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Dr
Gyaviira Nkurunungi

Uganda

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Project Title

How does exposure to helminths alter vaccine responses: employing cytometry by time-of-flight (CyToF) technology for high-resolution immunophenotyping of cellular pathways underpinning helminth-induced immunomodulation

Project Objectives

Vaccines are a key public health tool but immune responses to several licensed and investigational vaccines are impaired in tropical low-income countries (LICs) compared to temperate high-income countries and in rural, compared to urban, LIC settings. Drivers of these population differences have not been determined. Pre-immunisation immunological profile impacts vaccine responses; however, factors influencing this profile in the tropics are poorly understood. The proposed work addresses the hypothesis that repeated exposure to chronic parasitic infections modulates the host pre-immunisation immunological response, consequently impairing vaccine-specific responses.

Host Organisation

Department Institution Country
Uganda National Health Research Organisation (UNHRO) Uganda National Health Research Organisation (UNHRO) UG

EDCTP Project

TMA2019PF-2707

EDCTP Program

EDCTP2

EDCTP Project Call

EDCTP-AREF Preparatory Fellowships (PF)

Study Design

The fellowship work will use peripheral blood mononuclear cells from a Ugandan clinical trial (ISRCTN60517191) that is investigating effects of intensive treatment of Schistosoma mansoni on vaccine responses, and from a comparison study in a lower helminth exposure, urban setting. The fellowship objectives are to Undertake hands-on laboratory training in mass cytometry (cytometry by time-of-flight; CyToF) technology at Leiden University Medical Center (LUMC; The Netherlands) in order to investigate pre-immunisation immunological parameters and cell populations that link helminth exposure to vaccine-specific immune responses. CyToF is an advanced system-wide approach that enables simultaneous detection of over 40 heavy metal-labelled immune markers at single-cell level, providing an opportunity to study heterogeneity and function of immune cells with unprecedented resolution. Undertake training in dimensionality reduction-based techniques for the analysis of CyToF and other complex multiparameter immunological data. CyToF generates large, non-linear data of high-dimensionality, posing a substantial challenge for analysis and presentation. The fellowship placement will provide training in machine learning algorithms using interactive visual analysis pipelines in place at LUMC. Algorithms such as T-distributed Stochastic Neighbor Embedding (tSNE) and Hierarchical SNE (HSNE) will be used. Generate pilot data for a follow-on international fellowship application on the impact of differential parasite exposure on immunological predictors of vaccine response. CyToF results from the fellowship will identify, in unpredented detail, cell subsets and pathways altered by helminth exposure and associated with vaccine response, generating hypotheses for testing in the follow-on study.

Project Summary

I will use knowledge and analysis skills obtained to build capacity in Uganda through peer trainings and seminars. The fellowship will augment collaboration with world leaders in immuno-parasitology at LUMC, and enhance the crucial mass of immunology expertise in sub-Saharan Africa. Together, the fellowship and follow-on studies will advance understanding of drivers of population differences in vaccine-specific responses, and inform both public health and biological strategies for maximising effectiveness of vaccines in the tropics.