Journal/Magazine Articles

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This collection contains original research articles, review articles and case reports published in local and international peer reviewed journals by the staff members of the Faculty of Medicine

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    Immuno-dominant dengue NS1 peptides as antigens for production of monoclonal antibodies
    (Frontiers Media S.A, 2022) Munasinghe, E.; Athapaththu, M.; Abeyewickreme, W.
    Synthetic peptides have recently become common as antigens for antibody production. Peptides are short chains of amino acids that can be used to elicit an immune response. The immunogenicity of the peptide antigens varies depending on the length, charge, solubility, and amino acids contained in the peptide sequence. Dengue NS1 protein is an important target antigen in the early detection of dengue infection. In this study, peptides corresponding to a highly conserved region from the dengue NS1 region were designed and synthesized. Balb/C mice were immunized against each peptide and spleen cells extracted from the immunized mice were fused with NS0 murine myeloma cells. Hybridoma clones obtained from the fusions were tested against peptides using ELISA. Out of 1,830 growing clones, 28 clones produced antibodies reacting with dengue NS1 peptides. A purified monoclonal antibody reacting with all four peptides was tested for reactivity with dengue NS1 native protein using dengue-confirmed serum and urine samples. The monoclonal antibody shows significant reactivity with both serum and urine. The findings of the current research can be used to detect dengue infection using urine, which ultimately results in the prevention of dengue epidemics through painless diagnosis, following treatment, and patient management to safeguard human and economic wellness.
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    Development of an in-house ELISA as an alternative method for the serodiagnosis of leptospirosis
    (Elsevier, 2021) Niloofa, R.; Karunanayake, L.; de Silva, H.J.; Premawansa, S.; Rajapakse, S.; Handunnetti, S.
    BACKGROUND: Leptospirosis is most often clinically diagnosed and a laboratory test with high diagnostic accuracies is required. METHODOLOGY: IgM and IgG-ELISAs using Leptospira antigens were established and evaluated in relation to the Microscopic Agglutination Test (MAT). Antigen preparation consisted either saprophytic Leptospira biflexa to detect genus specific antibodies (genus-specific ELISA) or a pool of five most prevalent Leptospira interrogans serovars in Sri Lanka to detect serovar specific antibodies (serovar-specific ELISA). IgM and IgG immune responses in severe and mild leptospirosis patients (n = 100 in each group) were studied. RESULTS: ELISAs showed high repeatability and reproducibility. Serovar-specific IgM-ELISA showed sensitivity of 80.2% and specificity of 89%; genus-specific IgM-ELISA showed sensitivity of 83.3% and specificity of 91%. Serovar and genus-specific IgG-ELISA showed sensitivities of 73.3% and 81.7%, and specificities of 83.33%. Commercial IgM-ELISA showed sensitivity and specificity of 79.2% and 93% respectively. Commercial IgG-ELISA showed sensitivity, specificity of 50% and 96.7% respectively. IgM levels observed in mild and severe leptospirosis (ML & SL) patients were significantly higher than healthy control (HC) group, having absorbance mean of 0.770, 0.778 and 0.163 respectively. In contrast, SL patients had significantly higher mean anti-leptospiral IgG levels compared to both ML and HC groups (0.643, 0.358 and 0.116 respectively; ANOVA, P < 0.001). Presence of anti-leptospiral IgG above OD 0.643 optical density (OD) at 1:100 could predict high risk of severe disease. CONCLUSION: Serovar-specific In-House ELISAs could be used for the laboratory diagnosis of leptospirosis in endemic settings. Observed high levels of anti-leptospiral IgG suggest its value as a predictor for disease severity. KEYWORDS: IgM and IgG antibodies; In-House ELISA; Leptospirosis; Sero-diagnosis.