HIV and Tuberculosis (TB) co-infection place an immense burden on health care systems as they act in synergy to worsen disease prognoses. TB is the most common cause of death in people living with HIV (PLWH) and in turn, HIV is the most significant risk factor for progressing from latent to active TB disease. While HIV and TB are endemic in sub-Saharan Africa, they also disproportionately affect marginalized populations in Canada. Unfortunately, the only licensed TB vaccine, BCG, does not protect from adult pulmonary TB and is not recommended for PLWH. Thus, the development of novel TB vaccines, which are safe and effective in PLWH, remains an urgent global necessity. We have found that humanized mice (hu-mice) are ideal models to research this as they can be successfully infected with HIV, TB and HIV/TB and recapitulate human disease pathology. A next-generation respiratory mucosal (RM) trivalent chimpanzee adenoviral-vectored vaccine (Tri:ChAd68) was developed and tested in our naïve and HIV-infected hu-mice. When immunizing naïve hu-mice, a trend of increased M.tb-specific CD4+ T cells producing IFNγ and TNFα in the lungs and spleen was observed. After subsequent M.tb infection, the vaccinated naïve hu-mice also exhibited significantly reduced lung mycobacterial burden, tissue dissemination and lung pathology. We then investigated the vaccine immunogenicity and ability to protect from TB in the context of HIV. Our immunized HIV-infected hu-mice were also able to produce M.tb-specific T cells and when challenged with M.tb, we observed a decreased trend in mycobacterial load in the lungs, indicating that the vaccine may be able to offer protection against TB when a prior HIV infection is present. These findings demonstrate the protective potential of the RM Tri:ChAd68 vaccine against TB disease for PLWH. In the future, we will test this vaccine in antiretroviral treated HIV-infected hu-mice to increase clinical significance. / Thesis / Master of Science in Medical Sciences (MSMS) / HIV and TB are major diseases that can occur together, severely worsening patients’ health and challenging global healthcare systems. The current TB vaccine, BCG, isn’t ideal for people living with HIV (PLWH), causing this vulnerable population to be at greater risk of getting TB infection. Therefore, developing a new TB vaccine that is safe and effective in PLWH is an urgent global issue. We used humanized mice that develop human immune cells to test a novel TB vaccine delivered to the lungs (Tri:ChAd68) to see if it could protect against TB and overcome immune challenges from HIV. We saw increased immune responses and lower TB infection in our vaccinated humanized mice and the vaccine appeared to also be beneficial in the mice that had prior HIV infection. This suggests the Tri:ChAd68 vaccine may be able to offer protection against TB in PLWH; however, more studies are needed to conclude this.

In the last decade, the potential of β-glucan, a fungal cell wall component, to induce epigenetic and functional modification of innate immune cells, signified as trained innate immunity (TII) has been demonstrated in several pre-clinical and clinical studies. Parenteral administration of β-glucan has resulted in centrally induced TII in the bone marrow/circulating monocytes. Such trained innate immune cells play a critical role in protection against secondary infections. However, there are now indications that inducing local long-lasting immunity at mucosal barrier tissues such as the lung is warranted for protective immunity against respiratory pathogens. Currently, it remains unclear whether respiratory mucosal administration of β-glucan will induce long-lasting resident-memory macrophages and TII and if so, what are the underlying mechanisms of development and maintenance of memory macrophages at respiratory mucosa. To address this, and kinetics of immune responses in the lung were studied. Profound changes in airway macrophage (AM) pools were observed starting from 3 days post-exposure, which was associated with monocyte recruitment, and this was followed by a series of phenotypic shifts in AMs. The altered AM phenotype profile persisted for up to 8 weeks post-exposure. Importantly, β-glucan-trained AMs demonstrated heightened MHC II expression, enhanced responses to secondary stimulation and improved capacity to perform bacterial phagocytosis. Furthermore, mice with, β-glucan-trained AMs displayed higher rates of survival and improved bacterial control, in the lung and periphery, following a lethal S. pneumoniae infection. Our findings together indicate that a single intranasal delivery of β-glucan is able to train AMs. Further work into epigenetics, metabolism, and the contribution of AMs in protection is needed. / Thesis / Master of Health Sciences (MSc) / The immune system has been classically divided into two major compartments known as the innate and adaptive immune system. For decades, the predominant consensus amongst the field was that only the adaptive immune system can form memory against any pathogens encountered. It has been well established that plants and invertebrates only possess an innate immune system and still show boosted responses and enhanced protection against previously encountered as well as new pathogens. Recently, such capacity for innate immune memory has also been demonstrated in humans and pre-clinical animal models. Innate immune memory provides non-specific, broad- spectrum protection whereas adaptive memory is specific to a singular pathogen. Inducing broad-spectrum protection can be crucial for the future of human medicine. Activation of both adaptive and innate immune arms could prove to be extremely beneficial in vaccination strategies. Through the use of a pre-clinical model, we have found that administering β-glucan, a component of fungal cell wall, directly into the lung significantly alters the phenotype and functionality of lung immune cells, and also provides enhanced protection against a heterologous infection.

The diagnostic accuracy attained with the use of transbronchial fine needle aspiration biopsy, aspiration of bronchial secretion, bronchial washing, brush biopsy and forceps biopsy via a flexible fiberoptic bronchoscope was compared in patients with carcinoma of the lung. In endoscopic visible tumours the sensitivity of forceps biopsy was higher than that of the other methods. When forceps biopsy was combined with bronchial washing the overall diagnostic accuracy was significantly higher than that of any of the single methods, while no appreciable increase was obtained by adding additional methods. Selective brush biopsy from every segment bronchus has been established as a method in the search for occult bronchial carcinoma. The extent of respiratory mucosal damage and wound healing after brush biopsy was therefore studied in rabbits. Large differences in the extension and depth of the damage was observed. The basement membrane was often penetrated. Regeneration started during the first day after brush biopsy and a normal ciliated epithelium was restored within three weeks. To determine if the bronchoscope itself damaged the respiratory epithelium, bronchial mucosa was studied in the pig after examination with a flexible fiberoptic bronchoscope. The columnar epithelial cells were torn off in areas where the bronchoscope had rubbed against the airway wall but the basement membrane was not damaged. Since the function of the respiratory epithelium is to remove inhaled particles from the airways, mucociliary clearance was studied in man after fiberoptic bronchoscopy. The study suggests that the tracheobronchial clearance system has a large reserve for mechanical trauma. Mucociliary clearance can however be decreased after fiberoptic bronchoscopy in some patients. An increasing number of patients with impaired cardiopulmonary function are today subjected to examination with flexible fiberoptic broncoscopy. The haemodynamic effects of fiberoptic bronchoscopy performed under topical anaesthesia were therefore studied in patients with restrictive lung disease. The procedure induced marked haemodynamic changes during passage of the larynx and during suctioning. A slight fall in arterial oxygen tension was observed during bronchial suctioning and in the post-bronchoscopic period. Three of ten patients developed ST-T-segment changes during bronchial suctioning. / <p>S. 1-48: sammanfattning, s. 49-126: 5 uppsatser</p> / digitalisering@umu.se

In the recent years, it has been well established that primary respiratory viral infection-induced lung resident memory CD8 T cells (TRM) characterized by the expression of integrins CD49a and CD103, as well as the early-activation marker CD69, constitute the first line of defense against reinfection. On the other hand, viral vector-based respiratory mucosal (RM) vaccination, as well as parenteral vaccination followed by airway luminal manipulation induce lasting and protective lung T cell immunity towards pulmonary tuberculosis (TB). However, it remains poorly understood whether and how these TB vaccination strategies induce TRM in the lung. As such, within this thesis we will investigate generation of lung CD8 TRM upon different TB vaccination strategies and the underlying mechanisms regulating establishment of such cells. Here using distinct models of replication-deficient adenoviral vector-based TB vaccination, we find that RM vaccination leads to generation of lung CD8 TRM identified by the expression of CD69, CD103, and very late activation Ag 1 (VLA-1). These TRM-associated molecules are acquired by CD8 T cells in distinct tissues. In this regard, VLA-1 is acquired during T cell priming in draining mediastinal lymph nodes (dMLNs) and the others acquired after T cells entered the lung. Once in the lung, Ag-specific CD8 TRM continue to express VLA-1 at high levels through the effector/expansion, contraction, and memory phases of T cell responses. We also reveal that VLA-1 is not required for homing of these cells to the lung, but it negatively regulates them in the contraction phase. Furthermore, VLA-1 has a negligible role in the maintenance of such cells in the lung. Separately, we have observed that while parenteral intramuscular vaccination alone does not induce lung CD8 TRM, subsequent RM inoculation of an Ag-dependent, but not a non-specific inflammatory agonist induces lung CD8 TRM. Such generation of lung CD8 TRM needs CD4 T cell help. These findings not only fill the current knowledge gap, but also hold important implications in developing effective vaccination strategies towards mucosal intracellular infectious diseases such as acquired immunodeficiency syndrome (AIDS), TB and herpes virus infection. / Thesis / Doctor of Philosophy (PhD)