Single cell sequencing to differentiate between protective and pathological T cell clonotypes and phenotypes in Mycobacterium tuberculosis infections

• Applicant: Jana Jiang
• Subject Area: Immunology ; Ophthalmology ; Human Genetics
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 531855214

The project’s aim is to differentiate between protective and pathological T cell clonotypes and phenotypes in patients with Mycobacterium tuberculosis (Mtb) infections since only a fraction of 5-10% of people infected with Mtb will develop active Tuberculosis at some point during their lifetime. We hypothesise that protective and pathogenic T cells exhibit distinct “context-specific” clonal and functional repertoires. This would be best evaluated by comparing patients in three clinical states, which are likely to reflect differential enrichment of protective and pathogenic T-cell recall responses. Patients with positive Interferon-Gamma-Release-Assays (IGRAs; detect immune response to Mtb) are recruited from across five NHS trusts in London. Patients with active TB disease are thought to reflect pathogenic T cell responses, recently infected individuals without disease represent protective T cell responses and patients who have completed curative antimicrobial treatment for TB or had remote asymptomatic infections (>two years) are inferred to have a restored immune homeostasis and a loss of enrichment for either protective or pathogenic T cells. Both ex vivo and in vivo experiments will be conducted with cryopreserved peripheral blood mononuclear cells (PBMC) and tuberculin skin tests (TST) respectively, beginning with 10 patients per group. Between-group comparisons of transcriptional profiles will be made, reflecting cellular function stratified by cell type and T cell receptor (TCR) clonotype clusters. Between-group comparisons of the clonal diversity (richness and inequality) and clonal relatedness within individuals (reflecting an immunodominant response) and between individuals within groups (reflecting shared or public responses) will also be performed. Overall, this research opportunity can inform novel targeted approaches to the treatment of immunopathogenesis, and use correlates of protection to inform novel vaccine design, or to undertake early phase evaluation of vaccine efficacy. Learning about single-cell RNA sequencing of T-cell populations is valuable for studying immunopathology in eye diseases in the future. So far, there is no expertise at the University Eye Center Freiburg to carry out single-cell sequencing and to analyse the transcriptomic profiles generated. Experience and expertise in this field will be useful for further research into the plasticity and expression of T cell populations, such as T regulatory (Treg) and T helper 17 (Th17) cells, in dry eye disease and uveitis as well as ocular gene expression from a diverse range of ocular tissues.

• DFG Programme: WBP Fellowship
• International Connection: United Kingdom
• Host: Professor Dr. Mahdad Noursadeghi