis B etiology, symptoms, transmission, risk factors and prevention. It was found that knowledge independently correlated with education and female sex, but that overall knowledge of hepatitis B was poor. The preferred information sources in order of preference were physicians, television and public health nurses. This information may be useful in designing public health education and vaccination programs in developing populations.

T lymphocyte immunity in host defence against Chlamydia trachomatis and its implication for vaccine development

Chlamydia trachomatis is an obligate intracellular bacterial pathogen that causes several significant human infectious diseases, including trachoma, urethritis, cervicitis and salpingitis, and is an important cofactor for transmission of human immunodeficiency virus. Until very recently, over three decades of research effort aimed at developing a C trachomatis vaccine had failed, due mainly to the lack of a precise understanding of the mechanisms for protective immunity. Although most studies concerning protective immunity to C trachomatis have focused on humoral immune responses, recent studies have clearly shown that T helper-1 (Th1)-like CD4 T cell-mediated immune responses play the dominant role in protective immunity. These studies suggest a paradigm for chlamydial immunity and pathology based on the concept of heterogeneity (Th1/Th2) in CD4 T cell immune responses. This concept for chlamydial immunity offers a rational template on which to base renewed efforts for development of a chlamydial vaccine that targets the induction of cell-mediated Th1 immune responses.

Passive protection of diabetic rats with antisera specific for the polysaccharide portion of the lipopolysaccharide isolated from Pseudomonas pseudomallei

Polyclonal and monoclonal antisera raised to tetanus toxoid-conjugated polysaccharide of lipopolysaccharide (lps) and purified lps of Pseudomonas pseudomallei that reacted with a collection of 41 strains of this bacterium from 23 patients are described. The common antigen recognized by these sera was within the polysaccharide component of the lps of the cells. The sera were specific for P pseudomallei in that none of 37 strains of other bacteria, including 20 Gram-negative and three Gram-positive species, were recognized, although cross-reaction occurred using the anticonjugate serum with some strains of Pseudomonas cepacia serotype A, a closely related bacterium. Passive protection studies using a diabetic rat model of P pseudomallei infection showed that partially purified rabbit polyclonal and mouse monoclonal antisera were protective when the median lethal dose was raised by four to five orders of magnitude. The wide distribution of the polysaccharide antigen among isolates of P pseudomallei used in this study and the protective role of antibody to the conjugated polysaccharide antigen suggest potential as a vaccine.

Mucosal vaccine adjuvants update

Mucosal vaccination, capable of inducing protective immune responses both in the mucosal and systemic immune compartments, has many advantages and is regarded as a blue ocean in the vaccine industry. Mucosal vaccines can offer lower costs, better accessability, needle-free delivery, and higher capacity of mass immunizations during pandemics. However, only very limited number of mucosal vaccines was approved for human use in the market yet. Generally, induction of immune responses following mucosal immunization requires the co-administration of appropriate adjuvants that can initiate and support the effective collaboration between innate and adaptive immunity. Classically, adjuvant researches were rather empirical than keenly scientific. However, during last several years, fundamental scientific achievements in innate immunity have been translated into the development of new mucosal adjuvants. This review focuses on recent developments in the concepts of adjuvants and innate immunity, mucosal immunity with special interest of vaccine development, and basic and applied researches in mucosal adjuvant.

The history of vaccination and current vaccination policies in Korea

There may be many reasons for the significant decrease in the incidence of the pediatric infectious diseases in modern Korea; this could be due to the improvement of sanitary facilities, significant growth of Korean economy, improvement of nutrition, development and dissemination of antibiotics and implantation of vaccination, and overall improvement of medical technology. The development of vaccination has been highlighted as a striking achievement of the modern medical sciences with new technologies in many fields of medicine. Since 1876, the method for vaccination has opened its new era by Suk-Young Jee, known as the Jenner in Korea who wrote a book about smallpox vaccination, and it led an opportunity to propagate the needs for the vaccination in Korea. There was a time when pediatric wards were full of patients with parasitic diseases and many vaccine-preventable diseases such as diphtheria, pertussis, Japanese B encephalitis, and poliomyelitis in 1950s-1960s. We do not see those infectious diseases that often any more in recent years. However, we still have patients with water-borne diseases and other communicable diseases related to increasing international travels. We just experienced the first pandemic influenza of the 21st century in 2009 and avian influenza is still a threat to humans in other parts of the world with an unpredictable potential of pandemicity. In addition, we have tough battles with emerging antibiotic resistance in many strains of bacteria and increased opportunistic infections due to improvement of medical technology involving more aggressive treatment modality and use of medical devices. Researches in many areas are under way and we hope that some of them may be preventable and decreased with a development of new vaccines in the future.

Animal models for the study of hepatitis C virus infection and replication

Hepatitis C virus (HCV) hepatitis, initially termed non-A, non-B hepatitis, has become one of the leading causes of cirrhosis and hepatocellular carcinoma worldwide. With the help of animal models, our understanding of the virus has grown substantially from the time of initial discovery. There is a paucity of available animal models for the study of HCV, mainly because of the selective susceptibility limited to humans and primates. Recent work has focused modification of animals to permit HCV entry, replication and transmission. In this review, we highlight the currently available models for the study of HCV including chimpanzees, tupaia, mouse and rat models. Discussion will include methods of model design as well as the advantages and disadvantages of each model. Particular focus is dedicated to knowledge of pathophysiologic mechanisms of HCV infection that have been elucidated through animal studies. Research within animal models is critically important to establish a complete understanding of HCV infection, which will ultimately form the basis for future treatments and prevention of disease.

Epitope mapping of gp350/220 conserved domain of epstein barr virus to develop nasopharyngeal carcinoma (npc) vaccine

Nasopharyngeal carcinoma (NPC) is a malignant tumor in the nasopharyngeal epithelial cells that caused by many factors, one of which is the viral infection of EBV (Epstein Barr Virus). The standard treatments to cure NPC still have not been encouraging. The prevention through vaccination is an effective way to stop the disease. However, EBV vaccine being able to cover all variants of virus is still not available yet. Therefore, we identified the conserved region of glycoprotein 350/220 of EBV which has immunogenic and antigenic properties. The glycoprotein 350/220 is viral surface protein responsible to bind CR2 receptor, mediated EBV to enter the host cell. The conserved domain is crucial for EBV in infecting host cells. Further, by blocking CR2 binding domain of gp350/220 using antibody will inhibit EBV's spreading, and provoke an immune system to eliminate the virus in a patient. Glycoprotein 350/220 from all variants of Epstein-Barr virus was retrieved from NCBI. The conserved domain of gp350/220 was identified by aligning the protein sequences and structures. The polymorphic structure was used as a template for docking analysis to identify the resemblance of amino acid from polymorphic variants of gp350/220 that binds CR2. The epitope mapping of gp350/220 was done by Discotope BepiPred method. The result revealed that the conserved region of gp350/220 was predicted to have an epitope, QNPVYLIPETVPYIKWDNC residue, and it does not have any similarities to the human's cell surface protein. Therefore, it can be used as a reference to develop vaccine to prevent NPC.

Differentiating the wild from the attenuated during a measles outbreak

In the midst of a local measles outbreak, a recently immunized child was investigated for a new-onset measles-type rash. Nucleic acid testing identified that a vaccine-type measles virus was being shed in the urine. Clinically differentiating measles from a nonmeasles rash is challenging, but can be supported by a thorough medical history evaluation. Rashes are expected to occur after immunization; nucleic acid testing can be used when it is difficult to differentiate between wild and attenuated strains.

Consensus recommendation for meningococcal disease prevention in children and adolescents in the Middle East region

Facing the availability of the new generation of quadrivalent meningococcal conjugate vaccines (Menveo®, Menactra® and others pending for license) and their recent implementation in Saudi Arabia, experts from 11 countries of the Middle East region met at a “Meningococcal Leadership Forum” (MLF), which took place in May 2010 in Dubai. The participants of the conference discussed the importance of introducing the concept of conjugate vaccines – especially for children and adolescents – and elaborated a consensus recommendation to support healthcare professionals and decision makers with their expertise. In experts’ opinion, conjugate vaccines are the best choice for the prevention of meningococcal disease caused by serogroups A, C, W-135 and Y. As quadrivalent meningococcal conjugate vaccines are registered and available in the Middle East region, they should replace plain polysaccharide vaccines and be integrated in pediatric and adolescent vaccination schedules, including infant vaccination concomitantly with basic EPI vaccines when licensed.

Hepatitis B: Epidemiology and prevention in developing countries

Hepatitis B virus (HBV) infection is a serious global public health problem. The infection may be transmitted through sexual intercourse, parenteral contact or from an infected mother to the baby at birth and, if contracted early in life, may lead to chronic liver disease, including cirrhosis and hepatocellular carcinoma. On the basis of the HBV carrier rate, the world can be divided in 3 regions of high, medium and low endemicity. The major concern is about high endemicity countries, where the most common route of infection remains vertical transmission from mother to child. Screening of all pregnant women and passive immunization with human hepatitis B immunoglobulin are not affordable for many developing countries. The infection rate can be reduced by modifying behavior, improving individual education, testing all blood donations, assuring asepsis in clinical practice and screening all pregnant women. However, availability of a safe and efficacious vaccine and adoption of appropriate immunization strategies are the most effective means to prevent HBV infection and its consequences. The unsolved problem for poorest countries, where the number of people currently infected is high, is the cost of the vaccine. A future challenge is to overcome the social and economic hurdles of maintaining and improving a prevention policy worldwide to reduce the global burden of the disease.

Hepatitis A: Epidemiology and prevention in developing countries

Hepatitis A is the most common form of acute viral hepatitis in the world. Major geographical differences in endemicity of hepatitis A are closely related to hygienic and sanitary conditions and other indicators of the level of socioeconomic development. The anti-hepatitis A virus (HAV) seroprevalence rate is presently decreasing in many parts of the world, but in less developed regions and in several developing countries, HAV infection is still very common in the first years of life and seroprevalence rates approach 100%. In areas of intermediate endemicity, the delay in the exposure to the virus has generated a huge number of susceptible adolescents and adults and significantly increased the average age at infection. As the severity of disease increases with age, this has led to outbreaks of hepatitis A. Several factors contribute to the decline of the infection rate, including rising socioeconomic levels, increased access to clean water and the availability of a hepatitis A vaccine that was developed in the 1990s. For populations with a high proportion of susceptible adults, implementing vaccination programs may be considered. In this report, we review available epidemiological data and implementation of vaccination strategies, particularly focusing on developing countries.

Porcine reproductive and respiratory syndrome virus vaccines: Immunogenicity, efficacy and safety aspects

Porcine reproductive and respiratory syndrome virus (PRRSV) infection is the leading cause of economic casualty in swine industry worldwide. The virus can cause reproductive failure, respiratory disease, and growth retardation in the pigs. This review deals with current status of commercial PRRS vaccines presently used to control PRRS. The review focuses on the immunogenicity, protective efficacy and safety aspects of the vaccines. Commercial PRRS modified-live virus (MLV) vaccine elicits delayed humoral and cell-mediated immune responses following vaccination. The vaccine confers late but effective protection against genetically homologous PRRSV, and partial protection against genetically heterologous virus. The MLV vaccine is of concern for its safety as the vaccine virus can revert to virulence and cause diseases. PRRS killed virus (KV) vaccine, on the other hand, is safe but confers limited protection against either homologous or heterologous virus. The KV vaccine yet helps reduce disease severity when administered to the PRRSV-infected pigs. Although efforts have been made to improve the immunogenicity, efficacy and safety of PRRS vaccines, a better vaccine is still needed in order to protect against PRRSV.

Immune Responses to pneumococcal vaccines in children and adults: Rationale for age-specific vaccination

Streptococcus pneumoniae is a significant human pathogen and currently available pneumococcal vaccines are designed to elicit anti-capsule antibodies. The 23-valent polysaccharide vaccine has been used in older adults for many years whereas 7-, 10-, and 13-valent pneumococcal conjugate vaccines have only been used commonly for young children in the last decade. In addition to their high protective efficacy among children, the use of conjugate vaccines in young children has had a number of additional effects, including production of a serotype shift and providing new herd immunity to adults. The immunogenicity of both of these types of vaccines can be determined by using an ELISA assay to measure antibody levels or an opsonophagocytosis assay to assess opsonic function. As these assays have improved over time, awareness of the analytical limitations of older studies has grown. While the 23-valent vaccine is effective among young adults, it is less effective among elderly adults. Aging-associated ineffectiveness may be due to aging-dependent changes in the antibody repertoire and/or a reduction in IgM antibody production associated with aging-dependent changes in B cell subpopulations. The immunologic basis of aging-associated immune defects thus remains an active area of research.

Viral Vaccines in India: An Overview

Viruses cause a large number of diseases in humans, some of which are fatal, while others are highly debilitating. A majority of viral diseases attack infants and young children, while others strike people in their prime. Development of preventive measures against viral diseases is, therefore, of paramount importance. Vaccination is the most cost-effective medical intervention for preventing mortality and morbidity against infectious diseases. A number of effective and safe vaccines are currently available against several viral diseases of significant medical importance. Many of these manufactured in India, are at par with international standards and are affordable. For many other viral diseases, for which vaccines are currently not available, research is underway at various national laboratories, as well as in the private sector companies in India. The present overview highlights the various vaccine preventable viral diseases that are of special importance to India and aims to provide a glimpse of the various vaccines that are currently available, or are under development in India.

Management of breast cancer by vaccine: fact or fiction

Breast cancer (BC) is the most common malignancy (75–80%) among women. Options for management of BC are multivariate. Available modalities include surgery, radiotherapy, chemotherapy and hormone therapy. Despite availability of improved therapeutic adjuncts, mortality from BC is 40%. Vaccination strategies against BC are emerging as a viable alternative. This review highlights the available results of this emerging therapeutic strategy.

Construction of an Expression Vector Containing Mtb72F of Mycobacterium tuberculosis

OBJECTIVE

Despite using the Bacille Calmette Guerin (BCG) vaccine, tuberculosis (TB) is still a worldwide disease that kills 2-3 million people each year. Developing a new and more effective vaccine is one way to possibly reduce the morbidity and mortality of TB. The Mtb72F vaccine is one of the important subunit vaccines applied in human clinical trials. In this study, we have constructed an expression vector that contains the Mtb72F fragment with some new modifications.

MATERIALS AND METHODS

In this experimental study, Mtb32N and Mtb39 fragments were amplified by polymerase chain reaction (PCR) using specific primers and inserted into pET21b\Mtb32C. Colony-PCR, restriction enzyme analysis, and DNA sequencing were used to confirm the accuracy of the cloning. We used Western blot to verify the desired protein expression.

RESULTS

The amplified fragments showed the desired size in PCR and digestion methods, and protein expression was confirmed using a monoclonal antibody.

CONCLUSION

Our modification made it possible to insert another gene or gene fragments into the Mtb72F vector for developing new constructs. In addition, our data has shown that the placement of the histidine tag in the carboxyl- (C-) or amino- (N-) terminal part of a protein may influence protein expression and/or stability.

Ear necrosis syndrome in weaning pigs associated with PCV2 infection: A case report

Porcine necrotic ear syndrome (PNES) in pigs has been reported as an increasing health problem in many countries with intensive pig farming. The etiology of this disease is complex and the presumed triggering factors can be divided into infectious and non-infectious agents. The present report describes a case of Porcine Circovirus type 2 (PCV2), infection associated with lesions of PNES at the weaning stage of a farrow-to-finish pig farm. Approximately 35% of weaners (1-3 weeks after weaning) presented clinical symptoms similar to Post-weaning Multisystemic Wasting Syndrome (PMWS). About 2-3 weeks after weaning the first lesions of PNES occurred in approximately 20% of pigs, resulting in a significant health problem characterized by poor growth or severe wasting and finally mortality up to 15% in some batches. Moreover, approximately 5% of survived weaners, during growing / finishing stage, presented poor growth and secondary co-infections that lead to death. The present study based on the clinical signs, serological and pathological examinations, indicates that weaners suffered by sub-acute PCV2 infection resulting in PMWS associated with PNES. The lesions of PNES were initially observed at the same period (4-8 weeks of age) with the higher seroprevalence of PCV2 infection. Metaphylaxis of this case included intramuscular injection of florfenicol for the treatment and control of skin lesions and respiratory signs. Moreover, piglets were vaccinated against PCV2. In conclusion, sub-acute PCV2 infection could be included in triggering factors PNES in weaners. The mass vaccination against PCV2 of infected piglets might be effective in reduction of clinical signs and losses of PNES in cases of PCV2 infection associated with PNES.

Comparison of in vivo Adjuvanticity of Liposomal PO CpG ODN with Liposomal PS CpG ODN: Soluble Leishmania Antigens as a Model

OBJECTIVES

CpG oligodeoxynucleotides (CpG ODNs) have been shown to have potent immunostimulatory adjuvant activity for a wide range of antigens. Due to susceptibility of phosphodiester CpG ODNs (PO CpG) to nuclease degradation, nuclease-resistant phosphorothioate CpG ODNs (PS CpG) were currently utilized in an in vivo model. In this study, according to some recently reported drawbacks with PS CpG, the adjuvant potential of liposomal PO CpG as a substitute for PS CpG was evaluated.

MATERIALS AND METHODS

Soluble Leishmania antigens (SLA) as a model antigen and distearoylphosphatidylcoline (DSPC) as a neutral lipid were employed to prepare liposomes. Susceptible BALB/c mice received buffer, SLA, Lip-SLA, Lip-SLA-PS CpG, Lip-SLA-PO CpG, SLA+PS CpG, or SLA+PO CpG subcutaneously 3 times with 3 weeks intervals and then were challenged with Leishmania major's live promastigotes. Blood and spleen samples were analyzed to determine the level and type of antibodies and cytokines. The number of live parasites in the spleen of immunized mice was determined. Moreover, the lesion size progress was assessed weekly by footpad swelling measurement.

RESULTS

The results showed that mice immunized with Lip-SLA-PS CpG or Lip-SLA-PO CpG developed a significantly smaller footpad swelling, higher level of anti SLA IgG antibodies before and after challenge, and lower spleen parasite burden compared with the control groups. However, there was no significant difference between mice received Lip-SLA-PS CpG and those received Lip-SLA-PO CpG.

CONCLUSION

The results demonstrated that liposomal PO CpG ODN could be used instead of PS CpG ODN to overcome the possible drawbacks.

Immunogenicity of MHC Class I Peptides Derived from Leishmania mexicana Gp63 in HLA-A2.1 Transgenic (HHDII) and BALB/C Mouse Models

BACKGROUND

Leishmania is an intracellular parasite infecting humans and many wild and domestic animals. Recent studies have suggested an important role for cytotoxic T cells against Leishmania. Peptide-based vaccines targeting short sequences derived from known immunogenic proteins have been shown to elicit cellular immune responses against disparate pathogens.

METHODS

We predicted four HLA-A2 peptides derived from L. mexican/major gp63 and tested these in HHD II mice, as well as four peptides for mouse MHC class I from the same proteins tested in BALB/ mice.

RESULTS

The results revealed immunogenicity for three of the four peptides predicted for HLA-A2. Immunisation with these peptides, along with IFA, induced CTL responses detected by standard 4-hour cytotoxicity assay and significantly upregulated the production of IFN-γ. When HHDII mice were injected IM with L. mexicana gp63 cDNA and splenocytes were restimulated with blasts loaded with the immunogenic peptides, two of the peptides were able to induce significant level of IFN-γ detected by ELISA. None of the peptides predicted for Balb/c mouse MHC class I elicited CTL activity or significantly upregulated the IFN-γ.

CONCLUSION

The results may help in developing a peptide-based vaccine, which can be applied alone or in combination with drugs against Leishmania.