Browsing by Author "Bayiyana, Alice"

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    CCR5 promoter variants among Ugandan HIV-1 elite and viremic controllers: a laboratory ฀ based cross ฀ sectional study
    (Research Square, 2020) Nyiro, Brian; Amanya, Sharon B.; Nabatanzi, Rose; Bayiyana, Alice; Kalazane, Linda I.; Waswa, Francis; Nabulime, Eva; Karara, Daniel; Kabali, Joel; Mboowa, Gerald; Kayongo, Alex; Kateete, David P.; Nankya, Immaculate
    Mechanisms for HIV control among HIV-1 elite and viremic-controllers are not fully understood. In Uganda, Studies have reported individuals who without Antiretroviral therapy have the inherent ability to control HIV progression to AIDS for a period of greater than 5 years. However, reasons for this phenotype are not understood. The study objective was to determine the distribution of CCR5 co-receptor on CD4+ T-cells and its associated promoter variants among HIV-1 elite and viremic-controllers. Methods We isolated CD4+T-cells from PBMCs using EasySep CD4+ T-cell negative selection kit, and stimulated them with anti-CD3 and anti-CD28 for 48 hours. To quantify CCR5 expression, we performed immune-phenotyping using flow cytometry. CCR5 promoter polymorphisms were determined through sanger sequencing. The Kruskal–Wallis and the Mann-Whitney test were used to compare differences in the percentages of CCR5+ CD4+ T-cells and the differences in CCR5 densities on CD4+ T-cells respectively. p values < 0.05 were considered significant. Results The percentage of CCR5+CD4+ T-cells was higher among the non-controllers compared to the controllers although, the difference was not statistically significant; elite and viremic-controllers (p=0.9173), viremic and non-controllers (0.0702), elite and non-controllers (0.6010). Of significance was the CCR5 densities on CD4+ T-cells, which were significantly higher among non-controllers relative to the controllers; elite and viremic-controllers (p=3048), viremic and non43 controllers (P=0.0312), elite and non-controllers (P=0.0210)
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    Immuno‑diagnosis of Mycobacterium tuberculosis in sputum, and reduction of timelines for its positive cultures to within 3 h by pathogen‑specific thymidylate kinase expression assays
    (BMC Research Notes, 2017-08-08) Wayengera, Misaki; Mwebaza, Ivan; Bayiyana, Alice; Joloba , Moses L.
    Laboratory diagnosis of Tuberculosis (TB) is traditionally based on microscopy and or culture. Microscopy is however, only sensitive to a specified degree of bacillary load not present in HIV co-infected persons. Traditional cultures of Mycobacterium tuberculosis (M. tb), on the other hand, take weeks to read—thereby delaying the critical decision whether or not, to treat. Although nucleic acids amplification tests (NAATS) applied directly on sputum or cultures can increase the sensitivity for TB diagnosis among those with HIV co-infection as well as reduce time-lines for positive culture detection, they do not replace the need for smear microscopy and culture. We have previously proposed the M. tb DNA-synthetic enzyme thymidylate kinase (aka TMKmt) as an organism-specific growth and proliferation biomarker to reduce time-lines for detection of positive TB cultures. In this study, we explored the secretory levels of TMKmt in M. tb cultures and sputum, towards improving the overall laboratory diagnosis of TB. Modelling of TMKmt secretion in vitro was done by cloning, expressing and SDS-PAGE/MALDI-TOF detection of purified recombinant TMKmt in E. coli. TMKmt expression profiling in M. tb was done by qRT-PCR assay of related messenger ribonucleic acids (mRNA) and TMKmt antigen detection by Enzyme linked Immuno-absorbent Assay (EIA) among cultures of a pathogenic wild-type Ugandan strain (genotype 1) alongside the H37Rv laboratory strain. Owing to the high-load of pathogen in-culture, direct EIA on limiting dilutions of sputum were done to examine for assay sensitivity. A rise in TMKmt antigen levels was observed at 3 h post-innoculation among in vitro cultures of E. coli. The 1st of several cyclic spikes in TMKmt mRNA and antigen levels were detected at 2.5 h among in vitro cultures of the pathogenic wild-type Ugandan isolate alongside the laboratory M. tb strain. TMKmt antigen was detected up to between 1 × 10−4–1 × 10−5 (containing 10 and 1 CFUs/ml) dilutions of a microscopically designated 1+ (est. Acid Fast Bacillary load of 1 × 105) patient sample. Detection of TMKmt expressed mRNA and Ag offers us opportune for instant diagnosis of M. tb in sputum, and reduction of timelines for positive pathogen detection in cultures to within 3 h.
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    Schistosoma mansoni Infection: A Major Contributor of Reduced Effective T Helper Responses against Plasmodium falciparum and Schistosoma mansoni Co-Infection in ex vivo: A Cross-Sectional Study to Assess Th1, Th2 & Th17 Immune Responses
    (Open Journal of Immunology, 2017) Candia, Rowel; Nabatanzi, Rose; Olobo, Joseph; Auma, Ann; Asiimwe, Benon; Mbabazi, Olive; Bayiyana, Alice; Enzaru, Annet; Tukahebwa, Edridah
    Parasitic worms evade immune responses, and interactions between diseases can cause altered immunologic outcomes compared to what usually occurs with single infections. These interactions may influence vaccine and chemotherapeutic efficacy. Schistosoma mansoni and Plasmodium falciparum are co-endemic in Uganda and are the leading parasitic causes of public health problems across sub-Saharan Africa. Objectives: The overall aim was therefore, to elucidate the impact of S. mansoni infection on protective T helper immune responses on P. falciparum and S. mansoni co-infection. Methodology: This study evaluated the T helper immune responses in individuals with independent S. mansoni infection, independent P. falciparum infection, co-infection and non-infection in school attending children in a co-endemic area along Lake Victoria shores, Uganda. Immune responses were categorized into Th1, Th2, and Th17 based on unique cytokine(s) produced by the T helper subpopulation in ex vivo. Kato Katz thick smears and circulating cathodic antigen tests were performed for S. mansoni screening, whereas thick and thin blood smear techniques were performed for P. falciparum screening. Results: We observed an up regulated Th1 T helper subpopulation in independent P. falciparum infections compared to the uninfected group. Suboptimal T helper immune responses were detected in independent S. mansoni infections characterized by significantly down regulated Th1 (Z = -1.425, p = 0.0313) response in comparison to the non-infected group. Suboptimal T helper immune responses were also recorded in the co-infected individuals characterized by significantly down regulated Th1 (Z = -3.260, p = 0.0273) and Th2 (Z = -1.180, p = 0.0078) responses compared to independent P. falciparum. Conclusions: S. mansoni infection is a major contributor of a reduced effective T helper immune response against P. falciparum in P. falciparum and S. mansoni co-infection.