No description available.

Pacific salmon migrate long distances to spawn as part of their life cycle. During this journey from sea to their natal stream, they undergo major endocrine, physiological and immune changes. Cortisol, the primary stress hormone, gradually increases during the journey. Persistent high cortisol levels have deleterious health effects, including suppression of the antibody response. However, pathogens encountered during their journey may stimulate antibody responses to overcome the infection. My main research question focuses on how salmonids balance the immunosuppressive effects of high cortisol levels with activation of the antibody response. A recent field study from our lab showed a transient increase in abundance of B cells during the spawning run which is suggestive of activation of the immune system during this journey. However, our field study had too many confounding variables. In this study, we investigated the activation of the antibody response under conditions of elevated levels of cortisol in rainbow trout under laboratory-controlled conditions. We looked at the effects of a) cortisol alone, b) fish pathogen Flavobacterium psycrophilum (Fp) alone and c) combined cortisol and Fp challenge on the gene expression of immunoglobulins IgM and IgT using qPCR. We have found that cortisol suppresses the IgM response in the spleens of Fp-susceptible line but not in Fp-resistant line of Rainbow trout. No significant effects on B cell development where observed in the anterior kidney. Taken together, our data suggest that the antibody response in Fp-resistant rainbow trout is less sensitive to increased cortisol levels compared to Fp-susceptible fish, confirming our hypothesis that Fp-resistant fish have in some way evolved to manage stress more successfully.

Human immunodeficiency virus (HIV) infects and destroys lymphocytes, leading to acquired immunodeficiency syndrome. Homosexual men were impacted disproportionately in the early years of the pandemic, while women are now the majority of those infected, making development of anti-HIV treatments and preventatives effective in the female reproductive tract (FRT) imperative. Here, we investigated HIV prevention in women through 1) discovery of antivirals effective in the FRT; and 2) determining a mechanism by which bacterial vaginosis (BV), a disorder of the FRT in which protective Lactobacillus are replaced by BV-associated bacteria (BVAB), increases HIV transmission. We identified a small molecule active against HIV from an extensive compound library and used its structure for an in silico screening, identifying a novel class of HIV inhibitors, Avirulins. Three were active in the low micromolar range and exhibited HIV-1 reverse transcriptase inhibition. Avirulins were not cytotoxic to FRT epithelial cells and maintained activity in human cervicovaginal fluid (CVF). With continued development, Avirulins could serve as additions to antiretroviral therapies or preventatives for the FRT. Next, we hypothesized that BV increases HIV transmission though disruption of the FRT epithelium at the endocervical monolayer, as most FRT lymphocytes reside below the epithelium. We determined that matrix metalloproteinases (MMPs) were secreted by endocervical epithelium in response to BVAB and could depolarize endocervical cell layers. When HIV infected lymphocytes were cocultured with endocervical cell layers, treatment with conditioned media from endocervical cells cocultured with BVAB increased HIV transmigration. Treatment with MMP inhibitors reduced this effect. We demonstrated that CVF from women with BV had greater MMP activity, and presence of certain MMP isotypes in CVF correlated with increased HIV transmigration through the endocervical epithelium. These results propose endocervical disruption by MMPs as a mechanism for BV-induced HIV transmission and suggest the potential of MMP inhibitors as HIV preventatives.

No description available.

Mycobacterium tuberculosis (M.tb) is the causative agent of pulmonary tuberculosis (TB). Over 25% of the world’s population is estimated to be infected with tuberculosis, yielding over 10 million new cases and over 1.5 million deaths in 2017 alone. This is all despite the near universal implementation of bacille Calmette-Guérin (BCG) vaccination across TB endemic areas. BCG is capable of preventing childhood disseminated forms of disease but fails to induce potent immunity within the lung. We expect this to in part play a role in the lack of protection against pulmonary TB. Our lab has developed a human adenovirus serotype 5 vaccine expressing the M.tb antigen Ag85A (AdHu5Ag85A). When delivered directly to the respiratory mucosa (RM), AdHu5Ag85A has proven to be safe and immunogenic, generating both CD4 and CD8 T cell responses within the lung. We have found that RM AdHu5Ag85A vaccination also generates a long-lasting population of memory macrophages in the airway and lung, that are primed to better control early M.tb infection. Importantly, this was a vaccination route-dependent mechanism. Memory macrophages express a trained innate immune phenotype as they express high levels of MHC II, are highly glycolytic, and produce more IL-12 upon re-stimulation. Importantly, utilization of an in vivo T cell depletion approach allowed us to show that these memory macrophages are capable of limiting early M.tb infection independent of T cells. Our findings indicate that RM vaccination may be advantageous to parenteral routes by not only drawing antigen specific T cells into immunologically restricted lung mucosa but also generating a memory macrophage population within the lung. Induction of memory macrophages within the airway helps overcome early innate immune suppression by M.tb. / Thesis / Master of Health Sciences (MSc) / Tuberculosis (TB) is a pulmonary disease responsible for 10 million new clinical cases and more than 1 million deaths annually. Over one quarter of the world is believed to be infected with TB. This is despite the near-universal administration of bacille Calmette-Guérin, a preventative TB vaccine, and an effective, but lengthy antibiotic treatment. With antibiotic resistance on the rise, developing a protective vaccine against TB is more important than ever. Tuberculosis has confounded researchers for decades and has thus escaped development of a more effective vaccine. One of the ways to improve a TB vaccine would be to inhale it, to have local effects at the main site of TB infection in the lung. We found that by aerosolizing our vaccine, we can impact local immunity within the lung in a way that has never before been described, opening new avenues for TB research.

One strain of Bacillus subtilis and three antibiotic-resistant strains of Staphylococcus aureus were employed to determine the biological effects of everninomicin B (EvB), a naturally occurring antibiotic produced by Micromonospora carbonacea (NRRL 2972) and M. carbonacea var. aurantiaca. Minimum inhibitory concentration (MIC) of EvB for B. subtilis was 1.2 x 10-3 µmole/ml of EvB in glucose minimal broth and 2.6 x 10-3 µmole/ml of EvB in nutrient broth. MIC values of EvB for S. aureus were 3.25 x 10-4 µmole/ml of EvB for strains resistant to penicillin or tetracycline and 6.5 x 10-4 µmole/ml of EvB for the aminoglycoside-resistant strain. The inhibitory effect of EvB was found to be reversible for all concentrations of EvB and all bacterial strains tested. The inhibitory effect of EvB for B. subtilis was not dependent upon the initial concentration of cells nor the stage in the growth cycle at the time the compound was introduced. The inhibitory effect was dependent upon the initial concentration of cells for S. aureus. Electron microscopy studies showed distinct morphological changes in treated cells of S. aureus. Cellular lysis in these cells was also detected.

The drug of choice for the treatment of Stieptococcal pharyngitis is penicillin G. However, a common home remedy prescribes the use of salt-water solutions for gargling. Members of Beta -hemolytic streptococcal groups A, B, and C were isolated from the upper -respiratory tracts of patients diagnosed as having streptococcal pharyngitis. These cultures we:e obtained from HCA Greenview Hospital (Bowling Green, Kentucky) and used to study the effects of sodium chloride on the isolates. The minimum inhibitory concentration of sodium chloride was determined for each of eight hospital isolates. Croup A streptococci were inhibited at a concentration of 7.2% sodium chloride while Group C streptococci were inhibited at a 7.0% concentration. Group P streptococci were more resistant, and inhibition of growth occurred at 12.0% sodium chloride concentrations. Scanning electron microscopic studies showed no significant differences in the external structure of cells treated with sodium chloride when compared to non-treated cells. Despite the lack of changes in the external structure of treated cells, fine structural alterations were observed with transmission electron microscopic studies. Treatment of the cells with sodium chloride resulted in a condensation of nucleoid deoxyribonucleic acid (DNA) and some loss of ribosomes. These changes were followed by a dissolution of the cytoplasmic cell contents resulting in an intact cell wall with capsule. Other parameters such as the rate of growth, minimum bactericidal concentrations, DNA content and protein content of cells treated with sodium chloride were examined and compared to control cells.

Dissertation (Ph.D.)--Auburn University, 2006. / Abstract. Vita. Includes bibliographic references.

Presentation: A 3 month-old male is referred for admission with a 2-day history of fever, having been diagnosed with pneumonia and prescribed a cephalosporin on the previous day. A blood culture obtained at that time is positive for coagulase negative Staphyloccocus. On exam, he is ill-appearing. He has bilateral conjunctivitis that spares the limbus, non-exudative pharyngitis, and a polymorphic truncal rash. There is no appreciable cervical lymphadenopathy or extremity involvement. A chest x-ray demonstrates a round infiltrate of the left upper lobe, and initial labs reveal a white blood count of 17.5, a C-reactive protein (CRP) of 23.9 mg/dL, and a normal comprehensive metabolic panel. His positive blood culture is deemed a contaminant, and antibiotic coverage for community-acquired pneumonia is given with ampicillin. Diagnostic evaluation: On day 5 of illness, his fevers persist despite broadened antibiotic coverage. Further work-up has ruled out viral respiratory pathogens and Epstein-Barr virus as a cause of persistent fevers. Incomplete Kawasaki disease is suspected due to continued fevers, the presence of three clinical criteria, and further increase in his CRP. He lacks other supplemental laboratory criteria, so an echocardiogram is obtained that shows mild dilation of the left anterior descending artery (LAD) of indeterminate significance. A repeat echocardiogram 2 days later reveals progressive dilation of left main coronary artery (LMCA), LAD, and right coronary artery (RCA). Diagnosis: Dilation of the LAD and RCA confirm a diagnosis of incomplete Kawasaki disease. Within 48 hours of treatment with IVIG and high-dose aspirin, the patient is afebrile with resolving symptoms and a declining CRP. He is discharged on the 9th day of illness on low dose aspirin and a cephalosporin to complete an antibiotic course for concurrent pneumonia. Conclusion & Discussion: This case illustrates the importance of maintaining a high index of suspicion for an incomplete presentation of Kawasaki disease, particularly among infants. The American Heart Association’s guidelines were updated in 2017 to improve recognition of incomplete Kawasaki disease, particularly among infants who are more likely to have an incomplete presentation, abnormalities of the coronary arteries, and a delayed diagnosis. The key to this patient’s diagnosis was the presence of a bilateral conjunctivitis that spared the limbus. A bilateral, non-exudative conjunctivitis that spares the limbus has been recognized as a feature suggestive of Kawasaki disease for the better part of four decades; our review of the literature suggests this feature is highly specific to the diagnosis of Kawasaki disease.

Emerging infectious diseases (EID) pose a serious threat to global public health. Computational epidemiology is a nascent subfield of public health that can provide insight into an outbreak in advance of traditional methodologies. Research in this dissertation will use fuse nontraditional, publicly available data sources with more traditional epidemiological data to build and parameterize models of emerging infectious diseases. These methods will be applied to avian influenza A (H7N9), Middle Eastern Respiratory Syndrome Coronavirus (MERS-CoV), and Ebola virus disease (EVD) outbreaks. This effort will provide quantitative, evidenced-based guidance for policymakers and public health responders to augment public health operations. / Ph. D.