The aim of the present study was to determine how lymphokines could exert their biological action on the skin during the course of the delayed hypersensitivity reactions. Four groups of experiments were conducted to investigate: (1) The production and the separation of lymphokines, (2) the protease activity of lymphokines and the effect of lymphokines on the kinin-forming system, (3) the effect of lymphokines on mast cells and platelets, and (4) the effect of enzyme-treated lymphokines on the skin inflammatory reaction. Guinea pig lymph node lymphocytes, stimulated by either the specific antigen DNP-BGG or by concanavalin A, were used to generate lymphokines. Parameters for testing lymphokine activities were those of migration inhibitory factor (MIF) and skin reactive factor (SRF). Separation of MIF and SRF from the lymphokine preparation by gel filtration, electrophoresis and fractional precipitation with ammonium sulphate was unsuccessful, which indicated that the physical properties of MIF and SRF were similar. Lymphokine preparations contained little or no neutral and acidic protease activities. / Medicine, Faculty of / Pathology and Laboratory Medicine, Department of / Graduate

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Viral diseases constitute a major threat to the agricultural production and food security throughout the world. Plants cope with the invading viruses by triggering immune responses and small RNA interference (RNAi) systems. In prokaryotes, CRISPR/Cas systems function as an adaptive immune system to provide bacteria with resistance against invading phages and conjugative plasmids. Interestingly, CRISPR/Cas9 system was shown to interfere with eukaryotic DNA viruses and confer resistance against plant DNA viruses. The majority of the plant viruses have RNA genomes. The aim of this study is to test the ability of the newly discovered CRISPR/Cas13a immune system, that targets and cleaves single stranded RNA (ssRNA) in prokaryotes, to provide resistance against RNA viruses in plants. Here, I employ the CRISPR/Cas13a system for molecular interference against Turnip Mosaic Virus (TuMV), a plant RNA virus. The results of this study established the CRISPR/Cas13a as a molecular interference machinery against RNA viruses in plants. Specifically, my data show that the CRISPR/Cas13a machinery is able to interfere with and degrade the TuMV (TuMV-GFP) RNA genome. In conclusion, these data indicate that the CRISPR/Cas13 systems can be employed for engineering interference and durable resistance against RNA viruses in diverse plant species.

During the course of HIV pathogenesis, the virus induces multiple defects in immune cells, altering their functional ability to efficiently control HIV itself and other infections. Whilst the widespread implementation of antiretroviral therapy (ART) has led to reduced morbidity and mortality in most HIV-infected individuals having access to treatment, we still do not know whether full restoration of immune function occurs. The aim of this study was to assess the extent to which ART restores both phenotypic and functional T and B cell immunity. HIV-infected women were studied before and 1 year after ART initiation. In Chapter 2, the effect of ART on T cell activation and differentiation profiles was evaluated in HIV-infected individuals (n=28; pre- and post-ART), and compared to HIVuninfected age- and sex-matched controls (n=23). In Chapter 3, the restoration of copathogen specific CD4+ T cells was determined by comparing their cytokine secretion ability and memory differentiation profiles in response to Mycobacterium tuberculosis and cytomegalovirus in HIV-infected (n=15; pre- and post-ART), compared to uninfected (n=9) individuals. Finally, Chapter 4 examined changes in B cell activation and memory profiles in HIV-infected persons (n=19; pre- and post- ART), and compared profiles to HIV-uninfected individuals (n=19). Multiparameter flow cytometry was performed to address the study objectives. T cell activation, as measured by CD38 and HLA-DR expression, was significantly reduced one year after ART for both CD4+ and CD8+ T cells, but normalisation to levels in HIV-uninfected individuals did not occur, despite suppression of viral load. In addition, skewed CD4+ and CD8+ T cell memory profiles were not completely restored. Furthermore, no change in the cytokine production capacity and memory profile of pathogen-specific CD4+ T cells was found before and after ART, but pathogen-specific CD4+ T cells exhibiting a late differentiated profile (CD27- CD45RO+) had a lower ability to replenish (p=0.02; r = -0.5) compared to cells with an early differentiated profile (CD27+CD45RO+; p=0.04; r = 0.45) prior to ART. Similar to T cells, activated B cells (CD40+CD86+) were only partially normalised post-ART, and remained significantly higher than B cells of HIV-uninfected individuals. The frequency of all B cell memory subsets were comparable between HIV-treated and uninfected individuals, with the exception of plasmablasts, whose frequency was still significantly higher than in HIV-uninfected subjects. In summary, these results demonstrate that HIV-infected women on suppressive ART show a substantial but only partial normalisation of T cell and B cell memory subsets, and lower levels of T cell and B cell activation. In addition, restoration of co-pathogen specific memory CD4+ T cells upon treatment was dependent on their memory profile before ART. Understanding the impact of HIV on T and B cell dysfunction and restoration upon ART may provide important insights into the mechanisms of HIV pathogenesis in the era of ART.

The cells and molecules that comprise the immune system are essential for mounting an effective response against microbes. A successful immune response limits pathology within the host while simultaneously eliminating the pathogen. The key to this delicate balance is the correct recognition of the pathogen and the appropriate response of immune cells. Cellular activation originates through receptors that relay information about the state of the microenvironment to different compartments within the cell. The rapid relay of information is called signal transduction and employs a network of signaling mediators such as kinases, phosphatases, adaptor molecules, and transcription factors. IL-2 inducible T cell kinase (Itk) is a non-receptor tyrosine kinase that is an integral component of signal transduction downstream of many immunoreceptors. This dissertation describes two distinct pathways that utilize Itk in both phases of the immune response. T cells use the TCR to sense a multitude of peptide-based ligands and to transmit signals inside the cell to activate cellular function. In this regard, the diversity of ligands the T cells encounter can be portrayed as analog inputs. Once a critical threshold is met, signaling events transpire in close proximity to the plasma membrane to activate major downstream pathways in the cell. The majority of these pathways are digital in nature resulting in the on or off activation of T cells. We find, however, that altering the TCR signal strength that a T cell receives can result in an analog-based response. Here, the graded expression of a transcription factor, IRF4, is modulated through the activity of Itk. We link this graded response to an NFAT-mediated pathway in which the digital vs. analog nature has been previously uncharacterized. Finally, we demonstrate that the repercussions of an analog signaling pathway is the altered expression of a second transcription factor, Eomes, which is important in the differentiation and function of T cells. These results suggest that Itk is crucial in the modulation of TCR signal strength. Mast cells primarily rely on the IgE-bound FcεR1 for pathogen recognition. Crosslinking this receptor activates mast cells and results in degranulation and cytokine production via an expansive signaling cascade. Upon stimulation, Itk is recruited to the plasma membrane and phosphorylated. Little else is known about how Itk operates inside of mast cells. We find that mast cells lacking Itk are hyperresponsive to FcεR1-mediated activation. This is most apparent in the amount of IL-4 and IL-13 produced in comparison to wild-type mast cells. Increased cytokine production was accompanied by elevated and sustained signaling downstream of the FcεR1. Finally, biochemical evidence demonstrates that Itk is part of an inhibitory complex containing the phosphatase SHIP-1. These results indicate a novel function for Itk as a negative regulator in FcεR1- mediated mast cell activation.

Vector competence of mosquitoes has been linked to the conditions in which the larvae mature to adults. The microbial community obtained from the rearing environment is suspected to be one key factor in this interplay. A better understanding of how the rearing environment affects the gut microbiome and Anopheles-Plasmodium interactions could be useful for understanding observed lab vs. field differences in Plasmodium biology and help drive future control efforts. Currently there is a lack of research done on the differences between lab strain mosquitoes and their rearing environments and how lab mosquitoes differ from wild type mosquitoes. Bridging this gap and studying how rearing habitats change gut microbiomes is critical for optimizing the lab-rearing environment. This thesis focuses on the effects larval rearing has on microbiome establishment and innate immune responses in the common malaria mosquito, Anopheles quadrimaculatus.

Cannabis is widely used for recreational and medicinal purposes. Inhalation of cannabis smoke is the predominant method of drug consumption, exposing the lungs to THC and CBD, as well as a plethora of toxic combustion products. Clinical observations suggest that cannabis smoking contributes to the development of respiratory symptoms and may play a role in the pathogenesis of inflammatory lung disease. However, the association between cannabis smoke, dysregulated pulmonary immunity, and the development of lung disease is inconclusive. To improve our understanding of this relationship, we developed novel mouse models to investigate the effect of cannabis smoke exposure on lung immunity. Using compositionally relevant cannabis strains, we established a mouse model of cannabis smoke exposure and validated that it delivers cannabis smoke by measuring cannabis smoke-associated metabolites in the blood. In our initial lung immune characterization, we demonstrated that acute cannabis smoke exposure induces modest changes to innate immune cellularity in the airways and lung tissue. Specifically, lung macrophage subpopulations were proportionally altered following smoke exposure. As well, we demonstrated that lung disease-associated mediators, including MDC, TARC, and VEGF, were dysregulated in cannabis smoke-exposed lung tissue. In addition to our initial characterization, we established a first-of-its-kind concurrent cannabis smoke exposure and influenza infection model. Using this model, we demonstrated that cannabis smoke exposure exacerbates weight loss following influenza infection. These increases in weight loss corresponded with dysregulated cellular responses and immune mediator expression. Cell types involved in early innate immune signaling, such as macrophages and dendritic cells, were significantly affected by concurrent exposure and infection. Additionally, anti-viral mediators. including IFNγ, IP-10, RANTES, and TNFα, were decreased in cannabis smoke-exposed, infected lung tissue. Collectively, we defined two novel models of cannabis smoke exposure that can be leveraged in future investigations on the inflammatory effects and associated health outcomes of cannabis smoke. / Thesis / Master of Science (MSc) / Cannabis is widely used for recreational and medical purposes. Smoking is the most popular method to consume the drug among users. However, little is understood about the effects of cannabis smoke on lung health, despite evidence suggesting that it may lead to negative health outcomes. To address this gap in knowledge, we developed two unique mouse models of cannabis smoke exposure. Using these models, we explored the effects of cannabis smoke on lung immune responses in healthy and influenza infected mice. Our findings suggested that lung immunity is altered following cannabis smoke exposure. Additionally, we found that overall health was worsened during influenza infection in cannabis smoke-exposed mice. This effect was associated with weakened viral immunity in the lungs. The models we developed and the findings using it thus far create the foundation for future studies on cannabis smoke and lung health.

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This document only includes an excerpt of the corresponding thesis or dissertation. To request a digital scan of the full text, please contact the Ruth Lilly Medical Library's Interlibrary Loan Department (rlmlill@iu.edu).

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