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Main Congress
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It’s very exciting to have this many notable speakers and experts available in relatively small settings so you can ask them questions and engage them. It really is terrific. I’ve been impressed by the number of different kinds of topic and areas of exploration, and the level of expertise represented here.
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~ Prof Lesley Curtis
Interim Executive Director, Duke Clinical Research Institute, Duke University Medical Centre
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Programme >
Emerging Infectious Disease Plenary
Short Talks
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Track type:
Plenary
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Date: 18 Sep 2021
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Time: 1200 - 1245
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Location: Seminar Room 4
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TOPIC 1:
SARS-CoV-2-specific T cells in Infection and Vaccination: A Case for their Protective Role
Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2), the virus causing Coronavirus Diseases 2019 (COVID-19), triggers an adaptive immunity that results in the production of virus-specific antibodies and T cells. This symposium will present an overview on studies of SARS-CoV-2-specific T cells, all pointing towards their protective role.
Longitudinal analysis of virological and immunological parameters in 12 patients with symptomatic acute SARS-CoV-2 infection from disease onset to convalescence or death showed that early appearance, multi-specificity and functionality of virus-specific T cells are associated with accelerated viral clearance and with protection from severe COVID-19.
In addition, analysis of SARS-CoV-2–specific T cells in individuals who clear infection without symptoms showed an increased IFN-γ and IL-2 production compared to virus-specific T cells in symptomatic patients. This was associated with a proportional secretion of IL-10 and proinflammatory cytokines (IL-6, TNF-α, and IL-1β) only in asymptomatic infection. Thus, asymptomatic SARS-CoV-2–infected individuals mount a highly functional virus-specific cellular immune response.
Moreover, multiple sequential serological and T cell analysis following the first dose of Pfizer/BioNTech BNT162b2 vaccine detected Spike-specific T cells and binding antibodies after 10 days, while receptor-blocking and SARS-CoV-2 neutralising antibodies were mostly undetectable at this early time-point. This early induction correlates with the onset of protection against COVID-19 in vaccinated individuals.
TOPIC 2:
Human Fetal Immunity and Microbial Priming
The human fetal immune system is known to develop early during gestation with significant diversity in its immune repertoire. However, the factors responsible for such in-utero priming of the immune system remain elusive. Recent studies have reported microbe traces in human placenta and fetal samples. To better understand its implications in priming and activation of memory T cells identified during fetal development, microbes are profiled across multiple fetal organs using 16S rRNA gene sequencing approach and detected a low but consistent microbial signal in 2nd trimester of gestation. Several live bacterial strains were isolated and identified by aerobic and anaerobic culturing of fetal tissues, that induced memory T cell activation and expansion of fetal lymph node T cells, thereby suggesting priming of fetal immune system with bacterial antigens.
Notably, through state-of-art imaging techniques will visually show the spatial localisation of bacteria in developing fetal gut lumen at 14 week EGA. These findings have broader implications for the understanding of human development and the establishment of immune competency and diversity before birth.
TOPIC 3:
Systemic Mast Cell Activation is Associated with Vascular Pathologies in a Non-human Primate Model of Ebola Virus Disease
Ebola virus (EBOV) is a human pathogen responsible for high morbidity and mortality in infected individuals. It causes Ebola haemorrhagic fever disease (EVD), which is characterised in its severe form by abnormal coagulopathies resulting in plasma loss and vascular leakage. Mast cells are tissue resident immune cells that have well defined role in the regulation of vascular homeostasis and the coagulation cascade. Using a non-human primate (NHP) model of EVD we report widespread activation of mast cells in multiple tissues of EBOV infected animals and that areas of mast cell activation coincide with vascular leakage and haemorrhagic manifestations.
Furthermore, serum levels of the mast cell-specific biomarker, chymase, were significantly increased during EBOV infection of NHPs and were inversely correlated with serum albumin levels, which can be an indicator of vascular leakage. These data support that there is systemic activation of mast cells in the NHP model of EVD and suggests an association of MC activation with vascular leakage.
*Information is correct at time of update
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