A role played by sex in innate immune memory and disease severity

While immunological memory has traditionally been understood to be solely within the purview of adaptive immunity, recent evidence has shown that a type of "memory" exists in innate immune cells, as a prior insult can lead to enhanced subsequent pro-inflammatory activity, such as cytokine release, against a broad range of secondary stimuli. However, innate immune responses can differ between females and males, as sex hormones can augment or reduce activity. This dissertation examines the influence of the female sex hormones 17?-estradiol and progesterone on innate immune memory, or 'trained immunity'. We hypothesized that progesterone would attenuate trained secondary responses. To this end, we found that infection by the opportunistic bacterium Burkholderia gladioli decreased survival in trained female adaptive immune- deficient mice, and that female mouse serum significantly attenuated trained secondary responses. This effect varied with serum from the different stages of the mouse estrous cycle and correlated with higher progesterone levels. We further showed that exogenous progesterone decreased trained responses, and glycolytic activity underlying trained immunity, while blocking its cognate nuclear receptor restored activity and rescued trained female mice from infection to the level of protection seen in males. This work suggests that the naturally cycling variability in progesterone levels may affect trained immunity and even protection against infections, possibly even during pregnancy though further studies are needed. This is the basis for a mechanism by which males can produce greater average trained immune responses than females, which protected males from opportunistic B. gladioli infection, but oppositely, might correlate with increased male morbidity from coronavirus disease 2019 (COVID-19). In early 2020, the COVID-19 viral pandemic shut down schools worldwide, although classes resumed in the Fall semester. We sought to track antibody seropositivity in the University of Missouri population during that semester, paying special attention to demographics including sex. As expected, antibody- positive cases increased throughout the duration of the semester, particularly among students. Older individuals, especially older men, had higher antibody concentrations after infection compared to women, although these levels declined more rapidly than those of women over time. We can correlate these observations with worldwide studies concluding that during the pandemic, men were shown to be more susceptible to severe morbidity and mortality than women, on average. We proposed application of an existing drug to attempt to alleviate morbidity in the most severe COVID-19 cases. COVID-19 is primarily a respiratory disease caused by a viral pathogen. Many severe respiratory viral infections, including influenza, are often characterized by high neutrophil infiltration into the lungs and production of neutrophil extracellular traps (NETs), comprised of DNA and inflammatory enzymes, which can clog the respiratory tracts. We hypothesized that severe COVID-19 patients had high lung neutrophil counts and NETs; and that treatment with the cystic fibrosis drug, dornase alfa, which breaks apart these clogging NETs, would improve disease outcomes. Indeed, we found that dornase alfa decreased NETs in the lungs and also improved lung characteristics in treated patients. Though we did not design the clinical trial to assess sex differences in our small cohort (n = 10 patients), together with the sex differences observed in the large data set sampling the MU community, and those reported worldwide, these findings imply an outsized role for innate immunity in severe respiratory infections. Although unexplored here, it is conceivable that training of innate cells and their precursors may have influenced immune hyperresponsiveness in COVID-19.Includes bibliographical references

Endotracheal tube-induced sore throat pain and inflammation is coupled to the release of mitochondrial DNA

In the absence of infection, the pathophysiology of endotracheal tube-induced sore throat pain is unclear. Activated neutrophils release elastase, reactive oxygen species, and inflammatory cytokines known to contribute to neuropathic pain. Sterile tissue injury can cause the release of damage-associated molecular patterns such as mitochondrial DNA that promote neutrophil activation. We hypothesized that endotracheal tube-induced sore throat pain is linked to mitochondrial DNA-mediated neutrophil inflammation. A nonrandomized prospective survey for sore throat pain was conducted in 31 patients who required short-term intubation and had no evidence of upper airway infection. Patterns of neutrophil abundance, activation, and mitochondrial DNA levels were analyzed in tracheal lavage fluid following intubation and prior to extubation. Thirteen of 31 patients reported sore throat pain. Sore throat patients had high neutrophilia with elevated adhesion molecule and TLR9 expression and constitutive reactive oxygen species generation. Tracheal lavage fluid from sore throat patients accumulated mitochondrial DNA and stimulated neutrophils to release mediators associated with pain in a TLR9- and DNAse-dependent fashion. Endotracheal tube-induced sore throat is linked to the release of mitochondrial DNA and can drive TLR9-mediated inflammatory responses by neutrophils reported to cause pain. Mitigating the effects of cell-free mitochondrial DNA may prove beneficial for the prevention of endotracheal tube-mediated sore throat pain

Immunization of Chickens with Newcastle Disease Virus Expressing H5 Hemagglutinin Protects against Highly Pathogenic H5N1 Avian Influenza Viruses

Highly-pathogenic avian influenza virus (HPAIV) and Newcastle disease virus (NDV) are the two most important poultry viruses in the world. Natural low-virulence NDV strains have been used as vaccines over the past 70 years with proven track records. We have previously developed a reverse genetics system to produce low-virulent NDV vaccine strain LaSota from cloned cDNA. This system allows us to use NDV as a vaccine vector for other avian pathogens.Here, we constructed two recombinant NDVs (rNDVs) each of which expresses the hemagglutinin (HA) gene of HPAIV H5N1 strain A/Vietnam/1203/2004 from an added gene. In one, rNDV (rNDV-HA), the open reading frame (ORF) of HA gene was expressed without modification. In the second, rNDV (rNDV-HAF), the ORF was modified so that the transmembrane and cytoplasmic domains of the encoded HA gene were replaced with those of the NDV F protein. The insertion of either version of the HA ORF did not increase the virulence of the rNDV vector. The HA protein was found to be incorporated into the envelopes of both rNDV-HA and rNDV-HAF. However, there was an enhanced incorporation of the HA protein in rNDV-HAF. Chickens immunized with a single dose of either rNDV-HA or rNDV-HAF induced a high titer of HPAIV H5-specific antibodies and were completely protected against challenge with NDV as well as lethal challenges of both homologous and heterologous HPAIV H5N1.Our results suggest that these chimeric viruses have potential as safe and effective bivalent vaccines against NDV and. HPAIV. These vaccines will be convenient and affordable, which will be highly beneficial to the poultry industry. Furthermore, immunization with these vaccines will permit serological differentiation of vaccinated and avian influenza field virus infected animals

Study 1 (Earhart & Tarter): Describing Tropical Termite Nest Growth and Decline Patterns Using Logistic Growth Models

Describing tropical termite nest growth and decline patterns using logistic growth models Termites act as ecosystem engineers, capable of recycling most dead organic material and maintaining the flow of resources in a tropical ecosystem; this characteristic may be especially important on St. John, USVI, where the arboreal nesting termite, Nasutitermes acajutlae is the major invertebrate degrader. Our goal is to investigate nest growth, decline, and longevity on St. John, as well as to understand how biotic and abiotic factors affect changes in nest size and survival, via mathematical models. We have collected natural history data on \u3e200 N. acajutlae nests from five major habitat types (dry, mangrove, moist, sparse, wooded/wetlands) spanning the years 1998-2012. We developed an adaptive logistic model using nest volumes from these years capable of describing the patterns of nest growth and decline from year to year for each habitat. We observed that growth and decline, and general nest size patterns were typically unrelated between habitats. However, each habitat has its own typical pattern of growth and decline. Using this model, it is possible to estimate when nests first appeared and their likely longevity, enabling us to effectively determine the average nest lifespan for each habitat. In the future, we will incorporate both abiotic (i.e., ambient humidity and ambient temperature) variables, and intrinsic biotic (e.g., production of alates) to estimate their affects on nests in each habitat. This will allow us to predict the efficacy of termite degradation in tropical ecosystems in changing environmental conditions

Mitochondrial DNA induces Foley catheter related bladder inflammation via Toll-like receptor 9 activation

Abstract Bladder instrumentation engages the innate immune system via neutrophil activation, promoting inflammation and pain. Elevated levels of mitochondrial DNA (mtDNA) have been associated with tissue damage and organ dysfunction. We hypothesized that local bladder trauma induced by a Foley catheter (FC) will result in mtDNA release, migration of neutrophils into the bladder lumen, and activation of the Toll-like receptor 9 (TLR9) and nuclear factor kappa B (NF-κB) pathway leading to bladder tissue damage. We randomized 10 swine into two groups receiving uncoated, or chloroquine/N-Acetylcysteine (CQ/NAC)-coated FCs. Urine samples were analyzed for mtDNA activation of TLR9/NF-κB as demonstrated by indicators of neutrophil adhesion, migration, and activation. We found that uncoated FCs resulted in a unique active neutrophil phenotype that correlated with bladder epithelial injury, neutrophilia, necrosis, mtDNA release, TLR9/NF-κB activation, transcription and secretion of pro-inflammatory cytokines, and enhanced respiratory burst. In our study we observed that the high levels of mtDNA and elevated TLR9/NF-κB activity were ameliorated in the CQ/NAC-coated FC group. These findings suggest that post-migrated bladder luminal neutrophils are involved in local tissue damage and amelioration of the mtDNA/TLR9/NF-κB inflammatory axis may represent a therapeutic target to prevent inflammation, and bladder tissue injury

Lower female survival from an opportunistic infection reveals progesterone-driven sex bias in trained immunity

Summary: Immune responses differ between females and males, although such sex-based variance is incompletely understood. Observing that bacteremia of the opportunistic pathogen Burkholderia gladioli caused many more deaths of female than male mice bearing genetic deficiencies in adaptive immunity, we determined that this was associated with sex bias in the innate immune memory response called trained immunity. Female attenuation of trained immunity varies with estrous cycle stage and correlates with serum progesterone, a hormone that decreases glycolytic capacity and recall cytokine secretion induced by antigen non-specific stimuli. Progesterone receptor antagonism rescues female trained immune responses and survival from controlled B. gladioli infection to magnitudes similar to those of males. These data demonstrate progesterone-dependent sex bias in trained immunity where attenuation of female responses is associated with survival outcomes from opportunistic infection