PRIMING AND MAINTENANCE OF MYCOBACTERIUM TUBERCULOSIS SPECIFIC T CELL RESPONSES

Mycobacterium tuberculosis is the leading cause of death due to a single infectious agent worldwide. Immune response elicited against the bacterium is sufficient to control, but not to eliminate the pathogen leading to the establishment of asymptomatic state called latency. Currently very little is known about conditions that are required to prime robust, protective immune response in the initial stages of infection. We hypothesized that CD40 ligation is essential for the priming of strong Th1 response and for the subsequent control of M. tuberculosis infection. Furthermore, it is unknown how persistent exposure to mycobacterial antigens affects the functionality of T cells. Our initial thought was that the reason why immune response cannot eliminate M. tuberculosis and why reactivation occurs is due to T cell exhaustion as a result of continuous antigenic stimulation. Since the goal of every vaccine strategy is to elicit long-lasting and protective immunity, it is necessary to define the factors required for the development and maintenance of effector and memory T cell responses. We hypothesized that CD4 help and IL-15 are required for the development of functional CD8+ memory responses. Our results indicate that in murine model of tuberculosis CD40 ligation on antigen presenting cells either by host- or mycobacterium-derived ligands, is essential for the induction of robust IFN-ƒ× T cell response resulting in protection against disease and death. Once a strong immune response is elicited, long-term control of M. tuberculosis infection is mediated by dynamic changes in the frequency and types of T cell effector functions. We identified that IL-15 was not essential for the proliferation of CD4+ and CD8+ T cells or for the maintenance of their effector functions after primary and secondary M. tuberculosis infection. Our findings indicate that CD4 help was required during priming of effector CD8+ T cells and during secondary infection for the functional and durable memory CD8+ T cell responses. Collectively, the findings presented in this thesis broadened our understanding of what factors are essential for the generation and maintenance of functional effector and recall responses following M. tuberculosis infection

The Role of Attachment in Language Brokering and Psychological Well-being among College Students

Emerging adult (EA), college students from immigrant families continue engaging in language brokering (LB), translating documents and other media for their parents, in ways that can affect their well-being. For these language brokers, the relationship between parental attachment and psychological well-being may be through frequency and perceptions of their LB work. In this study, 459 language brokers (Mage = 21.36, Female = 80%) completed an online questionnaire about frequency and perceptions of LB, attachment, and psychological well-being. Attachment anxiety and avoidance had negative indirect effects on anxiety and somatic symptoms through feelings of LB burden. Attachment anxiety had a negative indirect effect on somatic symptoms through LB intrusiveness. There were negative indirect effects of LB burden on attachment avoidance to anxiety and somatic symptoms. There was a negative indirect effect of LB intrusiveness on attachment avoidance to somatic symptoms. Findings indicate that perceptions of LB may relate to psychological well-being when attachment is insecure

Caregiver Participation Engagement in Child Mental Health Prevention Programs: a Systematic Review

Prevention programs are a key method to reduce the prevalence and impact of mental health disorders in childhood and adolescence. Caregiver participation engagement (CPE), which includes caregiver participation in sessions as well as follow-through with homework plans, is theorized to be an important component in the effectiveness of these programs. This systematic review aims to (1) describe the terms used to operationalize CPE and the measurement of CPE in prevention programs, (2) identify factors associated with CPE, (3) examine associations between CPE and outcomes, and (4) explore the effects of strategies used to enhance CPE. Thirty-nine articles representing 27 unique projects were reviewed. Articles were included if they examined CPE in a program that focused to some extent on preventing child mental health disorders. There was heterogeneity in both the terms used to describe CPE and the measurement of CPE. The majority of projects focused on assessment of caregiver home practice. There were no clear findings regarding determinants of CPE. With regard to the impact of CPE on program outcomes, higher levels of CPE predicted greater improvements in child and caregiver outcomes, as well as caregiver-child relationship quality. Finally, a small number of studies found that motivational and behavioral strategies (e.g., reinforcement, appointment reminders) were successful in promoting CPE. This review highlights the importance of considering CPE when developing, testing, and implementing prevention programs for child mental health disorders. Increased uniformity is needed in the measurement of CPE to facilitate a better understanding of determinants of CPE. In addition, the field would benefit from further evaluating strategies to increase CPE as a method of increasing the potency of prevention programs

Crystal structure of the DNA binding domain of the transcription factor T-bet suggests simultaneous recognition of distant genome sites

The transcription factor T-bet (Tbox protein expressed in T cells) is one of the master regulators of both the innate and adaptive immune responses. It plays a central role in T-cell lineage commitment, where it controls the T[subscript H]1 response, and in gene regulation in plasma B-cells and dendritic cells. T-bet is a member of the Tbox family of transcription factors; however, T-bet coordinately regulates the expression of many more genes than other Tbox proteins. A central unresolved question is how T-bet is able to simultaneously recognize distant Tbox binding sites, which may be located thousands of base pairs away. We have determined the crystal structure of the Tbox DNA binding domain (DBD) of T-bet in complex with a palindromic DNA. The structure shows a quaternary structure in which the T-bet dimer has its DNA binding regions splayed far apart, making it impossible for a single dimer to bind both sites of the DNA palindrome. In contrast to most other Tbox proteins, a single T-bet DBD dimer binds simultaneously to identical half-sites on two independent DNA. A fluorescence-based assay confirms that T-bet dimers are able to bring two independent DNA molecules into close juxtaposition. Furthermore, chromosome conformation capture assays confirm that T-bet functions in the direct formation of chromatin loops in vitro and in vivo. The data are consistent with a looping/synapsing model for transcriptional regulation by T-bet in which a single dimer of the transcription factor can recognize and coalesce distinct genetic elements, either a promoter plus a distant regulatory element, or promoters on two different genes.United States. National Institutes of Health (P01-AI056296

Crystal structure of the DNA binding domain of the transcription factor T-bet suggests simultaneous recognition of distant genome sites

The transcription factor T-bet (Tbox protein expressed in T cells) is one of the master regulators of both the innate and adaptive immune responses. It plays a central role in T-cell lineage commitment, where it controls the TH1 response, and in gene regulation in plasma B-cells and dendritic cells. T-bet is a member of the Tbox family of transcription factors; however, T-bet coordinately regulates the expression of many more genes than other Tbox proteins. A central unresolved question is how T-bet is able to simultaneously recognize distant Tbox binding sites, which may be located thousands of base pairs away. We have determined the crystal structure of the Tbox DNA binding domain (DBD) of T-bet in complex with a palindromic DNA. The structure shows a quaternary structure in which the T-bet dimer has its DNA binding regions splayed far apart, making it impossible for a single dimer to bind both sites of the DNA palindrome. In contrast to most other Tbox proteins, a single T-bet DBD dimer binds simultaneously to identical half-sites on two independent DNA. A fluorescence-based assay confirms that T-bet dimers are able to bring two independent DNA molecules into close juxtaposition. Furthermore, chromosome conformation capture assays confirm that T-bet functions in the direct formation of chromatin loops in vitro and in vivo. The data are consistent with a looping/synapsing model for transcriptional regulation by T-bet in which a single dimer of the transcription factor can recognize and coalesce distinct genetic elements, either a promoter plus a distant regulatory element, or promoters on two different genes

Aberrant CD8+T cells drive reproductive dysfunction in female mice with elevated IFN-γ levels

IntroductionInterferon-gamma (IFN-γ) is pivotal in orchestrating immune responses during healthy pregnancy. However, its dysregulation, often due to autoimmunity, infections, or chronic inflammatory conditions, is implicated in adverse reproductive outcomes such as pregnancy failure or infertility. Additionally, the underlying immunological mechanisms remain elusive.MethodsHere, we explore the impact of systemic IFN-γ elevation on cytotoxic T cell responses in female reproduction utilizing a systemic lupus-prone mouse model with impaired IFN-γ degradation.ResultsOur findings reveal that heightened IFN-γ levels triggered the infiltration of CD8+T cells in the pituitary gland and female reproductive tract (FRT), resulting in prolactin deficiency and subsequent infertility. Furthermore, we demonstrate that chronic IFN-γ elevation increases effector memory CD8+T cells in the murine ovary and uterus.DiscussionThese insights broaden our understanding of the role of elevated IFN-γ in female reproductive dysfunction and suggest CD8+T cells as potential immunotherapeutic targets in female reproductive disorders associated with chronic systemic IFN-γ elevation

A global experiment on motivating social distancing during the COVID-19 pandemic

Finding communication strategies that effectively motivate social distancing continues to be a global public health priority during the COVID-19 pandemic. This cross-country, preregistered experiment (n = 25,718 from 89 countries) tested hypotheses concerning generalizable positive and negative outcomes of social distancing messages that promoted personal agency and reflective choices (i.e., an autonomy-supportive message) or were restrictive and shaming (i.e., a controlling message) compared with no message at all. Results partially supported experimental hypotheses in that the controlling message increased controlled motivation (a poorly internalized form of motivation relying on shame, guilt, and fear of social consequences) relative to no message. On the other hand, the autonomy-supportive message lowered feelings of defiance compared with the controlling message, but the controlling message did not differ from receiving no message at all. Unexpectedly, messages did not influence autonomous motivation (a highly internalized form of motivation relying on one’s core values) or behavioral intentions. Results supported hypothesized associations between people’s existing autonomous and controlled motivations and self-reported behavioral intentions to engage in social distancing. Controlled motivation was associated with more defiance and less long-term behavioral intention to engage in social distancing, whereas autonomous motivation was associated with less defiance and more short- and long-term intentions to social distance. Overall, this work highlights the potential harm of using shaming and pressuring language in public health communication, with implications for the current and future global health challenges

A global experiment on motivating social distancing during the COVID-19 pandemic

Finding communication strategies that effectively motivate social distancing continues to be a global public health priority during the COVID-19 pandemic. This cross-country, preregistered experiment (n = 25,718 from 89 countries) tested hypotheses concerning generalizable positive and negative outcomes of social distancing messages that promoted personal agency and reflective choices (i.e., an autonomy-supportive message) or were restrictive and shaming (i.e. a controlling message) compared to no message at all. Results partially supported experimental hypotheses in that the controlling message increased controlled motivation (a poorly-internalized form of motivation relying on shame, guilt, and fear of social consequences) relative to no message. On the other hand, the autonomy-supportive message lowered feelings of defiance compared to the controlling message, but the controlling message did not differ from receiving no message at all. Unexpectedly, messages did not influence autonomous motivation (a highly-internalized form of motivation relying on one’s core values) or behavioral intentions. Results supported hypothesized associations between people’s existing autonomous and controlled motivations and self-reported behavioral intentions to engage in social distancing: Controlled motivation was associated with more defiance and less long-term behavioral intentions to engage in social distancing, whereas autonomous motivation was associated with less defiance and more short- and long-term intentions to social distance. Overall, this work highlights the potential harm of using shaming and pressuring language in public health communication, with implications for the current and future global health challenges

A multi-country test of brief reappraisal interventions on emotions during the COVID-19 pandemic.

The COVID-19 pandemic has increased negative emotions and decreased positive emotions globally. Left unchecked, these emotional changes might have a wide array of adverse impacts. To reduce negative emotions and increase positive emotions, we tested the effectiveness of reappraisal, an emotion-regulation strategy that modifies how one thinks about a situation. Participants from 87 countries and regions (n = 21,644) were randomly assigned to one of two brief reappraisal interventions (reconstrual or repurposing) or one of two control conditions (active or passive). Results revealed that both reappraisal interventions (vesus both control conditions) consistently reduced negative emotions and increased positive emotions across different measures. Reconstrual and repurposing interventions had similar effects. Importantly, planned exploratory analyses indicated that reappraisal interventions did not reduce intentions to practice preventive health behaviours. The findings demonstrate the viability of creating scalable, low-cost interventions for use around the world