VTechWorks Repository :: Browsing by Author "Leeth, Caroline M."

Browsing by Author "Leeth, Caroline M."

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Approaches for Developing and Implementing Precision Feeding Programs to Maximize Feed Efficiency
Price, Tanner Paige (Virginia Tech, 2020-05-18)
Nutritional management of dairy cattle is of importance to the industry due to its influence on production performance and association with large expenses for producers. Current ration formulation may be improved by predicting feeding recommendations for individual animals, rather than groups of animals, through precision feeding. Automated feeding systems (AFS) designed to deliver individual rations must include response-based models that utilize individual cow production data to make feed recommendations. These models require large data sets of individual cow responses to a variety of nutritional interventions. As a result, an experiment was designed to collect individual response data from 24 Holstein cows fed supplemental top dresses. After analyses, dry matter intake (DMI), milk yield (MY), milk fat yield, milk protein yield, feed efficiency, and activity were significantly affected by top dress (P < 0.001). These results suggest opportunity to use precision feeding to implement economically optimal ration recommendations designed to increase dairy cow production. Therefore, a second experiment was conducted in order to develop and test two algorithms that targeted individualized feeding to increase feed efficiency. Milk protein percentage (P = 0.008) and feed efficiency (P < 0.001) were significantly affected by a 3-way interaction between top dress, algorithm, and week. These results highlight the opportunity for precision feeding to increase the efficiency of individual dairy cows. Although the control group resulted in greater income over feed costs than either of the developed algorithm feeding strategies, algorithm refinement and modification may result in more efficient feeding recommendations that are economically viable.
B-Lymphocytes Expressing an Ig Specificity Recognizing the Pancreatic beta-Cell Autoantigen Peripherin Are Potent Contributors to Type 1 Diabetes Development in NOD Mice
Leeth, Caroline M.; Racine, Jeremy; Chapman, Harold D.; Arpa, Berta; Carrillo, Jorge; Carrascal, Jorge; Wang, Qiming; Ratiu, Jeremy; Egia-Mendikute, Leire; Rosell-Mases, Estela; Stratmann, Thomas; Verdaguer, Joan; Serreze, David V. (American Diabetes Association, 2016-07-01)
Although the autoimmune destruction of pancreatic b-cells underlying type 1 diabetes (T1D) development is ultimately mediated by T cells in NOD mice and also likely in humans, B cells play an additional key pathogenic role. It appears that the expression of plasma membrane–bound Ig molecules that efficiently capture b-cell antigens allows autoreactive B cells that bypass normal tolerance induction processes to be the subset of antigen-presenting cells most efficiently activating diabetogenic T cells. NOD mice transgenically expressing Ig molecules recognizing antigens that are (insulin) or are not (hen egg lysozyme [HEL]) expressed by b-cells have proven useful in dissecting the developmental basis of diabetogenic B cells. However, these transgenic Ig specificities were originally selected for their ability to recognize insulin or HEL as foreign, rather than autoantigens. Thus, we generated and characterized NOD mice transgenically expressing an Ig molecule representative of a large proportion of naturally occurring islet-infiltrating B cells in NOD mice recognizing the neuronal antigen peripherin. Transgenic peripherin-autoreactive B cells infiltrate NOD pancreatic islets, acquire an activated proliferative phenotype, and potently support accelerated T1D development. These results support the concept of neuronal autoimmunity as a pathogenic feature of T1D, and targeting such responses could ultimately provide an effective disease intervention approach.
Control of lupus nephritis by changes of gut microbiota
Mu, Qinghui; Zhang, Husen; Liao, Xiaofeng; Lin, Kaisen; Liu, Hualan; Edwards, Michael R.; Ahmed, Sattar Ansar; Yuan, Ruoxi; Li, Liwu; Cecere, Thomas E.; Branson, David B.; Kirby, Jay L.; Goswami, Poorna; Leeth, Caroline M.; Read, Kaitlin A.; Oestreich, Kenneth J.; Vieson, Miranda D.; Reilly, Christopher M.; Luo, Xin M. (2017-07-11)
Background: Systemic lupus erythematosus, characterized by persistent inflammation, is a complex autoimmune disorder with no known cure. Immunosuppressants used in treatment put patients at a higher risk of infections. New knowledge of disease modulators, such as symbiotic bacteria, can enable fine-tuning of parts of the immune system, rather than suppressing it altogether. Results: Dysbiosis of gut microbiota promotes autoimmune disorders that damage extraintestinal organs. Here we report a role of gut microbiota in the pathogenesis of renal dysfunction in lupus. Using a classical model of lupus nephritis, MRL/lpr, we found a marked depletion of Lactobacillales in the gut microbiota. Increasing Lactobacillales in the gut improved renal function of these mice and prolonged their survival. We used a mixture of 5 Lactobacillus strains (Lactobacillus oris, Lactobacillus rhamnosus, Lactobacillus reuteri, Lactobacillus johnsonii, and Lactobacillus gasseri), but L. reuteri and an uncultured Lactobacillus sp. accounted for most of the observed effects. Further studies revealed that MRL/lpr mice possessed a “leaky” gut, which was reversed by increased Lactobacillus colonization. Lactobacillus treatment contributed to an anti-inflammatory environment by decreasing IL-6 and increasing IL-10 production in the gut. In the circulation, Lactobacillus treatment increased IL-10 and decreased IgG2a that is considered to be a major immune deposit in the kidney of MRL/lpr mice. Inside the kidney, Lactobacillus treatment also skewed the Treg-Th17 balance towards a Treg phenotype. These beneficial effects were present in female and castrated male mice, but not in intact males, suggesting that the gut microbiota controls lupus nephritis in a sex hormone-dependent manner. Conclusions: This work demonstrates essential mechanisms on how changes of the gut microbiota regulate lupusassociated immune responses in mice. Future studies are warranted to determine if these results can be replicated in human subjects.
Dissecting the impact of macrophage migration inhibitory factor (MIF) on host immune response
Park, Myeongseon (Virginia Tech, 2018-10-16)
Macrophage migration inhibitory factor (MIF) has been implicated in mediating both innate and adaptive immune responses in inflammatory and infectious diseases. The sequence and structure of MIF is highly conserved across the avian phylogeny, which underlies high sequence homology and functional similarities between turkey and chicken MIFs. Turkey MIF (TkMIF) inhibited cell migration and promoted cell proliferation with production of inflammatory mediators, comparable to the biological properties of chicken MIF (ChMIF), thus indicating the biological cross-reactivity between turkey and chicken MIFs. This study identified the cell surface receptor(s) that could bind ChMIF and the biological roles triggered by such interactions. In addition to CD74, a previously identified receptor, CXCR4 also interacts with ChMIF. Moreover, the formation of receptor complexes was shown between CXCR4 and CD74. MIF signaling through CXCR4 and CD74 led to cell chemotaxis and proliferation activity as well as intracellular calcium influx. Intriguingly, Eimeria MIF (EMIF), a homologue secreted following parasitic infection, also interacted with CD74 leading to comparable biological functions to those of ChMIF. Given such observations, we hypothesized that CXCR4 and CD74 are receptors for ChMIF leading to the functional consequences similarly manifested by EMIF interaction with the corresponding receptors. EMIF, predominantly secreted from the invasive merozoite stage, may help the parasite exploit the host immune response by interacting with common ChMIF receptors. This may lead to functional mimicry thus provoking the question of whether EMIF would modulate the biological functions of ChMIF to manipulate the host defense that allows more efficient invasion of the host. To evaluate this concept, a transgenic E. tenella lacking MIF was generated by in vivo passage of E. tenella transfected with a CRISPR plasmid targeting EMIF. Although not fully disrupted, reduction of EMIF expression was observed in the transgenic E. tenella itself as well as in inoculated cells, which resulted in enhanced survival of host cells. Herein, we achieved a better characterization of the functional roles of both avian and parasite MIFs underlying the interaction with common host receptors, along with the essential role of parasite MIF promoting host cell death during parasitic infection.
Efficacy of Wearable Therapies on the Ability to Improve Performance and Physical Health in Sport Horses
Schmidt, Therese Elizabeth (Virginia Tech, 2023-04-25)
Equines have been used for utilized for manual labor, recreation, and companionship amongst many other valuable conveniences since their domestication. As the modern horse progressed from livestock to athlete, attention was paid to the body conformation to be used as an indicator of biomechanics and can dictate equine performance. Poor conformation can put physical limitations on the body and predispose the horse to injury and chronic disease. When not managed properly, these flaws can lead to injury, lameness, and premature retirement in sport horses. The distal limb is composed of tendons and ligaments that are all susceptible to tear or rupture. Protective wraps or boots are typically applied to the distal limb prior to exercise to prevent superficial injury from the environment or interference. However, these preventatives can trap heat against the skin which can have detrimental effects on the fibroblasts which can lead to failure. It was not until the early twentieth century that the idea of equine physiotherapy was adopted, and practices changed to meet remedial needs and create a sustainable, healthy equine athlete. Equine physiotherapy is a broad-spectrum term used to describe the therapeutic efforts made to keep the body in good health by means of prevention of injury to improve or maintain performance. Traditionally, therapeutics are administered by a veterinarian or trained professional in the event of an existing injury. In recent years therapeutics have been commercialized and are readily available for everyday preventative use. The most common readily available treatments being variations of pulsating electromagnetic fields (PEMF), vibration therapy, cryotherapy, and thermotherapy. When used prior to or after exercise, the therapeutics are designed to prepare the body for exercise and improve recovery by increasing circulation and down regulating the inflammatory response. The studies performed evaluate the efficacy of Rambo®Ionic (Horseware, Dundalk,Ireland), Lux Ceramic Therapy® (Schneider Saddlery Co., Inc., Ohio, USA), and Ice-Vibe® (Horseware, Dundalk,Ireland) therapeutic boots when applied to the distal limb as per manufacturer recommendation. The first study evaluated the therapeutic boots ability to alter performance performing gait analysis using the ALOGO™ MovePro (Alogo Technologies, Switzerland) stride sensor, blood analysis measuring serum concentrations of C reactive protein (CRP), basic fibroblast growth factor (bFGF) and tenascin-C (TN-C), and capturing thermal images of the distal limb using an HT-19 thermal imaging camera (HTI, La Vergne, TN). In this study, eight healthy horses were exercised for approximately ten minutes per day for five consecutive days. There was a ten-day washout period where the horse received no treatment between each period; there was a total of four periods. The second study only evaluated Rambo®Ionic (Horseware, Dundalk,Ireland) and Ice-Vibe® (Horseware, Dundalk,Ireland) therapeutic boots on seventeen healthy horses in the Virginia Tech equitation lesson program. There were three periods with five days of consecutive data collection and a ten-day washout period in between where the horses received no treatment. Gait analysis was measured using the ALOGO™ MovePro (Alogo Technologies, Switzerland) stride sensor and a blind behavioral analysis was performed to analyze behavioral changes under saddle in response to a rider.
Engrafting Horse Immune Cells into Mouse Hosts for the Study of the Acute Equine Immune Responses
Leeth, Caroline M.; Adkins, Janie; Hay, Alayna N.; Bogers, Sophie Helen; Potter, Ashley; Witonsky, Sharon G.; Zhu, Jing (MDPI, 2021-10-14)
Immunological studies in the horse are frequently hampered by lack of environmental control, complicated study design, and ethical concerns when performing high risk studies. The purpose of the current study was to investigate the utility of a xenograft model for studying acute equine immune responses. Immunocompromised non obese diabetic (NOD). sudden combined immunodeficiency (scid).gamma-/- (NSG) mice were engrafted with either equine peripheral blood lymphocytes (PBLs) or equine bone marrow to determine an optimal protocol for equine lymphocyte engraftment. We found that both PBL and bone marrow grafts populated the host mice successfully. Bone marrow transplants were technically more challenging and required further processing to retard graft versus host disease. Graft vs host disease was apparent at 28 days post-PBL transfer and 56 days post-bone marrow transfer. The results of these studies support the use of mouse hosts to study acute equine immune responses and that different engraftment techniques can be used depending on the experimental design.
Equine Protozoal Myeloencephalitis: investigating immunopathogenesis and treatment efficacy in mouse models and clinically affected horses
Hay, Alayna N. (Virginia Tech, 2020-01-09)
Equine protozoal myeloencephalitis (EPM), predominantly caused by the protozoa Saracocystis neurona, is a common neurologic disease in horses from North America. Equine exposure to the parasite occurs frequently as the protozoa is excreted in opossum (Didelphis virginiana) feces and contaminates the horse's environment. However, clinical neurologic disease only emerges in a small fraction of exposed horses. The seemingly protective immune response that develops in some exposed horses but not all is not fully defined. Previous reports utilizing horse EPM models and immune compromised mouse models, which develop disease simulating EPM after infection with S. neurona, have reported a role of T-lymphocytes and the cytokine interferon gamma, in disease protection. As part of this dissertation, the role of T-lymphocytes and IFNγ was further elucidated. It was determined that IFNγ production is essential for T-lymphocytes to offer protection against S. neurona induced encephalitis, in immune compromised mice. Another factor hindering prognosis of EPM affected horses is treatment failure. The efficacy of the antiprotozoal decoquinate, was tested and found to be ineffective at preventing S. neurona encephalitis, in immune compromised mice. However, the antiprotozoal, diclazuril, was found to be effective at preventing S. neurona encephalitis in immunocompromised mice but once treatment was terminated, infection persisted, and neurologic disease developed. In-situ methods were employed to extensively evaluate the immunopathology of spinal cord tissue samples collected from EPM affected horses. A novel in-situ hybridization technique was successfully utilized to identify S. neurona in tissue samples collected from horses with EPM. This technique will create new opportunities for investigating the immunopathology of EPM. Overall results from the studies conducted in this dissertation suggest that IFNγ production from T lymphocytes is essential for them to offer protection against S. neurona encephalitis. Additionally, further insight on FDA approved and non-FDA approved treatment options for S. neurona infection was gained through the use of the B6Ifnγ -/- mouse model. Collectively, these studies expanded on the knowledge of an understudied equine neurologic disease.
Genetic and Maternal Factors Underlying Early Milk Production and Their Influence on Calf Health
Nin-Velez, Alexandra Irma (Virginia Tech, 2020-09-11)
The quality of early milk produced by dams is affected by various factors (i.e. breed, age, parity, environment, nutrition, management). The impact of these factors on the quality of milk then have subsequent effects on calf health and development. Producers are responsible for following guidelines in order to ensure that they feed calves optimal quality milk in order to produce a healthy animal. They can also regulate factors such as environment and nutrition of the dam in order to produce better quality early milk. However, even after maximizing these factors there is still high mortality rate among pre-weaned calves, therefore, other factors such as mode of birth and genetics need to be studied to determine impacts on early milk quality and make further improvements to calf health and decrease mortality. Two experiments were conducted in order to study the effects of maternal and genetic factors on early milk production and to determine relationships that exist with calf health. The objective of the first study was to determine the effects that the mode of delivery had on early milk composition, and on the rumen microbiome of calves. We hypothesized that mode of birth would impact early milk composition, and, in turn, influence the microbial phyla in the calf gut. The second study had three objectives: 1) establish phenotypic relationships between colostrum composition traits, milk production traits, and calf health, 2) determine impact of breed and season on colostrum production and 3) ) elucidate the genetic parameters (i.e. heritability, genotypic, and phenotypic correlations) among colostrum production and milk production We hypothesized that colostrum composition and production differ among breeds and by season and that individual components influence calf health. Additionally, we hypothesized that colostrum quality traits (i.e. Brix score and volume) are heritable. For the first study Charolaise (CHAR; n = 23) and Angus (ANG; n = 15) dams were divided into two experimental groups; dams underwent vaginal (VD; n= 25) or cesarean (CD; n= 13) deliveries. Early milk samples were collected and quantified for protein, lactose, somatic cell count, and fatty acid concentrations. After parturition calves were separated based on dams experimental group. Rumen fluid was collected from calves on d 1, 3, and 28 post-partum. Extracted DNA from fluid were used for metagenomic sequencing (ANG calves, n=11; CHAR calves, n=13). Samples were run on the HiSeq 2500 platform as paired end reads according to Ilumina's standard sequencing protocol. A regression analysis was done in SAS using PROC GLM and regressing mode of birth on milk components for d 1,3, and 28. After, milk components found to be significantly impacted by mode of birth were regressed against microbial counts. Results showed that VD dams were more likely to have increased (P  0.05) protein, solids non-fat, and lactose on d 1 and 3, but decreased (P < 0.05) urea concentrations. Similarly, short, medium, and long-chain fatty acids were increased (P  0.05) in VD d 3 milk. Changes in true protein elicited a decrease (P  0.05) in rumen fluid Actinobacteria and Proteobacteria; whereas, both solids non-fat and lactose were associated with an increased (P  0.05) response in d 1 transition milk. No significant results for d 28 of sampling were observed. Based on our results we suggest that mode of birth influences protein concentrations in early milk. However, only a slight impact on the overall dynamics of the calf rumen was observed with the microbiome remaining relatively stable on the phyla level in response to changes in protein concentration. The second study looked into relationships between colostrum composition traits, management practices, and calf health, as well as determined heritability and genetic correlations for colostrum quality traits. Values for test-day milk, protein, fat, and somatic cell count (SCS) for Holstein (HO, n= 250) and Jersey (JE, n=289) cows were obtained from the Animal Genomic and Improvement laboratory server at the USDA. Brix score, colostrum weight, dam age, parity, and 3-month season of calving were also recorded. After, colostrum samples from JE cows were sent to DHIA where compositional measurements were obtained (i.e. true protein, fat, lactose, SCS, solid non-fats). Lactoferrin concentration for JE colostrum samples was also determined via ELISA. Calf blood samples were collected within 72 h post-partum and total serum protein (TSP) quantified to determine success of passive immunity transfer. Additionally, farm staff were instructed to record colostrum source for 1st feeding (i.e. dam, mix, other), freshness for 1st feeding (frozen vs fresh), Brix score of colostrum fed, volume of colostrum fed, and birth weight. A PROC Mixed with LSMEANS was performed in SAS to determine relationships between colostrum components, test day components, and quality traits for season, breed, and the interaction between season and breed. Also, PROC Mixed with LSMEANS was used to determine relationships of calf health with environment, management, and colostrum components. Additionally, a Pearson correlation was used to determine relationships between colostrum components and quality traits. Results for Holstein and Jersey showed that both colostrum Brix and volume (P < 0.001) differed by breed. Colostrum volume (P < 0.001), lactose (P < 0.001), and lactoferrin (P = 0.002) varied significantly by season. Additionally, test day milk (P = 0.046), fat (P = 0.012), and protein (P = 0.003) varied significantly by season. Moreover, a significant season and breed interaction (P = 0.028) was observed solely for colostrum volume. Calf health models indicated that TSP, colostrum total protein and solid non-fats impacted incidence of respiratory illness, but no factor significantly impacted incidence of scours. Results for Pearson correlation indicated strong correlations between true protein and solid non-fats and Brix (r = 0.99; 0.86). Lactoferrin also had moderate negative correlations with volume and lactose (r = -0.35; -0.33). Heritability and repeatability's were calculated using BLUPF90 family of programs. A single-trait repeatability animal model was used and included a 1-vector phenotype (Brix or Colostrum weight), fixed effects (i.e. calving year, parity, 3-month season of calving, and age at calving), additive genetic variance, random permanent environment effects, and random residual effects. A series of bivariate models were used to calculate genetic correlations of Brix score and colostrum weight with test-day compositional traits. Heritability estimates results for Holstein cow Brix and colostrum weight, were 0.25 and 0.15. Jersey cow heritability estimates were 0.36 and 0.47 respectively. We also observed some significant genetic correlations with Holstein Brix score and test-day milk (-0.23), fat (0.54), and SCS (0.29) having moderate correlations. Holstein colostrum weight had a strong correlation with test-day milk (0.96). Jerseys had strong genetic correlation of Brix score with colostrum weight (-0.98). Low to moderately heritability was observed for Brix score and colostrum weight in both breeds making them receptive to genetic selection in order to improve breeding programs. In conclusion, mode of birth significantly impacted colostrum composition which had subsequent effects on abundance of rumen microbiota. Colostrum Brix and volume were impacted by breed, season, and interaction, and calf incidence of disease was impacted by colostrum composition and environment. Additionally, two factors influencing colostrum quality (Brix score and colostrum weight) were found to be low to moderately heritable and have moderate to strong genetic correlations to compositional traits. Strong significant relationships were also found between colostrum compositional traits and colostrum quality traits. Therefore, incorporating quality traits into breeding programs has the potential to influence compositional traits which, in turn, can impact calf health and development by the interactions that exist between composition and microbial abundance in the rumen.
Identification and evaluation of Limosilactobacillus reuteri as an inducer of neonatal IgA and autoimmunity
Swartwout, Brianna Kendall (Virginia Tech, 2021-06-22)
Perturbing gut microbiota early in life can lead to the development of autoimmunity. We are just beginning to unravel how early immune programming by microbiota may have long-term effects on noncommunicable diseases. In this thesis, we lay groundwork for programming of the immune system by commensal bacteria early in life through our studies on the induction of early endogenous neonatal IgA, and we evaluate Limosilactobacillus reuteri's characteristics as an inducer. Garnering attention for use a probiotic, L. reuteri has many proven health promoting benefits, such as IgA induction, but emerging evidence also links specific strains to autoimmune disease. "Super-induction" of neonatal IgA can be achieved through cross-fostering immunocompetent pups on immunocompromised dams. We found that this phenomenon was categorically due to transferal of microbes from dam to offspring. By comparing strain CF48-3A to the non-gastric-related organism L. oris, we discovered that L. reuteri is a microorganism that can enhance early neonatal IgA induction. Further investigations revealed that the ability to induce neonatal IgA is not ubiquitous in all L. reuteri strains, as ATCC PTA 6475 did not significantly elevate IgA. We discovered that 6475 has the antigenic ability to stimulate B cell differentiation and IgA production, but it is suppressed by a mechanism related to differences in surface architecture of this strain. L. reuteri strains also vary in their potency of aryl hydrocarbon receptor (AhR) stimulation. In mice, activation of AhR during gestation by a potent prototypical ligand, TCDD, leads to development of autoimmunity offspring. We found that TCDD exacerbated autoimmunity in adult mice using a strain of mice with similar AhR affinity to humans. Further investigations can clarify whether differential AhR ligand expression between L. reuteri strains contributes to the relationship between L. reuteri and autoimmunity. Overall, we conclude that differences between strains of L. reuteri have profoundly different immunological consequences that contribute to our understanding of the linkage between strains and autoimmunity.
Interleukin 6 Accelerates Mortality by Promoting the Progression of the Systemic Lupus Erythematosus-Like Disease of BXSB. Yaa Mice
Jain, Shweta; Park, Giljun; Sproule, Thomas J.; Christianson, Gregory J.; Leeth, Caroline M.; Wang, Hongsheng; Roopenian, Derry C.; Morse, Herbert C. III (PLOS, 2016-04-06)
IL6 is a multifunctional cytokine that drives terminal B cell differentiation and secretion of immunoglobulins. IL6 also cooperates with IL21 to promote differentiation of CD4+ T follicular helper cells (TFH). Elevated serum levels of IL6 correlate with disease flares in patients with systemic lupus erythematosus (SLE). We previously reported that IL21 produced by TFH plays a critical role in the development of the SLE-like disease of BXSB.Yaa mice. To examine the possible contributions of IL6 to disease, we compared disease parameters in IL6-deficient and IL6-competent BXSB.Yaa mice. We report that survival of IL6-deficient BXSB.Yaa mice was significantly prolonged in association with significant reductions in a variety of autoimmune manifestations. Moreover, B cells stimulated by co-engagement of TLR7 and B cell receptor (BCR) produced high levels of IL6 that was further augmented by stimulation with Type I interferon (IFN1). Importantly, the frequencies of TFH and serum levels of IL21 were significantly reduced in IL6-deficient mice. These findings suggest that high-level production of IL6 by B cells induced by integrated signaling from the IFN1 receptor, TLR7 and BCR promotes the differentiation of IL21-secreting TFH in a signaling sequence that drives the lethal autoimmune disease of BXSB.Yaa mice.
The modulation of autoimmune disease progression in mouse models
Zhu, Jing (Virginia Tech, 2020-11-25)
B cells play crucial roles in the development of the two human autoimmune diseases, type 1 diabetes (T1D) and systemic lupus erythematosus (SLE). In the past decade, numerous studies showed positive responses of B cell depletion therapies in these two diseases. However, the beneficial effects are temporary and accompanied with adverse events. In this dissertation, we aimed to identify novel targets for a better modulation of disease development using mouse models. These diseases have circulating autoantibodies that are mostly mutated with an IgG isotype, indicating B cells that are producing them have been through the process of affinity maturation. Activation-induced cytidine deaminase (AID) is a core enzyme that regulates somatic hypermutation (SHM) and class switch recombination (CSR), the two key mechanisms in affinity maturation. We showed that genetic ablation of AID significantly inhibited the development of TID in NOD mice. Homologous recombination (HR) pathway is important for the repair of AID-induced DNA double strand breaks during CSR. 4,4'-Diisothiocyano-2,2'-stilbenedisulfonic acid, also known as DIDS, is a small molecule that inhibits HR pathway and subsequently leads to apoptosis of class switching cells. DIDS treatment remarkably retarded the progression of TID, even when started at a relatively late stage, indicating the potential of this treatment for disease reversal. In both approaches, we observed a notable expansion of CD73+ B cells, which exerted an immunosuppressive role and could be responsible for T1D resistance. Next we examined the effect of targeting affinity maturation through these two approaches in lupus-prone mice. The genetic abrogation of AID in BXSB mice significantly ameliorated lupus nephritis and prolonged their lifespan. AID-deficient mice also exhibited improvement on disease hallmarks with increased marginal zone B cells and more normal splenic architecture. DIDS treatment notably reduced class switching when B cells were stimulated in vitro. However, the administration of DIDS did not strikingly alter the course of SLE in either BXSB mice or MRL/lpr mice. These findings demonstrated that affinity maturation could be a potential target for T1D and SLE, while further explorations into targeting other components in the repair pathway are warranted for SLE. Lastly, we assessed the effect of maternal AID modulation on the SLE development in the offspring using BXSB mouse model. Interestingly, the absence of maternal AID resulted in offspring that developed significantly more severe lupus nephritis compared to control. The offspring born to AID-deficient dams also exhibited elevated levels of pathogenic autoantibodies and exacerbated disease features. Therefore, the modulation of maternal AID could influence the SLE development in the offspring, and future investigations are needed to determine the underlying mechanisms responsible for the disease acceleration.
TLR4 expression on equine B lymphocytes: a clue to LPS sensitivity?
Kasmark, Leah (Virginia Tech, 2017-11-09)
Horses are prone to potentially lethal endotoxemia due to their surrounding fecal containing environment and their predisposition to colic. Their gastrointestinal tract and feces naturally contain gram-negative bacteria. These bacteria express lipopolysaccharide (LPS) on their cell membranes, which is recognized by Toll-like receptor 4 (TLR4). In cases where epithelial barriers are compromised or breached LPS has the potential to enter circulation and cause the inflammatory symptoms seen with endotoxemia. The objective of this study was to determine TLR4 presence and functionality on equine B cells. TLR4 expression on B lymphocytes has been studied in mouse, human and many other mammals, but has not been well characterized in the horse. Humans are highly sensitive to LPS but their B cells express non-functional TLR4. Mice in contrast are highly tolerant of LPS yet their B cells express functional TLR4. Studies in horse have perhaps been limited by the limited array of antibody markers available for use in horse. Anti-human CD21 has previously been shown to mark equine B lymphocytes. We show rat anti-mouse CD45R(B220) mAbs also accurately labels equine B lymphocytes. To investigate TLR4 expression in horses 12 Thoroughbred geldings, ages 5-10, were used for blood collection. By using the density gradient, Lympholyte, lymphocytes were separated from peripheral blood and incubated with or without LPS. B lymphocyte proliferation, TLR4 expression and mRNA changes were examined before or after culture in the presence or absence of LPS. We demonstrate TLR4 is expressed on equine B lymphocytes through the use of a mouse anti-human TLR4 antibody, clone 76B357.1, not previously used in horse. We demonstrated equine B cells fail to proliferate under LPS challenge as opposed to highly proliferative mouse B lymphocytes. However, transcriptional changes were observed in the equine cells within the TLR4 pathway upon treatment with LPS.
Wearable Devices for Improved Equine Welfare
Naughton, Samantha Grace (Virginia Tech, 2023-03-17)
The use of digital technology is becoming increasingly popular in equine research. Current applied technologies for livestock are being used to detect pathogens, observe locomotion patterns, determine estrus periods, and measure vital parameters. These sensors leverage global positioning systems, accelerometers, magnetometers, goniometers, optics, among other emerging sensing technologies. The success of these devices has led to the introduction of various equine wearable sensors into market. These technologies seek to promote mobile devices to be used in equine training, monitoring, and clinical contexts. Therefore, the objective of this research is to characterize advancements, opportunities, and gaps in our existing knowledge of equine wearable sensor technology. Specifically, this research explores two innovative sensors designed for equines and their potential to enhance animal safety and health. The purpose of the research on these sensors is to (1) better contextualize biomechanical data in practically applicable terms and (2) evaluate the accuracy of a photoplethysmography based pulse sensor to detect heart rates of adult horses. In addition, currently marketed equine wearable sensors are reviewed, and their limitations are evaluated. Areas of future research and developments of equine wearable technologies are also explored.

Browsing by Author "Leeth, Caroline M."

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