The cross-reactivity of human humoral and cellular immune responses to Burkholderia pseudomallei and avirulent Burkholderia species. (360G-Wellcome-108395_Z_15_Z)

Burkholderia pseudomallei is the Gram negative bacterial cause of melioidosis, a sepsis disease with 40% in-hospital mortality in Northeast Thailand and surrounding regions. Seroconversion to positive indirect haemagluttination assay has traditionally been considered a marker of exposure to B. pseudomallei, and has been used in diagnostics, but the role of avirulent environmental bacteria such as B. thailandensis and B. thailandensis CPS variant in positive serology and protection from disease a nd death is unknown. Samples from two clinical studies offer a unique opportunity to measure cross-reactivity of humeral and cellular responses to the three bacterial species. In the first study samples from approximately 100 rice farmers in three regions of Thailand are paired with bacterial isolates from fields associated with each farmer, to evaluate the relationship between responses and environmental prevalence. In the second study samples from 100 patients with culture-confirmed melioid osis in Northeast Thailand at Weeks 0, 12 and 52 where available will be studied alongside healthy controls. Cross-reactive responses will be characterised by IHA, ELISA, functional antibody assays, multiparameter flow cytometry, cytokine stimulation assays and interferon-gamma ELIspot assay. The results will advance B. pseudomallei specific diagnostics and effective vaccine design.