Pancreatic cancer (PDAC) affects 4400 Canadians each year and with 5year survival rates <8%, there is clearly an unmet need for new therapeutic approaches for treating this deadly disease. Herein I report the development of a surgical model of PDAC that recapitulates many of the hallmarks of human disease and has an immune infiltrate consisting of T cells and suppressive regulatory T cells and myeloid derived suppressor cells. This model allows the exploration of new therapeutics that can be used in combination with surgical resection of primary tumours. Furthermore, I propose that the use of neoadjuvant administration of a prime-boost oncolytic vaccine targeting a pancreatic tumour associated antigen (TAA) - mesothelin - could potentiate pancreatic tumour specific immune responses to improve patient prognosis. We demonstrate that immune tolerance to this self antigen can be broken by the complete depletion of circulating Tregs at the time of vaccination, which leads to the activation of a population of CD8+ T cells responsive to mesothelin. We demonstrate that these T cells respond to mesothelin expressing tumour cells ex vivo, and that CD8+ T cells are recruited to the site of tumour challenge. However, despite the generated CD8+ T cell response, oncolytic vaccine strategies targeting mesothelin provide no protection against Pan02 tumours, or against other mesothelin expressing murine tumour lines. I demonstrate that this is not through common tumour escape mechanisms, nor through the upregulation of suppressive immune populations. Any efficacy observed was found to be provided solely by depletion of Tregs, as the depletion of CD8+ T cells did not reduce protection from tumour outgrowth in vaccinated mice. While mesothelin represents a promising target, it is not an ideal target for oncolytic vaccine platforms, potentially due to its nature as a self antigen.

Indiana University-Purdue University Indianapolis (IUPUI) / During the last two years, women of reproductive age (WRA) have experienced uncertainty about the COVID-19 vaccine, particularly as it relates to reproductive health (e.g., fertility) due to the COVID-19 infodemic. Because WRA are a pivotal population in pandemic control, it is important to understand how WRA manage vaccine-related uncertainty. Uncertainty management theory (UMT) considers the complexities of uncertainty, acknowledging that individual appraisals of, and responses to, uncertainty may vary from person to person and evolve over time. This study examined factors contributing to WRA’s hesitancy to receive the COVID-19 vaccine, including uncertainty about potential side effects, concern about safety and efficacy, and conflicting information. WRA most frequently felt neutral towards their uncertainty; however, negative emotional responses to uncertainty played an influential role in many WRA’s responses to uncertainty (e.g., avoiding information, seeking information, receiving the COVID-19 vaccine). The findings of this study provided insight on how WRA have experienced uncertainty about the COVID-19 vaccine, including their emotional responses to and subsequent appraisals of their uncertainty which ultimately influenced their responses.

Background: Pertussis diagnosis may go unrecognized when other pathogens, such as respiratory syncytial virus (RSV) circulate. Methods: A prospective cross-sectional study was conducted in Lima, Peru from January 2009 to September 2010. A total of 596 children under 5 years old admitted with clinical diagnoses of acute respiratory infections were test for B. pertussis and RSV detection by polymerase chain reaction (PCR). Results: The pertussis toxin and IS481 genes were detected in 19.12% (114/596) of the cases and the respiratory syncytial viruses (RSV-A and RSV-B) were identified in 17.28% (103/596) of patients. Infants under 3 months old were the most frequently affected by this pathogens in 43% (49/114) and 35.9% (37/103) respectively. An increase of B. pertussis was observed from February to March and from October to November with a Seasonal index between 1.32-1.51 and 1.24-3.5 respectively. Conclusions: Epidemiologic surveillance for B. pertussis is essential in Peru, especially in children that could most benefit from the vaccine. B. pertussis should be suspected in infants hospitalized for acute respiratory symptoms for early treatment and prevent complications. / Tesis

Individuals who work with children are at risk for exposure to vaccine-preventable diseases. School settings can quickly become outbreak centers for communicable infection since school employees are in direct contact with children in confined areas for many hours each day. Therefore, it is important for school employees to be fully vaccinated. There are many reasons school employees may be inadequately vaccinated. One common myth is that adults believe vaccines are only for children. Another reason for inadequate vaccination rates among school employees is that many adults believe vaccinations received during childhood are still effective. Healthcare providers (HCPs) constitute the first line of defense to ensure adults are adequately vaccinated and, when vaccinations are tracked and recommended by HCPs, vaccination uptake is improved among patients. Unfortunately, many HCPs miss opportunities to vaccinate their adult patients. By discussing recommended vaccinations with adult patients, Nurse Practitioners can be instrumental in improving vaccination rates among school employees.

Bovine mastitis is a significant disease affecting the dairy industry worldwide. The most frequently causative agent of contagious bovine mastitis is Staphylococcus aureus that produces numerous virulence factors contributing to its pathogenesis. However, it is not clearly defined which virulence factors play a critical role in bovine mastitis due to the heterogeneous virulence factor profiles in S. aureus isolated from different hosts and disease types. Among many virulence factors, it has long been postulated that staphylococcal cytotoxins and superantigens (SAgs) play an important role in the pathogenesis of S. aureus in bovine mastitis due to their potent toxicity toward host immune response. However, it has been a great challenge to determine the definite role of staphylococcal cytotoxins and SAgs in S. aureus pathogenesis due to the presence of multiple redundant cytotoxins and SAgs in a single S. aureus strain. Our longterm goal is to develop an effective vaccine to protect dairy cattle from S. aureus infection. The objective of this study is to; 1) determine the role of staphylococcal cytotoxins and superantigens in bovine mastitis; 2) develop a inducible and secretory expression vector and host system for a high production yield of recombinant protein; and 3) evaluate the protective effect of recombinant protein vaccine composed of staphylococcal cytotoxins and SAgs. The rationale of the proposed research is that development of an effective vaccine against S. aureus will prevent significant economic loss in the dairy industry and reduce the use of antibiotics in the dairy industry to prevent emergence of antibiotic resistance pathogens

No description available.

No description available.

Chlamydia is the most prevalent sexually transmitted bacterial infection in many developed countries, including Canada. Untreated infections in women can lead to a number of complications including pelvic inflammatory disease, tubal factor infertility, and ectopic pregnancy. Public health programs, including screening for at-risk individuals, partner identification, and antibiotic treatment, have had limited success in controlling the rising incidence of chlamydial infections over the past two decades. A chlamydia vaccine that prevents infection and its pathological sequelae is the next essential step to control this persistent public health problem. Chlamydia spp. utilize the highly conserved type III secretion (T3S) system as an essential virulence factor for infection and intracellular replication. Here, we evaluated a novel chimeric antigen (BD584) consisting of three T3S proteins from C. trachomatis (CopB, CopD, and CT584) as a potential chlamydia vaccine candidate. Intranasal immunization with BD584 elicited strong humoral responses that neutralized infection in vitro. Following intravaginal challenge with C. muridarum, immunized mice had a 95% reduction in chlamydial shedding and a 87.5% reduction in incidence of upper genital tract pathology compared to control mice. BD584 immunization generated strong cell-mediated and mucosal antibody responses in mice with different genetic backgrounds, and conferred protection against an intravaginal C. trachomatis infection in two out of three strains of mice. BD584 formulated with NE01, a mucosal adjuvant known to be safe and effective in humans, was shown to be highly immunogenic and efficacious against C. trachomatis infection in mice. These results suggest that BD584 may represent a promising antigen for use in a chlamydia vaccine. / Thesis / Doctor of Philosophy (PhD) / Chlamydia is the most common sexually transmitted bacterial infection in the world. The goal of this thesis is to evaluate a novel chlamydia vaccine in a mouse model of genital chlamydia infection. We engineered a fusion protein, BD584, made up of three highly conserved type III secretion (T3S) proteins CopB, CopD, and CT584. We show that vaccination with BD584 generated strong immune responses and protected mice from chlamydia infection and the associated reproductive tract disease. Interestingly, the level of protection afforded by BD584 vaccination is dependent upon the genetic background of the animal. Furthermore, we have identified particular antibody subtypes directed against BD584 as markers of BD584-mediated protective immunity. Lastly, we show that vaccination with BD584 formulated with a clinically safe and effective mucosal adjuvant generates robust immune responses and confers protection against chlamydia in mice. Together, these results provide support for the use of T3S proteins in a chlamydia vaccine.

Bacillus anthracis is a facultative extracellular bacterial pathogen that causes cutaneous, gastrointestinal or respiratory disease in many vertebrates, including humans. Commercially available anthrax vaccines for immunization of humans are known to provide protection of limited duration and may not protect against the respiratory form of the disease. Commercially available live vaccines for animals have been shown to cause disease in certain species. Brucella abortus is a facultative intracellular bacterium that causes chronic infection in animals and humans. As with other intracellular pathogens, cell mediated immune responses (CMI) are crucial in affording protection against brucellosis. B. abortus strain RB51 has been shown to be useful in eliciting protective CMI and antibody responses against Brucella in cattle and other animal species. Since the protective antigen (PA) of B. anthracis is known to induce antibodies, the pag gene encoding PA was expressed in B. abortus RB51, producing a dual vaccine to protect against both brucellosis and anthrax. In a previous study, the entire pag gene was expressed in strain RB51 and following immunization the vaccine induced antibodies against PA in A/J mice. However, PA stability and protective efficacy were less than desirable as only 1/6 were protected. The studies in this dissertation involved synthesizing a gene corresponding to domain 4 (PA4) of the pag gene utilizing the native codon usage of Brucella. The PA4 domain was fused to Brucella signal sequences of Brucella 18kDa protein, superoxide dismutase or no signal sequence to localize the PA4 to the outside cell envelope, periplasmic space or cytosol respectively. Comparisons of the expression level and stability of the native and synthetic PA4 in B. abortus strain RB51 were assessed by immunoblot. The protective efficacy of PA4 expressed in Brucella was assessed by immunization and protection studies in A/J mice against a live challenge with either B. abortus or B. anthracis Sterne spores. ELISA and western blot indicate the induction of PA specific antibodies by these recombinant strain RB51 vaccine constructs. Results based on subisotype antibody ELISA (IgG, IgG1, IgG2a and IgM) and CMI assays (cytokine ELISA of IL-4 and INF-g, and LPA) suggest a Th1 based immune response to strain RB51 and PA. B. abortus strain RB51 expressing PA4 fused to the signal sequence of Brucella 18kDa protein was able to induce 50% protection, while strain RB51 expressing PA4 with no signal sequence gave 17% protection against B. anthracis Stern spore challenge. Mice were boosted with an intraperitoneal injection of purified PA after an initial immunization with Brucella vaccine candidates, sterile saline or pure PA. Protection assessed by live challenge with B. anthracis Sterne spores increased following boosting with PA in 4 cases. Immunization with purified PA, and 3 strain RB51/PA vaccines and a PA boost gave protection against a spore challenge ranging from partial to full. This study suggests that additional work is needed to define the antigens of B. anthracis involved in the induction of specific CMI. / Ph. D.

Bacillus anthracis is a facultative intracellular bacterial pathogen that can cause cutaneous, gastrointestinal or respiratory disease in many vertebrates, including humans. Commercially available anthrax vaccines for immunization of humans are of limited duration and do not protect against the respiratory form of the disease. Brucella abortus is a facultative intracellular bacterium that causes chronic infection in animals and humans. As with other intracellular pathogens, cell mediated immune responses (CMI) are crucial in affording protection against brucellosis. B. abortus strain RB51 has been shown to be useful in eliciting protective cell mediated immunity and humoral responses against Brucella in cattle and other animal species. Since the protective antigen (PA) of B. anthracis is known to induce protective antibodies, it was decided that the objective of this research was to test whether the gene encoding PA could be expressed in Brucella producing a bivalent vaccine to protect against both brucellosis and anthrax. The pag gene was transcriptionally fused to promoters of genes encoding superoxide dismutase or heat shock protein groE, subcloned into a broad host range plasmid (pBBR1MCS) and shown to express in E. coli by immunoblotting using antiserum specific for PA. The immunoblot results revealed that E. coli produced a PA protein of the expected size. In addition, the culture medium was shown to contain the same PA protein using immunoblotting. These results show that E. coli is capable of expressing B. anthracis PA in both the cellular and extracellular forms. The pBB/PA plasmid was used to transform B. abortus RB51 and CmR clones screened for the expression of PA by immunoblotting. Twenty clones of strain RB51/pBBSOD were show to express a 30kDa PA protein. Three clones of strain RB51/pBBGroE-PA were shown to express a 63-83kDa protein as detected by antiserum specific for PA. Using the A/J mouse, an immunocompromised vertebrate model, immunization and challenge studies were performed. Preliminary results demonstrate that the bivalent vaccine is capable of producing protection against a live challenge with B. abortus and some protection against live non-disease producing spores of B. anthracis. / Master of Science