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The contamination of corn (maize) by fungi and the accumulation of mycotoxins are a serious agricultural problem for human and animal health. One particular devastating group of mycotoxins, called aflatoxins, has been intensely studied since the 1960s. Studies of Aspergillus flavus, the agriculturally relevant producer of aflatoxins, have led to a well-characterized biosynthetic pathway for aflatoxin production, as well as a basic understanding of the organism’s life cycle. Unfortunately, these efforts have not resulted in corn production practices that substantially reduce aflatoxin contamination. Similarly, the use of agrochemicals (e.g., fungicides) results in very limited reduction of the fungus or the toxin. Thus, cultural management (fertility and irrigation) coupled with aggressive insect management is current recommendation for integrated aflatoxin management. The development of resistant hybrids appears to be a very promising technology, but commercial hybrids are still not available. Thus, biocontrol appears to be the most promising available avenue of reducing aflatoxin accumulation. Biocontrol utilizes nontoxigenic strains of Aspergillus to reduce the incidence of toxin-producing isolates through competitive displacement. To maximize the effectiveness of biocontrol, a thorough knowledge of the environmental factors influencing colonization and growth of Aspergillus is needed. A. flavus not only colonizes living plant tissue, but it also grows saprophytically on plant tissue in the soil. These residues serve as a reservoir for the fungus, allowing it to overwinter, and under favorable conditions it will resume growth and release new conidia. The conidia can be transmitted by air or insects to serve as new inoculum on host plants or debris in the field. This complex ecology of Aspergilli has been studied, but our understanding lags behind what is known about biosynthesis of the toxin itself. Our limited understanding of Aspergilli soil ecology is in part due to limitations in evaluating Aspergilli, aflatoxin, and the biosynthetic genes in the varying aspects of the environment. Current methods for assessing Aspergillus and aflatoxin accumulation rely heavily on cultural and analytical methods that are low throughput and technically challenging. Thus to understand Aspergillus ecology and environmental effects in contamination to maximize biocontrol efforts, it is necessary to understand current treatment effects and to develop methodologies capable of assessing the fungal populations present. In this manuscript we discuss the current knowledge of A. flavus ecology, the application of selected molecular techniques to field assessments, and crop practices used to reduce aflatoxin contamination, focusing on chemical treatments (fungicides and herbicides), insect management, and crop management. [ABSTRACT FROM AUTHOR]

Immune literacy garnered significant attention in recent years due to the threat posed by emerging infectious diseases. The pace of immunological discoveries and their relevance to society are substantial yet coordinated educational efforts have been rare. This motivated us to create a task force of educators to reflect on pedagogical approaches to teaching immunology and to draft, develop, and evaluate key competencies for undergraduate immunology education. The research questions addressed include: 1) Which competencies are considered important by educators? 2) Are the illustrative skills clear, accurate and well aligned with the core competencies listed in the Vision and Change report?; 3) What are the concerns of immunology educators about competencies and skills? We collected data on the draft competencies using surveys, focus groups, and interviews. The iterative revision phase followed the community review phase before finalizing the framework. Here, we report a hierarchical learning framework, with six core competencies, twenty illustrative skills, and companion immunology-specific example learning outcomes. Predominant themes from interviews and focus groups, which informed revisions of this framework are shared. With the growing need for immunology education across the sciences, the ImmunoSkills Guide and accompanying discussion can be used as a resource for educators, administrators and policymakers., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Pandey et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

The interdisciplinary nature of immunology can make studying not only engaging but also challenging, as understanding immunologic processes and immune system components requires foundational knowledge from several science disciplines. The University of Alabama at Birmingham has a unique, 4-year, Undergraduate Immunology Program (UIP) that provides a comprehensive curriculum in immunology that includes five core courses starting in the second year, at which point, students are in the process of completing basic science sequences. For this study, students in courses across the UIP curriculum were asked to identify basic science topics that relate to four immunology concepts. In addition, students were surveyed on their confidence in understanding each of the basic science topics and were asked to identify the course in which they felt that they had fully learned the topic. Data from this study did not demonstrate a change in students' interdisciplinary science competency from the second to fourth year. Importantly, students reported that they fully understood 11 out of 12 basic science concepts in courses offered in their first and second years, with confidence in basic science topics significantly improving from the second to third year. The lack of demonstrated improvement in interdisciplinary understanding across the curriculum may be attributed to the fact that students are able to integrate basic science topics with foundational immunologic concepts as early as their second year. Importantly, these findings suggest that the integration or review of basic science topics in an immunology course may improve students' comprehension of foundational immunology concepts and interdisciplinary science competency., (© 2024 The Author(s). Immunology & Cell Biology published by John Wiley & Sons Australia, Ltd on behalf of the Australian and New Zealand Society for Immunology, Inc.)

Immunology is inherently interdisciplinary. Understanding how the immune system functions requires knowledge from several scientific disciplines, including molecular biology, cellular biology, genetics, and biochemistry. Furthermore, immunology is conceptually complex, requiring the identification of a plethora of immune components and mastery of a large volume of new vocabulary. These attributes can pose challenges to student learning in the undergraduate immunology classroom. Team-based learning (TBL) is a pedagogical method used to increase student engagement in learning, improve student collaboration, and develop communication skills. In a variety of educational settings, TBL activities have been shown to foster a deeper understanding of complex topics, increase student confidence in course content, and improve learning outcomes. In this study, we examined differences in the impact of traditional lecture versus TBL activities on student learning outcomes for four different topics presented in an undergraduate adaptive immunity course composed largely of academically high-performing students. We matched content across two student cohorts, delivered via team-based learning methodology (T cell development and Ab-mediated functions) and traditional lecture (B cell development and T cell effector functions). Student learning was assessed using content questions across a range of Bloom's taxonomy levels, which demonstrated that the TBL activities did not improve examination performance over lecture-based learning in this course. However, students found this learning tool to be valuable, indicating that the TBL activities assisted with preparation for examinations and provided a necessary opportunity to address misconceptions., (Copyright © 2024 The Authors.)

Teaching and learning complex molecular cascades can often be challenging. In immunology, students struggle to visualize immunological processes, such as activation of the complement system, which involves three separate cascades leading to multiple effector functions. Offering learning activities that use tangible modeling can help students learn conceptually difficult content by fostering a visual understanding of concepts, as well as instill confidence and interest in the material. In this article, we describe a learning activity using LEGO bricks that demonstrates the activation of the classical, lectin, and alternative complement pathways and formation of the membrane attack complex. In both an introductory and advanced immunology course, we investigated the effect of the activity on student learning and subject confidence. Performance on examination questions about complement demonstrated that the LEGO activity improved learning in a naive student population (students in introductory immunology), but not in a previously informed student population (students in advanced immunology). In addition, self-reported confidence in the content was significantly higher in students who completed the LEGO activity in the advanced course, but not the introductory course, compared with those who did not do the activity. Students in both courses who did the activity had a positive perception of the activity, with a majority of students reporting that they enjoyed the activity and had more interest in the complement system., (Copyright © 2022 The Authors.)

The need to focus on immunology education has never been greater. The coronavirus disease 2019 pandemic has revealed that a significant proportion of our society is vaccine hesitant. Some of this hesitancy may stem from a general lack of understanding of how the immune system and immunological interventions work. In addition, social media platforms undercut public health efforts by quickly propagating a multitude of misconceptions and erroneous information surrounding the science behind these interventions. The responsibility to be advocates for science is well recognized by immunology researchers, educators, and public health professionals, as evidenced by the rich body of resources developed to communicate science to the lay audience. Scientific jargon, however, can be a barrier to effective communication and can negatively impact learning and comprehension. The field of immunology is especially laden with discipline-specific terminology, which can hamper educators' efforts to convey key concepts to learners. Furthermore, a lack of consistency in accepted definitions can complicate students' conceptual understanding. Learning resources, including textbooks, published in print or available online, and exclusively digital resources, continue to serve as the primary sources of information for both educators and students. In this article, we describe a vast heterogeneity in learning resource glossary descriptions of two key conceptual terms: antigen and immunogen We provide a perspective on pedagogical strategies to address these critical terms. Using current knowledge, we recommend an approach to standardize the definitions of the terms antigen and immunogen within the immunology educator community., (Copyright © 2022 The Authors.)

One considers many factors before choosing a career path, such as interest, accessibility of resources, academic ability, and social network support. As employment around the world in science, technology, engineering, and math (STEM) disciplines continues to increase, there is a need to understand why students select specific majors in an effort to increase overall enrollment and retention of STEM majors. The purpose of this study was to elucidate how undergraduate and graduate students were introduced to immunology, a STEM discipline, and how these experiences influenced their desire to pursue immunology as a major. The findings from this study show that a majority of both immunology and nonimmunology majors were initially exposed to immunology through an educational experience compared with a personal experience. Our data also indicate that the timing of the experience is critical, such that an educational experience at an advanced academic level, for example, in college, or a personal experience as a teen or young adult correlated with the decision to pursue an immunology degree. Moreover, graduate students studying immunology report that having research experiences and/or an experience with a mentor positively influenced their decision to pursue immunology. Overall, the findings from this research highlight the type and timing of exposures that influence individuals to major in the field of immunology, and these data can be used in the future to increase the number of immunology graduates., (Copyright © 2021 The Authors.)

Although immunological research has become increasingly important in recent decades for understanding infectious and immune-mediated diseases, immunological pedagogy at the undergraduate level has lagged behind in reports of evidence-based scholarship. To address the need for a renewed emphasis on immunology education and to describe the current status of undergraduate education in immunology, an online survey of instructors with experience in teaching immunology was conducted. The survey investigated the effects of instructors' level of teaching experience, target student population, and course components on the emphasis given to certain immunology subtopics in their courses. Instructor teaching experience and current role in teaching influenced the proportion of time allotted to lab techniques, clinical topics, and evolutionary aspects, but type of institution (undergraduate and graduate degree-granting institutions) did not affect course content or emphasis on subtopics. Topics that received the greatest emphasis were the adaptive immune system, the innate immune system, host-pathogen interactions, and molecular mechanisms. Vaccines, hypersensitivity, autoimmunity, and essential immunology techniques were ranked slightly lower, while topics such as evolution, metabolism and antibody purification received the least emphasis. Inclusion of a lab component increased time given to lab-related and clinical topics but did not affect the perceived importance of various scientific competencies. These data describe current curricular practices of instructors who have experience teaching immunology and inform curricular priorities and course design frameworks for undergraduate immunology education., (©2021 Author(s). Published by the American Society for Microbiology.)

The field of immunology is rapidly evolving and has significant relevance to understanding human health, particularly in light of the threat from infectious diseases and the ability to harness the immune system to treat cancer, autoimmune diseases, and allergies. Providing opportunities to explore the field of immunology is relevant to undergraduate students interested in pursuing careers in health professions and biomedical research. There are calls for greater emphasis on interdisciplinary science education at the undergraduate level and the acquisition of transferrable competencies that will prepare undergraduates for success in a range of careers. The study of immunology provides an ideal platform to expose students to interdisciplinary science, both at the foundational and applied level. We describe the organization of an immunology curriculum, development of program learning objectives, selection and mapping of content objectives across courses, and programmatic assessment with the intent to meet calls for reform in undergraduate biology education., (Copyright © 2020 The Authors.)

Over the last few decades, there has been a shift in the classroom from lecture-based to active learning settings with the argument that students retain more information when they are involved in the learning process. This correlation is even stronger when the active learning setting incorporates a real-world or personal connection. Using active learning activities that develop students' ability to comprehend primary scientific literature is particularly important in the field of immunology, due to the rapid expansion of information in the field, which has been further accelerated due to the COVID-19 pandemic. By nature, immunology is interdisciplinary, requiring an integrated knowledge of concepts from several scientific disciplines to understand complex immune processes. Engaging undergraduate students through the use of primary literature can improve scientific literacy, develop critical thinking, and enhance understanding of complex topics. To explore this, we utilized a group learning activity in an introductory immunology course that incorporated both a coronavirus-related review and COVID-19 clinical research article. We found that this learning activity significantly enhanced student confidence in key scientific literacy skills: reading scientific literature, clearly explaining relevant points, and describing conclusions generated from the data. Moreover, all students reported that they enjoyed the activity and that it helped them understand more about the current COVID-19 pandemic in the context of the immune response., (© 2020 The Authors. Biochemistry and Molecular Biology Education published by Wiley Periodicals LLC on behalf of International Union of Biochemistry and Molecular Biology.)

Interest in using harvest aids (defoliants or crop desiccants) such as paraquat, carfentrazone-ethyl, glyphosate, and sodium chlorate (NaClO 3 ) have become increasingly important to assure harvest efficiency, producer profit, and to maintain seed quality. However, information on the effects of harvest aids on seed nutrition (composition) (protein, oil, fatty acids, sugars, and amino acids) in soybean is very limited. The objective of this research was to investigate the influence of harvest aids on seed protein, oil, fatty acids, sugars, and amino acids in soybean. Our hypothesis was that harvest aid may influence seed nutrition, especially at R6 as at R6 the seeds may still undergo biochemical changes. Field experiments were conducted in 2012 and 2013 under Midsouth USA environmental conditions in which harvest aids were applied at R6 (seed-fill) and R7 (yellow pods) growth stages. Harvest aids applied included an untreated control, 0.28 kg ai ha -1 of paraquat, 0.28 kg ai ha -1 of paraquat, and 1.015 kg ai ha -1 of carfentrazone-ethyl (AIM); 6.72 kg ai ha -1 sodium chlorate, 1.015 kg ai ha -1 carfentrazone-ethyl; and 2.0 kg ae ha -1 glyphosate. Results showed that the application of harvest aids at either R6 or R7 resulted in the alteration of some seed composition such as protein, oil, oleic acid, fructose, and little effects on amino acids. In addition, harvest aids affected seed composition constituents differently depending on year and growth stage. This research demonstrated the possible alteration of some nutrients by harvest aids. This research helps growers and scientists to advance the understanding and management of harvest aids and investigate possible effects of harvest aids on seed nutrition.

Immunology has its developmental roots in understanding protection of the host from pathogens, leading to the development of vaccines and subsequently identification of soluble and cellular components of the immune system. Thus, immunology education has historically been tightly linked to infectious disease. Decades of research have demonstrated that the complexity and intricacies of the immune system are far greater than perhaps was once imagined. As a system that interfaces with all other organ systems in the body, it plays a key role in both maintaining health and causing life-threatening disease, thereby solidifying its importance in several clinical specialties beyond protective immunity. In the past decade, tremendous advances have taken place in which scientists and physicians have begun to harness the power of the immune system to create immunotherapies to fight cancer, inflammatory syndromes and autoimmune diseases. Thus, the argument can be made that training individuals in the field of immunology is becoming increasingly important. However, immunology is a highly conceptual discipline and understanding how the multiple cellular and soluble components of the immune system work in concert requires knowledge in a number of disciplines, including molecular biology, cell biology, genetics, and biochemistry. Time is needed for students to process, evaluate, and apply this information in meaningful ways. Concomitantly, knowledge in the field of immunology is expanding rapidly, bolstering the need for increased time in the curriculum to facilitate the ability of educators to convey information so that it can be effectively understood and applied. We propose that it is time for a renaissance in immunology education at the undergraduate level to better prepare individuals who will subsequently pursue careers in medicine, related health professions, and research. The purpose of this article is to discuss the current state of undergraduate immunology education with respect to its prevalence and how this compares to other biological disciplines, the need to develop robust immunology curricula at the undergraduate level and the importance of such programs in preparing students for pursuing postgraduate training in the health professions, and research-intensive careers., (Copyright © 2019 Bruns, Deaver and Justement.)

Background: Recurrent pharyngotonsillitis due to Streptococcus pyogenes develops regardless of whether infecting strains are resistant or susceptible to first-line antimicrobials. Causation for recurrent infection is associated with the use of first-line antimicrobials that fail to penetrate deep tissue and host cell membranes, enabling intracellular S. pyogenes to survive throughout repeated rounds of antimicrobial therapy., Objective: To determine whether simvastatin, a therapeutic approved for use in the treatment of hypercholesterolemia, and ML141, a first-in-class small molecule inhibitor with specificity for human CDC42, limit host cell invasion by S. pyogenes., Methods: Assays to assess host cell invasion, bactericidal activity, host cell viability, actin depolymerization, and fibronectin binding were performed using the RAW 267.4 macrophage cell line and Human Umbilical Vein Endothelial Cells (HUVEC) infected with S. pyogenes (90-226) and treated with simvastatin, ML141, structural analogs of ML141, or vehicle control., Results: Simvastatin and ML141 decreased intracellular infection by S. pyogenes in a dose-dependent manner. Inhibition by simvastatin persisted following 1 h washout whereas inhibition by ML141 was reversed. During S. pyogenes infection, actin stress fibers depolymerized in vehicle control treated cells, yet remained intact in simvastatin and in ML141 treated cells. Consistent with the previous characterization of ML141, simvastatin decreased host cell binding to fibronectin. Structural analogs of ML141, designated as the RSM series, decreased intracellular infection through non-cytotoxic, nonbactericidal mechanisms., Conclusion: Our findings demonstrate the potential of repurposing simvastatin and of developing CDC42-targeted therapeutics for eradicating intracellular S. pyogenes infection to break the cycle of recurrent infection through a host-directed approach., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Statins are potent modulators of immune responses, resulting in their ability to enhance host survival from primary bacterial infections. Alterations in primary immune responses that may be beneficial for survival following infection may also result in alterations in the generation of the immunologic memory response and subsequently affect immune responses mounted during secondary bacterial infection. In this study, we report that levels of total serum IgG2c, following primary infection, were decreased in simvastatin pretreated mice, and investigate the effect of simvastatin treatment, prior to primary infection, on immune responses activated during secondary S. aureus infection. A secondary infection model was implemented whereby simvastatin pretreated and control mice were reinfected with S. aureus 14 days after primary infection, with no additional simvastatin treatment, and assessed for survival and alterations in immune function. While survivability to secondary S. aureus infection was not different between simvastatin pretreated and control mice, memory B and T lymphocyte functions were altered. Memory B cells, isolated 14 days after secondary infection, from simvastatin pretreated mice and stimulated ex vivo produced increased levels of IgG1 compared to memory B cells isolated from control mice, while levels of IgM and IgG2c remained similar. Furthermore, memory B and T lymphocytes from simvastatin pretreated mice exhibited a decreased proliferative response when stimulated ex vivo compared to memory cells isolated from control mice. These findings demonstrate the ability of a short term, low dose simvastatin treatment to modulate memory immune function.

Corn infected with Ustilago maydis (common smut) produces galls that are valued as a delicacy in some cultures. During a 4-year period, aflatoxin levels in asymptomatic kernels of smutted ears were, on average, 45-fold higher than in kernels harvested from smut-free control ears and 99-fold higher than in smut galls. Aflatoxin levels in smut galls were lower than in kernels of smut-free control corn in all years combined. Fumonisin levels in asymptomatic kernels harvested from smutted ears were 5.2-fold higher than in kernels from smut-free control ears and 4.0-fold higher than in smut galls. Fumonisin levels in smut galls were not significantly different than in kernels of smut-free control corn. These studies indicate that, although corn smut was relatively free of the mycotoxins studied, the asymptomatic kernels of those ears contained mycotoxins at levels much higher than usually considered safe for direct human consumption.

Murine double minute-2 (MDM2), an E3 ligase that regulates the cell cycle and inflammation, is highly expressed in podocytes. In podocyte injury, MDM2 drives podocyte loss by mitotic catastrophe, but the function of MDM2 in resting podocytes has not been explored. Here, we investigated the effects of podocyte MDM2 deletion in vitro and in vivo. In vitro, MDM2 knockdown by siRNA caused increased expression of p53 and podocyte death, which was completely rescued by coknockdown of p53. Apoptosis, pyroptosis, pyronecrosis, necroptosis, ferroptosis, and parthanatos were excluded as modes of occurrence for this p53-overactivation-related cell death (here referred to as podoptosis). Podoptosis was associated with cytoplasmic vacuolization, endoplasmic reticulum stress, and dysregulated autophagy (previously described as paraptosis). MDM2 knockdown caused podocyte loss and proteinuria in a zebrafish model, which was consistent with the phenotype of podocyte-specific MDM2-knockout mice that also showed the aforementioned ultrastructual podocyte abnormalities before and during progressive glomerulosclerosis. The phenotype of both animal models was entirely rescued by codeletion of p53. We conclude that MDM2 maintains homeostasis and long-term survival in podocytes by preventing podoptosis, a p53-regulated form of cell death with unspecific features previously classified as paraptosis., (Copyright © 2015 by the American Society of Nephrology.)

The new Early Soybean Production System (ESPS), developed in the Midsouth USA, including the Mississippi delta, resulted in higher yield under irrigated and non-irrigated conditions. However, information on the effects of the agricultural practices such as row-type (RT: twin- vs. single-row), row-spacing, (RS), seeding rate (SR), soil-type (ST) on seed nutrition under the ESPS environment in the Mississippi delta is very limited. Our previous research in the Mississippi delta showed these agricultural practices altered seed nutrients in one cultivar only. However, whether these effects on seed nutrients will be exhibited by other soybean cultivars with earlier and later maturities across multiple years are not yet known. Therefore, the objective of this research was to evaluate the effects of agricultural practices and cultivar (Cv) differences on seed nutrition in clay and sandy soils under ESPS environment of high heat and drought. Two field experiments were conducted; one experiment was conducted in 2009 and 2010, and the other in 2008, 2009, and 2010 under irrigated conditions. Soybean were grown on 102 cm single-rows and on 25 cm twin-rows with 102 cm centers at seeding rates of 20, 30, 40, and 50 seeds m(-2). Two soybean cultivars (94M80 with earlier maturity; and GP 533 with later maturity) were used. Results showed that increasing seeding rate resulted in increases of protein, sucrose, glucose, raffinose, B, and P concentrations on both single- and twin-rows. However, this increase became either constant or declined at the higher rates (40 and 50 seeds m(-2)). Protein and linolenic acid concentrations were higher in GP 533 than in 94M80 on both row-types, but oil and oleic acid concentrations were in 94M80 than GP 533. Generally, cultivar GP 533 accumulated more seed constituents in seeds than 94M80. In 2010, there were no clear responses of seed nutrients to SR increase in both cultivars, perhaps due to drier year and high heat in 2010. It is concluded that RT and SR can alter seed nutrition under clay and sandy soils, especially under high heat and drought conditions as in the Mississippi delta.

Information on the effects of management practices on soybean seed composition is scarce. Therefore, the objective of this research was to investigate the effects of planting date (PD) and seeding rate (SR) on seed composition (protein, oil, fatty acids, and sugars) and seed minerals (B, P, and Fe) in soybean grown in two row-types (RTs) on the Mississippi Delta region of the Midsouth USA. Two field experiments were conducted in 2009 and 2010 on Sharkey clay and Beulah fine sandy loam soil at Stoneville, MS, USA, under irrigated conditions. Soybean were grown in 102 cm single-rows and 25 cm twin-rows in 102 cm centers at SRs of 20, 30, 40, and 50 seeds m(-2). The results showed that in May and June planting, protein, glucose, P, and B concentrations increased with increased SR, but at the highest SRs (40 and 50 seeds m(-2)), the concentrations remained constant or declined. Palmitic, stearic, and linoleic acid concentrations were the least responsive to SR increases. Early planting resulted in higher oil, oleic acid, sucrose, B, and P on both single and twin-rows. Late planting resulted in higher protein and linolenic acid, but lower oleic acid and oil concentrations. The changes in seed constituents could be due to changes in environmental factors (drought and temperature), and nutrient accumulation in seeds and leaves. The increase of stachyose sugar in 2010 may be due to a drier year and high temperature in 2010 compared to 2009; suggesting the possible role of stachyose as an environmental stress compound. Our research demonstrated that PD, SR, and RT altered some seed constituents, but the level of alteration in each year dependent on environmental factors such as drought and temperature. This information benefits growers and breeders for considering agronomic practices to select for soybean seed nutritional qualities under drought and high heat conditions.

Oral tolerance is dependent on the complex architecture of the mucosal system of the gastrointestinal tract, its associated lymphoid tissue, and specialized immune cells. Changes in this architecture or the failure of any of its components may hinder the generation of oral tolerance. The larynx and esophagus are the gateway to the gastrointestinal tract, serving as the site of oral antigen introduction to the immune system and may have an important role in establishing tolerance. Intragastric gavage is a common method for precise oral dosing of rodents, particularly in studies examining oral tolerance. However, complications such as esophageal trauma can occur and induce complicating factors that affect experimental outcomes. In this study, we examined the esophageal epithelium for alterations resulting from long-term repeated daily use of intragrastric gavage and its effect on the induction of tolerance. Tolerance to ovalbumin could not be achieved after using intragastric gavage for 14 d or more consecutively to introduce ovalbumin. However, tolerance was achieved when intragastric gavage was used for shorter durations. After 14 d of gavage, disruption of the esophageal mucosal epithelium indicative of an inflammatory pathology, cellular influx into the esophageal tissue, and proinflammatory cytokines in the tissue were absent, and the CD3(+) cell population in the esophageal epithelium decreased. These findings provide initial evidence for the important roles of esophageal integrity and cellular populations in the induction of oral tolerance and suggest possible immunologic sequelae in experiments involving the use of extended, repeated gavage.

Th17 cells are critical for the clearance of extracellular bacteria and fungi, but also contribute to the pathology of autoimmune diseases and allergic inflammation. After exposure to an appropriate cytokine environment, Th17 cells can acquire a Th1-like phenotype, but less is known about their ability to adopt Th2 and Th9 effector programs. To explore this in more detail, we used an IL-17F lineage tracer mouse strain that allows tracking of cells that formerly expressed IL-17F. In vitro-derived Th17 cells adopted signature cytokine and transcription factor expression when cultured under Th1-, Th2-, or Th9-polarizing conditions. In contrast, using two models of allergic airway disease, Th17 cells from the lungs of diseased mice did not adopt Th1, Th2, or Th9 effector programs, but remained stable IL-17 secretors. Although in vitro-derived Th17 cells expressed IL-4Rα, those induced in vivo during allergic airway disease did not, possibly rendering them unresponsive to IL-4-induced signals. However, in vitro-derived, Ag-specific Th17 cells transferred in vivo to OVA and aluminum hydroxide-sensitized mice also maintained IL-17 secretion and did not produce alternative cytokines upon subsequent OVA challenge. Thus, although Th17 cells can adopt new phenotypes in response to some inflammatory environments, our data suggest that in allergic inflammation, Th17 cells are comparatively stable and retain the potential to produce IL-17. This might reflect a cytokine environment that promotes Th17 stability, and allow a broader immune response at tissue barriers that are susceptible to allergic inflammation., (Copyright © 2014 by The American Association of Immunologists, Inc.)

Staphylococcus aureus is a leading causative agent in sepsis, endocarditis, and pneumonia. An emerging concept is that prognosis worsens when the infecting S. aureus strain has the capacity to not only colonize tissue as an extracellular pathogen, but to invade host cells and establish intracellular bacterial populations. In previous work, we identified host CDC42 as a central regulator of endothelial cell invasion by S. aureus. In the current work, we report that ML 141, a first-in-class CDC42 inhibitor, decreases invasion and resultant pathogenesis in a dose-dependent and reversible manner. Inhibition was found to be due in part to decreased remodeling of actin that potentially drives endocytic uptake of bacteria/fibronectin/integrin complexes. ML 141 decreased binding to fibronectin at these complexes, thereby limiting a key pathogenic mechanism used by S. aureus to invade. Structural analogs of ML 141 were synthesized (designated as the RSM series) and a subset identified that inhibit invasion through non-cytotoxic and non-bactericidal mechanisms. Our results support the development of adjunctive therapeutics targeting host CDC42 for mitigating invasive infection at the level of the host.

Mycotoxin contamination levels in maize kernels are controlled by a complex set of factors including insect pressure, fungal inoculum potential, and environmental conditions that are difficult to predict. Methods are becoming available to control mycotoxin-producing fungi in preharvest crops, including Bt expression, biocontrol, and host plant resistance. Initial reports in the United States and other countries have associated Bt expression with reduced fumonisin, deoxynivalenol, and zearalenone contamination and, to a lesser extent, reduced aflatoxin contamination in harvested maize kernels. However, subsequent field results have been inconsistent, confirming that fumonisin contamination can be reduced by Bt expression, but the effect on aflatoxin is, at present, inconclusive. New maize hybrids have been introduced with increased spectra of insect control and higher levels of Bt expression that may provide important tools for mycotoxin reduction and increased yield due to reduced insect feeding, particularly if used together with biocontrol and host plant resistance.

During severe sepsis, microvesicles that are positive for tissue factor (TF) are at increased levels within blood and in pulmonary lavage. These microvesicles potentially disperse TF, the major initiator of the coagulation cascade, throughout multiple organ systems, initiating fibrin deposition and resultant ischemia. The source of these microvesicles has remained incompletely defined. Although TF(+) microvesicles are shed from cells that express nascent TF transcript in response to injury, recent findings revealed that circulating, full-length TF protein is detectable prior to these nascent transcripts. This finding suggested that the protein is released from constitutive sources as an acute response. We examined whether Staphylococcus aureus, the Gram-positive bacteria that is emerging as one of the most common etiologic agents in sepsis, is capable of stimulating the release of TF(+) microvesicles from a pulmonary cell line that constitutively expresses TF protein. We found that host cell invasion stimulated an acute release of TF(+) microvesicles and that these microvesicles mediated the transfer of the protein to TF-negative endothelial cells. We also found that transfer was inhibited by cholesterol-lowering simvastatin. Taken together, our findings reveal that S. aureus pathogenesis extends to the acute release of TF(+) microvesicles and that inhibiting dispersal by this mechanism may provide a therapeutic target., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Staphylococcus aureus is the most prevalent etiologic agent of sepsis. Statins, primarily prescribed for their cholesterol-lowering capabilities, may be beneficial for treating sepsis due to their anti-inflammatory properties. This study examined the effect of low dose, short term simvastatin pretreatment in conjunction with antibiotic treatment on host survival and demonstrated that pretreatment with simvastatin increased survival of C57BL/6 mice in response to S. aureus infection. In vitro studies revealed that short term simvastatin pretreatment did not reduce S. aureus-stimulated expression of surface proteins necessary for macrophage presentation of antigen to T cells, such as MHC Class II and costimulatory molecules CD80 and CD86, but did reduce both basal and S. aureus-stimulated levels of C5aR. Additionally, this work demonstrated the ability of simvastatin to dampen macrophage responses initiated not only by bacteria directly but by membrane vesicles shed in response to infection, revealing a new mechanism of immune modulation by statins. These data demonstrate the ability of short term simvastatin pretreatment to modulate immune responses and identify new insights into the underlying mechanisms of the anti-inflammatory properties of simvastatin that may decrease the pathophysiological effects leading to sepsis.

The mucosal immune system is constantly exposed to antigen, whether it be food antigen, commensal bacteria, or harmful antigen. It is essential that the mucosal immune system can distinguish between harmful and non-harmful antigens, and initiate an active immune response to clear the harmful antigens, while initiating a suppressive immune response (tolerance) to non-harmful antigens. Oral tolerance is an immunologic hyporesponsiveness to an orally administered antigen and is important in preventing unnecessary gastrointestinal tract inflammation, which can result in a number of autoimmune and hypersensitivity diseases. Probiotics (beneficial intestinal bacteria), T regulatory cells, and dendritic cells (DCs) are all essential for generating tolerance. Antibiotics are commonly prescribed to fight infections and often necessary for maintaining health, but they can disrupt the normal intestinal probiotic populations. There is increasing epidemiologic evidence that suggests that antibiotic usage correlates with the development of atopic or irritable bowel disorders, which often result due to a breakdown in immune tolerance. This study investigated the effect of the antibiotic erythromycin on oral tolerance induction to ovalbumin. The results demonstrated that antibiotic treatment prior to exposure to fed antigen prevents tolerance to that antigen, which may be associated with a reduction in intestinal Lactobacillus populations. Furthermore, antibiotic treatment resulted in a significant decrease in the tolerogenic CD11c(+)/CD11b(+)/CD8α(-) mesenteric lymph node DCs independent of tolerizing treatment. These results provide evidence that antibiotic treatment, potentially through its effects on tolerogenic DCs and intestinal microflora, may contribute to autoimmune and atopic disorders via a breakdown in tolerance and support prior epidemiologic studies correlating increased antibiotic usage with the development of these disorders.

The development of allergic inflammation requires the orchestration of gene expression from the inflamed tissue and from the infiltrating immune cells. Since many of the cytokines that promote allergic inflammation signal through hematopoietin family receptors, the Signal Transducer and Activator of Transcription (STAT) family have obligate roles in pro-allergic cytokine-induced gene regulation in multiple cell types. In this review, we summarize work defining the contribution of each of the STAT family members to the development of allergic inflammation, using data from mouse models of allergic inflammation, studies on patient samples and correlations with single nucleotide polymorphisms in STAT genes.

Stat6 is a transcription factor that regulates important cellular processes such as proliferation, differentiation, and survival through mediating IL-4 and IL-13 signaling. Importantly, increasing evidence indicates of a role for Stat6 in lymphoproliferative disorders. Mice expressing a constitutively active form of Stat6 (Stat6VT) primarily in T lymphocytes were generated, and it has been recently described that a small percentage (approximately 5%) of these mice develop a spontaneous lymphoproliferative disorder (LPD) resulting in dramatic splenomegaly and altered splenic cell populations. Here, we report that Stat6VT mice housed in a non-pathogen-free environment have an increased incidence (37%) of the LPD. Additionally, examination of the expression of Stat6-regulated genes known to have roles in tumorigenesis demonstrated that there appears to be no one genetic alteration common to lymphocytes from Stat6VT/LPD mice. Interestingly, however, uniform exposure to antigen via immunization resulted in complete abrogation of the LPD in Stat6VT mice., (Copyright 2009 Elsevier GmbH. All rights reserved.)

Beta1-containing adhesions at the plasma membrane function as dynamic complexes to provide bidirectional communication between the cell and its environment, yet commonly are used by pathogens to gain host cell entry. Recently, the cholesterol-lowering drug simvastatin was found to inhibit host invasion through beta1-containing adhesion complexes. To better understand the regulatory mechanisms controlling adhesion formation and uptake and the use of these complexes by Staphylococcus aureus, the primary etiologic agent in sepsis, bacteremia and endocarditis, we investigated the mechanism of inhibition by simvastatin. In response to simvastatin, adhesion complexes diminished as well as beta1 trafficking to the plasma membrane required to initiate adhesion formation. Simvastatin stimulated CDC42 activation and coupling to p85, a small-guanosine triphosphatase (GTPase) activating protein (GAP), yet sequestered CDC42 coupled to p85 within the cytosol. Loss of p85 GAP activity through use of genetic strategies decreased host cell invasion as well as beta1 trafficking. From these findings, we propose a mechanism whereby p85 GAP activity localized within membrane compartments facilitates beta1 trafficking. By sequestering p85 within the cytosol, simvastatin restricts the availability and uptake of the receptor used by pathogenic strains to gain host cell entry., (Copyright 2009 Elsevier Inc. All rights reserved.)

Mycotoxin and Aspergillus flavus levels in soil-surface corn debris left by no-till agriculture methods (stover, cobs, and cobs with grain) were determined during the December-March fallow period for near-isogenic Bt and non-Bt hybrid corn. By December, average mycotoxin levels in non-Bt corn were many times higher in cobs with grain than in grain harvested in September (total aflatoxins, 774 vs 211 ng/g; total fumonisins, 216 vs 3.5 microg/g; cyclopiazonic acid, 4102 vs 72.2 microg/g; zearalenone, 0.2 vs < 0.1 microg/g). No trichothecenes were detected. Levels of mycotoxins and A. flavus propagules were approximately 10- to 50-fold lower in cobs without grain and stover, respectively, for all mycotoxins except zearalenone. Mycotoxin levels in corn debris fractions decreased during winter but began to rise in March. Levels of all mycotoxins and A. flavus propagules were lower in harvested grain and debris from Bt than non-Bt corn, but differences were significant (p < 0.05) only for aflatoxins.

IL-4 is required for the pathogenesis of atopic diseases and immune regulation. Stat6 is critical for IL-4-induced gene expression and Th cell differentiation. Recently, we have generated mice expressing a mutant Stat6 (Stat6VT) under control of the CD2 locus control region that is transcriptionally active independent of IL-4 stimulation. To determine whether active Stat6 in T cells is sufficient to alter immune regulation in vivo, we mated Stat6VT transgenic mice to IL-4-deficient mice. Stat6VT expression in IL-4-deficient lymphocytes was sufficient to alter lymphocyte homeostasis and promote Th2 differentiation in vitro. HyperTh2 levels in Stat6 transgenic mice correlated with an atopic phenotype that manifested as blepharitis and pulmonary inflammation with a high level of eosinophilic infiltration. In the absence of endogenous IL-4, Stat6VT transgenic mice were protected from allergic inflammation. Thus, in mice with hyperTh2 immune responses in vivo, IL-4 is a critical effector cytokine.

Signal transducer and activator of transcription 6 (STAT6) is critical for IL-4 and IL-13 responses, and necessary for the normal development of Th2 cells. We previously generated mice that express a constitutively active STAT6 (STAT6VT) under control of the CD2 locus control region, which directs expression to the T-cell compartment. We now describe that a small proportion of these mice (~5%) develop a spontaneous lymphoproliferative disease (LPD) that results in dramatic splenomegaly. The cell populations observed in the LPD spleens can be divided into 2 categories, those that are composed of mixed lineage cells and those that are predominantly T cells with a phenotype similar to that in autoimmune lymphoproliferative syndrome (ALPS) patients. These data suggest that while active STAT6 is not a transforming factor, expression in T cells predisposes toward the development of lymphoproliferative disorders.

IL-4 is a critical cytokine in the regulation of immune responses. In B lymphocytes, IL-4 signaling promotes the Stat6-dependent cell surface expression of several proteins including MHC Class II and CD86. However, the requirement for other transcription factors in IL-4-induced B cell gene expression has not been studied extensively. Here, we show that IL-4 induces NF-kappaB p100 processing to NF-kappaB p52 in B cells but not in T cells or macrophages. IL-4 induced NF-kappaB p52 production requires PI-3K activity and correlates with IkappaB kinase phosphorylation and TNF receptor-associated factor 3 degradation. Blocking NF-kappaB activity eliminates IL-4-stimulated gene expression in B cells by reducing IL-4-induced DNA binding but not phosphorylation or nuclear localization of Stat6. These results describe a novel role for NF-kappaB in IL-4-induced signaling and gene expression.

Signal transducers and activators of transcription (STAT) are a family of transcription factors that regulate a broad range of cellular processes, such as proliferation, differentiation, and survival, in a large variety of cell types. Because of their regulation of diverse cellular functions, their aberrant activation is frequently associated with disease development, particularly oncogenic diseases. Much evidence exists to suggest that STAT proteins play a significant role in cellular transformation. However, which STAT proteins and to what extent they cause transformation and subsequent disease progression are topics currently being investigated. In this review, we will report on the findings concerning the involvement of Stat6 in the development of lymphoma and leukemia. Mounting evidence, in both patients and mouse models, supports a model where Stat6 is not a mere bystander, but rather, plays an active role in promoting a transformed phenotype.

Primary T helper 2 cells are heterogeneous, expressing subsets of cytokines at varying levels. Mechanisms controlling this spectrum of phenotypes are still unclear. The ETS family transcription factor PU.1 is expressed in Th2 but not Th1 cells. Th2 cytokine production is decreased in cultures transduced with a PU.1-expressing retrovirus and increased in Th2 cells following RNAi that decreases PU.1 expression. In primary cultures, PU.1 expression is restricted to a subpopulation of Th2 cells that express CCL22 and a subset of Th2 cytokines. PU.1 regulates the Th2 phenotype by interfering with GATA-3 DNA binding without altering GATA-3 protein levels. Thus, the expression of PU.1 in subsets of Th2 cells establishes a defined cytokine profile and contributes towards establishing the spectrum of cytokine production observed in Th2 populations.

IL-4 is a critical cytokine in the regulation of immune responses and genesis of atopy. Engagement of the IL-4R activates multiple signaling pathways, including the transcription factor Stat6. Stat6-deficient mice demonstrate the importance of this factor in lymphocyte proliferation, gene expression, and Th cell differentiation. Recently, a mutant Stat6 (Stat6VT) was generated that is transcriptionally active independent of IL-4 stimulation. To determine the ability of a constitutively active Stat6 to mimic IL-4-stimulated responses, we have generated transgenic mice expressing Stat6VT under control of the CD2 locus control region, restricting expression to lymphoid populations. The phenotype of Stat6VT transgenic mice is similar, but not identical, to IL-4 transgenic mice, suggesting a critical role for Stat6-independent signaling pathways in the generation of some IL-4 responses in vivo. The expression of a constitutively active Stat6 in vivo increases surface expression of IL-4-induced genes and increases serum levels of IgG1 and IgE, compared with nontransgenic mice. Stat6VT expression increases Th2 differentiation in vivo and in vitro. Stat6VT expression also dramatically alters homeostasis of peripheral lymphocyte populations resulting in decreased CD3(+) cells and increased B220(+) cells, compared with nontransgenic littermates. Altered T and B cell populations correlate with an activated phenotype and increased cell death in transgenic T cell, but not B cell, populations. Together these results suggest that expression of a constitutively active Stat6 has distinct effects on B and T lymphocytes.

Regulation of hematopoietic progenitor cell homeostasis is crucial for maintenance of innate immunity and the ability of the body to respond to injury and infection. In this report, we demonstrate that progenitor cell numbers and cycling status in vivo are dramatically increased in mice deficient in Stat6 and decreased in mice deficient in Stat4, targeted mutations which also alter T helper cell polarization. Experiments using mice that have T cell restricted transgenic expression of Stat4 or Stat6 or have been in vivo depleted of T cell subsets demonstrate that CD4(+) T cells regulate progenitor cell activity. Injection of the Th1 cytokine Oncostatin M but not other cytokines into Stat4-deficient mice recovers progenitor cell activity to wild-type levels. Thus, T helper cells actively regulate hematopoietic progenitor cell homeostasis.

Stat4 is activated in response to IL-12. Most functions of IL-12, including the induction of IFN-gamma, are compromised in the absence of Stat4. Since the precise role of Stat4 in IFN-gamma induction has not been established, experiments were conducted to examine Stat4 activation of IFN-gamma and other genes required for cytokine-induced expression of IFN-gamma. We first examined IL-12 signaling components. Basal expression of IL-12Rss1 and IL-12Rss2 is decreased in Stat4-deficient cells compared with that in control cells. However, IL-12 was still capable of inducing equivalent phosphorylation of Jak2 and Tyk2 in wild-type and Stat4-deficient activated T cells. We have further determined that other cytokine signaling pathways that induce IFN-gamma production are defective in the absence of Stat4. IL-18 induces minimal IFN-gamma production from Stat4-deficient activated T cells compared with control cells. This is due to defective IL-18 signaling, which results from the lack of IL-12-induced, and Stat4-dependent, expression of the IL-18R. Following IL-12 pretreatment to induce IL-18R, wild-type, but not Stat4-deficient, activated T cells demonstrated IL-18-induced NF-kappaB DNA-binding activity. In addition, IL-12-pretreated Stat4-deficient activated T cells have minimal IFN-gamma production followed by stimulation with IL-18 alone or in combination with IL-12 compared with control cells. Thus, Stat4 activation by IL-12 is required for the function of multiple cytokine pathways that result in induction of IFN-gamma.