Browsing by Author "Tukahebwa, Edridah M."

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    Antibody Responses to Schistosoma Mansoni Schistosomula Antigens
    (Parasite immunology, 2018) Egesa, Moses; Lubyayi, Lawrence; Jones, Frances M.; Tukahebwa, Edridah M.; Bagaya, Bernard S.; Dunne, David W.; Elliott, Alison M.; Wilson, Shona; Cose, Stephen
    While antigens from Schistosoma schistosomula have been suggested as potential vaccine candidates, the association between antibody responses with schistosomula antigens and infection intensity at reinfection is not well known. Schistosoma mansoni-infected individuals were recruited from a schistosomiasis endemic area in Uganda (n = 372), treated with 40 mg/kg praziquantel (PZQ) and followed up at five weeks and at one year post-treatment. Pre-treatment and five weeks post-treatment immunoglobulin (Ig) E, IgG1 and IgG4 levels against recombinant schistosomula antigens rSmKK7, rSmLy6A, rSmLy6B and rSmTSP7 were measured using ELISA. Factors associated with detectable pre-treatment or post-treatment antibody response against the schistosomula antigens and the association between five-week antibody responses and one year post-treatment reinfection intensity among antibody responders were examined. Being male was associated with higher pre-treatment IgG1 to rSmKK7, rSmLy6a and AWA. Five weeks post-treatment antibody responses against schistosomula antigens were not associated with one year post-treatment reinfection intensity among antibody responders’ antibody levels against rSmKK7, rSmLy6B and rSmTSP7 dropped, but increased against rSmLy6A, AWA and SEA at five weeks post-treatment among antibody responders. S. mansoni-infected individuals exhibit detectable antibody responses to schistosomula antigens that are affected by treatment. These findings indicate that schistosomula antigens induce highly varied antibody responses and could have implications for vaccine development.
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    Completing Baseline Mapping of Trachoma in Uganda: Results of 14 Population-Based Prevalence Surveys Conducted in 2014 and 2018
    (Informa UK Limited, 2018-12-28) Baayenda, Gilbert; Francis Mugume; Turyaguma, Patrick; Tukahebwa, Edridah M.; Binagwa, Ben; Onapa, Ambrose; Agunyo, Stella; Osilo, Martin K.; French, Michael D.; Thuo, Wangeci; Rotondo, Lisa A.; Renneker, Kristen; Willis, Rebecca; Bakhtiari, Ana; Harding-Esch, Emma M.; Solomon, Anthony W.; Ngondi, Jeremiah M.
    Purpose: We aimed to estimate the prevalence of trachomatous inflammation—follicular (TF) in children aged 1–9 years, trichiasis in adults aged ≥15 years, and water and sanitation (WASH) indicators in 12 suspected-endemic districts in Uganda. Methods: Surveys were undertaken in 14 evaluation units (EUs) covering 12 districts. Districts were selected based on a desk review in 2014 (four districts) and trachoma rapid assessments in 2018 (eight districts). We calculated that 1,019 children aged 1–9 years were needed in each EU to estimate TF prevalence with acceptable precision and used three-stage cluster sampling to select 30 households in each of 28 (2014 surveys) or 24 (2018 surveys) villages. Participants living in selected households aged ≥1 year were examined for trachoma; thus enabling estimation of prevalences of TF in 1–9 year-olds and trichiasis in ≥15 year-olds. Household-level WASH access data were also collected. Results: A total of 11,796 households were surveyed; 22,465 children aged 1–9 years and 24,652 people aged ≥15 years were examined. EU-level prevalence of TF ranged from 0.3% (95% confidence interval [CI] 0.1–0.7) to 3.9% (95% CI 2.1–5.8). EU-level trichiasis prevalence ranged from 0.01% (95% CI 0–0.11) to 0.81% (95% CI 0.35–1.50). Overall proportions of households with improved drinking water source, water source in yard or within 1km, and improved sanitation facilities were 88.1%, 23.0% and 23.9%, respectively. Conclusion: TF was not a public health problem in any of the 14 EUs surveyed: antibiotic mass drug administration is not required in these districts. However, in four EUs, trichiasis prevalence was ≥ 0.2%, so public health-level trichiasis surgery interventions are warranted. These findings will facilitate planning for elimination of trachoma in Uganda.
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    Schistosoma Mansoni schistosomula Antigens Induce Th1/ Pro-inflammatory Cytokine Responses
    (Parasite immunology, 2018) Egesa, Moses; Lubyayi, Lawrence; Tukahebwa, Edridah M.; Bagaya, Bernard S.; Wilson, Shona; Yazdanbakhsh, Maria; Labuda, Lucja A.; Cose, Stephen
    Larvae of Schistosoma (schistosomula) are highly susceptible to host immune responses and are attractive prophylactic vaccine targets, although cellular immune responses against schistosomula antigens in endemic human populations are not well characterized. We collected blood and stool from 54 Schistosoma mansoni-infected Ugandans, isolated peripheral blood mononuclear cells and stimulated them for 24 hours with schistosome adult worm and soluble egg antigens (AWA and SEA), along with schistosomula recombinant proteins rSmKK7, Lymphocyte Antigen 6 isoforms (rSmLy6A and rSmLy6B), tetraspanin isoforms (rSmTSP6 and rSmTSP7). Cytokines, chemokines and growth factors were measured in the culture supernatants using a multiplex luminex assay, and infection intensity was determined before and at 1 year after praziquantel (PZQ) treatment using the Kato-Katz method. Cellular responses were grouped and the relationship between groups of correlated cellular responses and infection intensity before and after PZQ treatment was investigated. AWA and SEA induced mainly Th2 responses. In contrast, rSmLy6B, rSmTSP6 and rSmTSP7 induced Th1/pro-inflammatory responses. While recombinant antigens rSmKK7 and rSmLy6A did not induce a Th1/pro-inflammatory response, they had an association with pre-treatment infection intensity after adjusting for age and sex. Testing more schistosomula antigens using this approach could provide immune-epidemiology identifiers necessary for prioritizing next generation schistosomiasis vaccine candidates.