The duration of Chlamydia muridarum genital tract infection and associated chronic pathological changes are reduced in IL-17 knockout mice but protection is not increased further by immunization

IL-17 is believed to be important for protection against extracellular pathogens, where clearance is dependent on neutrophil recruitment and local activation of epithelial cell defences. However, the role of IL-17 in protection against intracellular pathogens such as Chlamydia is less clear. We have compared (i) the course of natural genital tract C. muridarum infection, (ii) the development of oviduct pathology and (iii) the development of vaccine-induced immunity against infection in wild type (WT) BALB/c and IL-17 knockout mice (IL-17-/-) to determine if IL-17-mediated immunity is implicated in the development of infection-induced pathology and/or protection. Both the magnitude and duration of genital infection was significantly reduced in IL-17-/- mice compared to BALB/c. Similarly, hydrosalpinx was also greatly reduced in IL-17-/- mice and this correlated with reduced neutrophil and macrophage infiltration of oviduct tissues. Matrix metalloproteinase (MMP) 9 and MMP2 were increased in WT oviducts compared to IL-17-/- animals at day 7 post-infection. In contrast, oviducts from IL-17-/- mice contained higher MMP9 and MMP2 at day 21. Infection also elicited higher levels of Chlamydia-neutralizing antibody in serum of IL-17-/- mice than WT mice. Following intranasal immunization with C. muridarum Major Outer Membrane Protein (MOMP) and cholera toxin plus CpG adjuvants, significantly higher levels of chlamydial MOMP-specific IgG and IgA were found in serum and vaginal washes of IL-17-/- mice. T cell proliferation and IFNγ production by splenocytes was greater in WT animals following in vitro re-stimulation, however vaccination was only effective at reducing infection in WT, not IL-17-/- mice. Intranasal or transcutaneous immunization protected WT but not IL-17-/- mice against hydrosalpinx development. Our data show that in the absence of IL-17, the severity of C. muridarum genital infection and associated oviduct pathology are significantly attenuated, however neither infection or pathology can be reduced further by vaccination protocols that effectively protect WT mice.

Factors influencing the impact of primary and secondary prevention strategies for cervical cancer among Queensland women

Since the introduction of the National Human Papillomavirus Vaccine Program (NHPVP) in 2007, few studies have assessed women's knowledge, beliefs and attitudes towards cervical screening and human papillomavirus (HPV) vaccination in Australia. It is imperative to ascertain this, as substantial changes are anticipated to the National Cervical Screening Program (NCSP) through a process called 'the Renewal', to ensure any changes that are introduced will be acceptable and well understood by women. The objectives of this study were to describe Queensland women's current knowledge of cervical cancer/screening and HPV, their beliefs and attitudes towards Pap smears and the HPV vaccine and seek their advice on effective methods for communicating changes to the NCSP in their communities. This research was a descriptive-exploratory study that incorporated a combination of qualitative and quantitative methods within the context of the Health Belief Model (HBM). A computer-assisted telephone interview (CATI) survey of 1002 Queensland women was conducted in Phase 1 of the study. During Phase 2 of the study, 23 focus groups were conducted throughout Queensland to gather in-depth information about women's knowledge, awareness and acceptance about cervical cancer prevention strategies. This study found high levels of awareness of HPV (over 60%) and the HPV vaccine (over 86%) amongst Queensland women. However, it also identified considerable uncertainty amongst participants about perceived susceptibility to cervical cancer, especially, the link between cervical cancer, HPV and sexual activity. Women also had limited understanding of the benefit of the Pap smear as a preventative strategy, with many women thinking the main purpose of the Pap smear was for the early detection of cancer. Despite high awareness of HPV, women participating in this study also had significant knowledge deficits about their susceptibility to HPV and the severity of HPV infection. Queensland women had high levels of awareness of the HPV vaccine, which was most commonly via the media. High acceptance of the HPV vaccine was found amongst participants although awareness of the full benefits of vaccination was not evident with little acknowledgement that the quadrivalent vaccine used in the NHPVP would also prevent genital warts. Extensive barriers to having Pap smears, including physical and psychological discomfort, were identified and the most common barriers to vaccination were concerns about side effects and a lack of information upon which to make a decision about consent. Women described enablers for screening participation, such as reminder systems and practitioner characteristics, and expressed positive views towards self collected testing as an enabler, particularly for women who did not attend screening. As this study was conducted with Queensland women it may therefore not be representative of women from other parts of Australia and as participants were more likely to report they were regular screeners than Queensland women overall, these results may not be representative of women least likely to participate in cervical screening. The use of self-reported cervical screening history may also have led to over-reporting of screening status and previous abnormalities by participants. This study reveals significant gaps in Queensland women's knowledge that require effective communication strategies to address. Recommendations from this study highlight the need for increased community education to raise awareness about primary and secondary cervical cancer prevention strategies, training of cervical screening providers in sensitive examination techniques, a reduction in costs associated with screening, the exploration of alternative service models and communication plans that incorporate methods women trust and recommend for disseminating information about changes to the NCSP. This study is the first large study to explore women's perceptions of the Pap smear and barriers to screening, their knowledge about HPV and their attitudes towards the HPV vaccine in Queensland, since the introduction of the NHPVP. It highlights considerable uncertainty about many aspects of cervical cancer and primary and secondary prevention strategies available in Australia and identified many barriers to cervical screening and concerns about HPV vaccination. These knowledge gaps and barriers need to be taken into account and addressed within the context of anticipated changes to the NCSP to ensure benefits are maximised for women in future primary and secondary cervical cancer prevention strategies in the Australian context.

Immunisation coverage in Australian Indigenous children : time to move the goal posts

Childhood immunisation coverage reported at 12 to <15 months and 2 years of age, may mask deficiencies in the timeliness of vaccines designed to protect against diseases in infancy. This study aimed to evaluate immunisation timeliness in Indigenous infants in the Northern Territory, Australia. Coverage was analysed at the date children turned 7, 13 and 18 months of age. By 7 months of age, 45.2% of children had completed the recommended schedule, increasing to 49.5% and 81.2% at 13 and 18 months of age, respectively. Immunisation performance benchmarks must focus on improving the timeliness in these children in the first year of life.

Effectiveness of 7-valent pneumococcal conjugate vaccine against radiologically diagnosed pneumonia in indigenous infants in Australia

Objective To evaluate the effectiveness of the 7-valent pneumococcal conjugate vaccine (PCV7) in preventing pneumonia, diagnosed radiologically according to World Health Organization (WHO) criteria, among indigenous infants in the Northern Territory of Australia. Methods We conducted a historical cohort study of consecutive indigenous birth cohorts between 1 April 1998 and 28 February 2005. Children were followed up to 18 months of age. The PCV7 programme commenced on 1 June 2001. All chest X-rays taken within 3 days of any hospitalization were assessed. The primary endpoint was a first episode of WHO-defined pneumonia requiring hospitalization. Cox proportional hazards models were used to compare disease incidence. Findings There were 526 pneumonia events among 10 600 children - an incidence of 3.3 per 1000 child-months; 183 episodes (34.8%) occurred before 5 months of age and 247 (47.0%) by 7 months. Of the children studied, 27% had received 3 doses of vaccine by 7 months of age. Hazard ratios for endpoint pneumonia were 1.01 for 1 versus 0 doses; 1.03 for 2 versus 0 doses; and 0.84 for 3 versus 0 doses. Conclusion There was limited evidence that PCV7 reduced the incidence of radiologically confirmed pneumonia among Northern Territory indigenous infants, although there was a non-significant trend towards an effect after receipt of the third dose. These findings might be explained by lack of timely vaccination and/or occurrence of disease at an early age. Additionally, the relative contribution of vaccine-type pneumococcus to severe pneumonia in a setting where multiple other pathogens are prevalent may differ with respect to other settings where vaccine efficacy has been clearly established.

Oral immunization with a novel lipid-based adjuvant protects against genital Chlamydia infection

Oral immunization is attractive as a delivery route because it is needle-free and useful for rapid mass vaccination programs to target pandemics or bioterrorism. This potential has not been realized for human vaccination, due to the requirement of large antigen doses and toxic (to humans) adjuvants to overcome the induction of oral tolerance and potential degradation of antigens in the stomach. To date, only oral vaccines based on live attenuated organisms have been approved for human use. In this study we describe the use of a lipid-based delivery system/adjuvant, Lipid C, for oral immunization to protect mice against genital tract chlamydial infection. Lipid C is formulated from food-grade purified and fractionated triglycerides. Bacterial shedding following vaginal challenge with Chlamydia muridarum was reduced by 50% in female mice orally immunized with the chlamydial major outer membrane protein (MOMP) formulated in Lipid C, protection equivalent to that seen in animals immunized with MOMP admixed with both cholera toxin (CT) and CpG oligodeoxynucleotides (CpG-ODN). Protection was further enhanced when MOMP, CT and CpG were all combined in the Lipid C matrix. Protection correlated with production of gamma interferon (IFN) by splenic T cells, a serum MOMP-specific IgG response and low but detectable levels of MOMP-specific IgA in vaginal lavage.

Transcutaneous immunization with a novel lipid-based adjuvant protects against Chlamydia genital and respiratory infections

Mucosal adjuvants are important to overcome the state of immune tolerance normally associated with mucosal delivery and to enhance adaptive immunity to often-weakly immunogenic subunit vaccine antigens. Unfortunately, adverse side effects of many experimental adjuvants limit the number of adjuvants approved for vaccination. Lipid C is a novel, non-toxic, lipid oral vaccine-delivery formulation, developed originally for oral delivery of the live Mycobacterium bovis Bacille Calmette-Guerin (BCG) vaccine. In the present study, murine models of chlamydial respiratory and genital tract infections were used to determine whether transcutaneous immunization (TCI) with Lipid C-incorporated protein antigens could elicit protective immunity at the genital and respiratory mucosae. BALB/c mice were immunized transcutaneously with Lipid C containing the chlamydial major outer membrane protein (MOMP), with and without addition of cholera toxin and CpG-ODN 1826 (CT/CpG). Both vaccine combinations induced mixed cell-mediated and mucosal antibody immune responses. Immunization with Lipid C-incorporated MOMP (Lipid C/MOMP), either alone or with CT/CpG resulted in partial protection following live challenge with Chlamydia muridarum as evidenced by a significant reduction in recoverable Chlamydia from both the genital secretions and lung tissue. Protection induced by immunization with Lipid C/MOMP alone was not further enhanced by the addition of CT/CpG. These results highlight the potential of Lipid C as a novel mucosal adjuvant capable of targeting multiple mucosal surfaces following TCI. Protection at both the respiratory and genital mucosae was achieved without the requirement for potentially toxic adjuvants, suggesting that Lipid C may provide a safe effective mucosal adjuvant for human vaccination.

Intranasal immunization with C. muridarum major outer membrane protein (MOMP) and cholera toxin elicits local production of neutralising IgA in the prostate

Successful control of sexually transmitted diseases (STDs) through vaccination will require the development of vaccine strategies that target protective immunity to both the female and male reproductive tracts (MRT). In the male, the immune privileged nature of the male reproductive tract provides a barrier to entry of serum immunoglobulins into the male reproductive ducts, thereby preventing the induction of protective immunity using conventional injectable vaccination techniques. In this study we investigated the potential of intranasal (IN) immunization to elicit anti-chlamydial immunity in BALB/c male mice. Intranasal immunization with Chlamydia muridarum major outer membrane protein (MOMP) admixed with cholera toxin (CT) resulted in high levels of MOMP-specific IgA in prostatic fluids (PF) and MOMP-specific IgA-secreting cells in the prostate. Prostatic fluid IgA inhibited in vitro infection of McCoy cells with C. muridarum. Using RT-PCR we also show that mRNA for the polymeric immunoglobulin receptor (PIgR), which transports IgA across mucosal epithelia, is expressed only in the prostate but not in other regions of the male reproductive ducts upstream of the prostate. These data suggest that using intranasal immunization to target IgA to the prostate may protect males against STDs while at the same time maintaining the state of immune privilege within the MRT.

STI-GMaS : an open-source environment for simulation of sexually-transmitted infections

Background Sexually-transmitted pathogens often have severe reproductive health implications if treatment is delayed or absent, especially in females. The complex processes of disease progression, namely replication and ascension of the infection through the genital tract, span both extracellular and intracellular physiological scales, and in females can vary over the distinct phases of the menstrual cycle. The complexity of these processes, coupled with the common impossibility of obtaining comprehensive and sequential clinical data from individual human patients, makes mathematical and computational modelling valuable tools in developing our understanding of the infection, with a view to identifying new interventions. While many within-host models of sexually-transmitted infections (STIs) are available in existing literature, these models are difficult to deploy in clinical/experimental settings since simulations often require complex computational approaches. Results We present STI-GMaS (Sexually-Transmitted Infections – Graphical Modelling and Simulation), an environment for simulation of STI models, with a view to stimulating the uptake of these models within the laboratory or clinic. The software currently focuses upon the representative case-study of Chlamydia trachomatis, the most common sexually-transmitted bacterial pathogen of humans. Here, we demonstrate the use of a hybrid PDE–cellular automata model for simulation of a hypothetical Chlamydia vaccination, demonstrating the effect of a vaccine-induced antibody in preventing the infection from ascending to above the cervix. This example illustrates the ease with which existing models can be adapted to describe new studies, and its careful parameterisation within STI-GMaS facilitates future tuning to experimental data as they arise. Conclusions STI-GMaS represents the first software designed explicitly for in-silico simulation of STI models by non-theoreticians, thus presenting a novel route to bridging the gap between computational and clinical/experimental disciplines. With the propensity for model reuse and extension, there is much scope within STI-GMaS to allow clinical and experimental studies to inform model inputs and drive future model development. Many of the modelling paradigms and software design principles deployed to date transfer readily to other STIs, both bacterial and viral; forthcoming releases of STI-GMaS will extend the software to incorporate a more diverse range of infections.

Human CD141(+) (BDCA-3)(+) dendritic cells (DCs) represent a unique myeloid DC subset that cross-presents necrotic cell antigens

The characterization of human dendritic cell (DC) subsets is essential for the design of new vaccines. We report the first detailed functional analysis of the human CD141(+) DC subset. CD141(+) DCs are found in human lymph nodes, bone marrow, tonsil, and blood, and the latter proved to be the best source of highly purified cells for functional analysis. They are characterized by high expression of toll-like receptor 3, production of IL-12p70 and IFN-beta, and superior capacity to induce T helper 1 cell responses, when compared with the more commonly studied CD1c(+) DC subset. Polyinosine-polycytidylic acid (poly I:C)-activated CD141(+) DCs have a superior capacity to cross-present soluble protein antigen (Ag) to CD8(+) cytotoxic T lymphocytes than poly I:C-activated CD1c(+) DCs. Importantly, CD141(+) DCs, but not CD1c(+) DCs, were endowed with the capacity to cross-present viral Ag after their uptake of necrotic virus-infected cells. These findings establish the CD141(+) DC subset as an important functionally distinct human DC subtype with characteristics similar to those of the mouse CD8 alpha(+) DC subset. The data demonstrate a role for CD141(+) DCs in the induction of cytotoxic T lymphocyte responses and suggest that they may be the most relevant targets for vaccination against cancers, viruses, and other pathogens.

Phage library screening for the rapid identification and in vivo testing of candidate genes for a DNA vaccine against Mycoplasma mycoides subsp. mycoides small colony biotype

A new strategy for rapidly selecting and testing genetic vaccines has been developed, in which a whole genome library is cloned into a bacteriophage λ ZAP Express vector which contains both prokaryotic (Plac) and eukaryotic (PCMV) promoters upstream of the insertion site. The phage library is plated on Escherichia coli cells, immunoblotted, and probed with hyperimmune and/or convalescent-phase antiserum to rapidly identify vaccine candidates. These are then plaque purified and grown as liquid lysates, and whole bacteriophage particles are then used directly to immunize the host, following which PCMV-driven expression of the candidate vaccine gene occurs. In the example given here, a semirandom genome library of the bovine pathogen Mycoplasma mycoides subsp. mycoides small colony (SC) biotype was cloned into λ ZAP Express, and two strongly immunodominant clones, λ-A8 and λ-B1, were identified and subsequently tested for vaccine potential against M. mycoides subsp. mycoides SC biotype-induced mycoplasmemia. Sequencing and immunoblotting indicated that clone λ-A8 expressed an isopropyl-β-d-thiogalactopyranoside (IPTG)-inducible M. mycoides subsp. mycoides SC biotype protein with a 28-kDa apparent molecular mass, identified as a previously uncharacterized putative lipoprotein (MSC_0397). Clone λ-B1 contained several full-length genes from the M. mycoides subsp. mycoides SC biotype pyruvate dehydrogenase region, and two IPTG-independent polypeptides, of 29 kDa and 57 kDa, were identified on immunoblots. Following vaccination, significant anti-M. mycoides subsp. mycoides SC biotype responses were observed in mice vaccinated with clones λ-A8 and λ-B1. A significant stimulation index was observed following incubation of splenocytes from mice vaccinated with clone λ-A8 with whole live M. mycoides subsp. mycoides SC biotype cells, indicating cellular proliferation. After challenge, mice vaccinated with clone λ-A8 also exhibited a reduced level of mycoplasmemia compared to controls, suggesting that the MSC_0397 lipoprotein has a protective effect in the mouse model when delivered as a bacteriophage DNA vaccine. Bacteriophage-mediated immunoscreening using an appropriate vector system offers a rapid and simple technique for the identification and immediate testing of putative candidate vaccines from a variety of pathogens.

Mothers and health promotion : closing the gap for 100% measles immunization in North Vietnam

Objectives This study aims to develop a better understanding of mothers’ knowledge, understanding, and attitude towards children’s measles immunization and explore the relationship between mothers’ understanding of measles immunization and health promotion programs in North Vietnam. Methods Semi-structured interviews were conducted with 15 mothers of children aged 1 or 6 years old between 2006 and 2010 in two provinces in North Vietnam. Ten interviews were transcribed and analysed to explore themes while other five interviews were cross-referenced for congruency. Among the ten mothers whose interviews were analysed, there were five mothers whose children received the full measles immunization schedule (two doses) and five mothers whose children received one or none of measles vaccination. Results Mothers had different levels of understanding and a strong positive attitude towards measles immunization. Mothers considered health officers at the commune health centres who played an important role in the promotion of measles immunization, as the main source of information. The relationship between the mother’s understanding about measles immunization and health promotion programs was found to be both positive and negative. Conclusion Mothers whose children received the full measles immunization schedule paid more attention to measles immunization and health promotion programs compared with mothers whose children received one or none of measles vaccination. Mothers’ misunderstanding about the measles immunization schedule was the main reason for choosing not to receive the measles immunizations. These findings help to improve communication with mothers about measles immunization and close the gap for 100% measles immunization in North Vietnam.

Preparing Queensland pharmacists to vaccinate – Australia’s first pharmacists immunisation pilot

In November 2013, the Queensland Department of Health announced its intention to pilot pharmacists vaccination for influenza in the 2014 Flu season. The Pharmaceutical Society of Australia Queensland Branch was tasked with development of an appropriate training program for the pilot.

Australia’s first Pharmacist Immunisation Pilot - who did pharmacists inject?

The Queensland Pharmacist Immunisation Pilot is Australia’s first to allow pharmacists vaccination. The pilot ran between April 1st 2014 and August 31st 2014, with pharmacists administering influenza vaccination during the flu season. METHODS Participant demographics and previous influenza vaccination experiences were recorded using GuildCare software. Participants also completed a ‘post-vaccination satisfaction survey’ following their influenza vaccination. RESULTS A total of 11,475 participant records were analysed. Females accounted for 63% of participants, with the majority of participants aged between 45 – 64 years (53%). Overall, 49% of participants had been vaccinated before, the majority at a GP clinic (60%). Most participants reported receiving their previous influenza vaccination from a nurse (61%). Interestingly, 1% thought a pharmacist had administered their previous vaccination, while 7% were unsure which health professional had administer it. It was also of note that approximately 10% of all participants were eligible to receive a free vaccination from the National Immunisation Program, but still opted to receive their vaccine in a pharmacy. Over 8,000 participants took part in the post-vaccination survey, 93% were happy to receive their vaccination from a pharmacy in the future while 94% would recommend this service to other people. The remaining 7% and 6% respectively had omitted to fill in those questions. DISCUSSION Participants were overwhelmingly positive in their response to the pharmacist vaccination pilot. These findings have helped pave the way for expanding the scope of practice for pharmacists with the aim to increase vaccination rates across the state.

Using DNA as a drug - bioprocessing and delivery strategies

DNA may take a leading role in a future generation of blockbuster therapeutics. DNA has inherent advantages over other biomolecules such as protein, RNA and virus-like particles including safety, production simplicity and higher stability at ambient temperatures. Vaccination is the principal measure for preventing influenza and reducing the impact of pandemics; however, vaccines take up to 8-9 months to produce, and the global production capacity is woefully low. With production times as short as 2 weeks, improved safety and stability, bioprocess engineering developments, and the ability to perform numerous therapeutic roles, DNA has the potential to meet the demands of emerging and existing diseases. DNA is experiencing sharp growths in demand as indicated by its use in gene therapy trials and DNA vaccine related patents. Of particular interest for therapeutic use is plasmid DNA (pDNA), a form of non-genomic DNA that makes use of cellular machinery to express proteins or antigens. The production stages of fermentation and downstream purification are considered in this article. Forward looking approaches to purifying and delivering DNA are reported, including affinity chromatography and nasal inhalation. The place that pDNA may take in the preparation for and protection against pandemics is considered. If DNA therapeutics and vaccines prove to be effective, the ultimate scale of production will be huge which shall require associated bioprocess engineering research and development for purification of this large, unique biomolecule.

Inorganic-organic composite particle as a staged delivery platform for plasmid DNA-based biopharmaceuticals

Infectious diseases such as SARS, influenza and bird flu may spread exponentially throughout communities. In fact, most infectious diseases remain major health risks due to the lack of vaccine or the lack of facilities to deliver the vaccines. Conventional vaccinations are based on damaged pathogens, live attenuated viruses and viral vectors. If the damage was not complete, the vaccination itself may cause adverse effects. Therefore, researchers have been prompted to prepare viable replacements for the attenuated vaccines that would be more effective and safer to use. DNA vaccines are generally composed of a double stranded plasmid that includes a gene encoding the target antigen under the transcriptional directory and control of a promoter region which is active in cells. Plasmid DNA (pDNA) vaccines allow the foreign genes to be expressed transiently in cells, mimicking intracellular pathogenic infection and inducing both humoral and cellular immune responses. Currently, because of their highly evolved and specialized components, viral systems are the most effective means for DNA delivery, and they achieve high efficiencies (generally >90%), for both DNA delivery and expression. As yet, viral-mediated deliveries have several limitations, including toxicity, limited DNA carrying capacity, restricted target to specific cell types, production and packing problems, and high cost. Thus, nonviral systems, particularly a synthetic DNA delivery system, are highly desirable in both research and clinical applications.