University of Sri Jayawardanapura

Nugegoda, Sri Lanka

University of Sri Jayawardanapura

Nugegoda, Sri Lanka
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Nadugala M.N.,General Sir John Kotelawala Defence University | Jeewandara C.,University of Sri Jayawardanapura | Malavige G.N.,University of Sri Jayawardanapura | Premaratne P.H.,General Sir John Kotelawala Defence University | Goonasekara C.L.,General Sir John Kotelawala Defence University
PLoS ONE | Year: 2017

This study aims to characterize the antigenicity of the Capsid (C) protein and the human antibody responses to C protein from the four dengue virus (DENV) serotypes. Parker hydrophilicity prediction, Emini surface accessibility prediction and Karplus & Schulz flexibility predictions were used to bioinformatically characterize antigenicity. The human antibody response to C protein was assessed by ELISA using immune sera and an array of overlapping DENV2 C peptides. DENV2 C protein peptides P1 (located on C protein at 2-18 a.a), P11 (79-95 a.a) and P12 (86-101 a.a) were recognized by most individuals exposed to infections with only one of the 4 DENV serotypes as well as people exposed to infections with two serotypes. These conserved peptide epitopes are located on the amino (1-40 a.a) and carboxy (70-100 a.a) terminal regions of C protein, which were predicted to be antigenic using different bioinformatic tools. DENV2 C peptide P6 (39-56 a.a) was recognized by all individuals exposed to DENV2 infections, some individuals exposed to DENV4 infections and none of the individuals exposed to DENV1 or 3 infections. Thus, unlike C peptides P1, P11 and P12, which contain epitopes, recognized by DENV serotype cross-reactive antibodies, DENV2 peptide P6 contains an epitope that is preferentially recognized by antibodies in people exposed to this serotype compared to other serotypes. We discuss our results in the context of the known structure of C protein and recent work on the human B-cell response to DENV infection. © 2017 Nadugala et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Crack L.R.,Weatherall Institute of Molecular Medicine | Jones L.,Weatherall Institute of Molecular Medicine | Malavige G.N.,University of Sri Jayawardanapura | Patel V.,Weatherall Institute of Molecular Medicine | Ogg G.S.,Biomedical Research Center
Clinical and Experimental Dermatology | Year: 2012

Background. There is mounting evidence that antimicrobial peptides have an important role in cutaneous defence, but the expression of these antimicrobial peptides in atopic eczema (AE) is still unclear. There are several families of antimicrobial peptides, including cathelicidins and human β-defensins. Patients with AE are more susceptible to severe cutaneous viral infections, including varicella zoster virus (VZV). Aim. To characterize the functional activity of the antimicrobial peptides LL-37 (human cathelicidin) and human β-defensin (hBD)-2 keratinocytes were infected with VZV, in a skin-infection model. Methods. Flow-cytometry analysis was used to investigate LL-37 expression in normal human keratinocytes, and quantitative PCR was used to determine viral loads in infected HaCaT keratinocytes and B cells, with and without exogenous LL-37 and hBD-2. Results. LL-37 expression was present in keratinocytes, and both exogenous LL-37 and hBD-2 significantly reduced VZV load in infected keratinocytes and B cells. Specific antibodies blocked the antiviral action exhibited by these antimicrobial peptides. Preincubation of VZV with LL-37, but not hBD-2, further reduced VZV load. Conclusions. Both LL-37 and hBD-2 have an antiviral effect on VZV replication in the keratinocyte HaCaT cell line and in B cells, but their mechanism of action is different. Evidence of the relationship between antimicrobial peptide expression and higher susceptibility to infections in AE skin is still emerging. Developing novel antiviral therapies based on antimicrobial peptides may provide improved treatment options for patients with AE. © The Author(s) CED © 2012 British Association of Dermatologists.

Sinhabahu V.P.,Colombo South Teaching Hospital | Sathananthan R.,Colombo South Teaching Hospital | Malavige G.N.,University of Sri Jayawardanapura
BMC Research Notes | Year: 2014

Background: Dengue in pregnancy is associated with many maternal and foetal outcomes including perinatal transmission of dengue infection. Case Presentation: A baby was born by emergency caesarean section due to foetal distress and meconium stained liquor, to a 27-year old primi-gravidae, Sinhalese female, who was febrile during and 2 days prior to labour. The baby had evidence of respiratory distress due to meconium aspiration and was cared for in the special care baby unit for 3 days. On the 4th day he developed fever and serial blood counts showed a gradual rise in the haematocrit (>20% of baseline value) and lowering of platelet counts. The baby was treated for sepsis and as Sri Lanka was experiencing a massive dengue epidemic was also tested for dengue. His dengue NS1 antigen test was strongly positive and the dengue IgM antibodies weakly positive on day 3 of illness. The mother was positive for both dengue IgM and IgG antibodies. Conclusion: Although rare, vertical transmission of the dengue virus has been reported and the baby most likely developed dengue due to perinatal transmission of dengue.

Kamaladasa A.,University of Sri Jayawardanapura | Gomes L.,University of Sri Jayawardanapura | Jeewandara C.,University of Sri Jayawardanapura | Shyamali N.L.A.,University of Sri Jayawardanapura | And 5 more authors.
Antiviral Research | Year: 2016

Background Platelet Activating Factor (PAF) has been shown to be an important mediator of vascular leak in acute dengue. Antibody dependent enhancement (ADE) and microbial translocation has also shown to contribute to severe dengue. Since monocytes are one of the primary targets of the dengue virus (DENV) we sought to investigate if monocytes were a source of PAF, and the effect of ADE and microbial endotoxin (LPS) on DENV infected monocytes. Methods PAF and cytokine levels were evaluated in serial blood samples, in patients with acute dengue infection. The effect of ADE and LPS in production of PAF and cytokines from DENV infected primary human monocytes derived macrophages (MDMθ) was assessed. Gene expression analysis was undertaken to investigate mechanisms by which LPS potentiates PAF and cytokine production by DENV infected MDMθ. Results Serum PAF levels significantly correlated with both TNF-α (p < 0.0001) and IL-1β (p < 0.0001) in patients with acute DENV infection. Although primary human MDMθ produced inflammatory cytokines following infection with the DENV, they did not produce PAF following in vitro DENV infection alone, or in the presence of dengue immune serum. Levels of PAF produced by DENV infected MDMθ co-cultured with LPS was significantly higher than uninfected MDMθs co-cultured with LPS. Although TLR-4 was upregulated in uninfected MDMθs co-cultured with LPS, this upregulation was not significant in DENV infected MDMθ. Only expression of RIG-I was significantly up regulated (p < 0.05) when DENV infected MDMθ were co-cultured with LPS. Conclusion LPS acts synergistically with the DENV to induce production of PAF and other inflammatory cytokines, which suggests that microbial translocation that has shown to occur in acute dengue, could contribute to dengue disease severity. © 2016 Elsevier B.V.

Malavige G.N.,University of Sri Jayawardanapura | Malavige G.N.,Weatherall Institute of Molecular Medicine | Rostron T.,Weatherall Institute of Molecular Medicine | Rohanachandra L.T.,University of Sri Jayawardanapura | And 6 more authors.
PLoS ONE | Year: 2011

Background: HLA class I and class II alleles have been shown to be associated with the development of dengue hemorrhagic fever (DHF)/dengue shock syndrome (DSS) in different populations. However, the majority of studies have been based on limited numbers of patients. In this study we aimed to investigate the HLA-class I and class II alleles that are positively and negatively associated with the development of DSS in a cohort of patients with DHF and also the alleles associated with development of DHF during primary dengue infections in a Sri Lankan population. Methodology/Principal Findings: The allele frequencies of HLA class I and class II alleles were compared in 110 patients with DHF and 119 individuals from the population who had never reported a symptomatic dengue infection at the time of recruitment. We found that HLA-A*31 (corrected P = 0.01) and DRB1*08 (corrected P = 0.009) were associated with susceptibility to DSS when infected with the dengue virus, during secondary dengue infection. The frequency of DRB1*08 allele was 28.7 times higher than in the normal population in patients with DSS. HLA-A*31 allele was increased 16.6 fold in DHF who developed shock when compared to those who did not develop shock. A*24 (corrected P = 0.03) and DRB1*12 (corrected P = 0.041) were strongly associated with the development of DHF during primary dengue infection. Conclusions/Significance: These data suggest that certain HLA alleles confer susceptibility/protection to severe dengue infections. As T cell epitope recognition depend on the HLA type of an individual, it would be now important to investigate how epitope specific T cells associate with primary and secondary dengue infections and in severe dengue infections. © 2011 Malavige et al.

Taira B.R.,Stony Brook University Medical Center | Cherian M.N.,World Health Organization | Yakandawala H.,World Health Organization | Kesavan R.,World Health Organization | And 2 more authors.
World Journal of Surgery | Year: 2010

Background: Three decades of internal conflict in the North and East of Sri Lanka have taken a toll on the health care system in that area. Methods: We proposed to quantify the current status of capacity to deliver emergency, anesthesia, and surgical interventions in the conflict affected areas of Sri Lanka. The World Health Organization (WHO) Tool for Situational Analysis to Assess Emergency and Essential Surgical Care (EESC) was used to evaluate 47 health facilities. Results: Although most have trained health care providers capable of basic procedures, infrastructure and supplies were severely lacking. Conclusion: These data can be used as a basis for the recovery and rebuilding of EESC capacity in conflict-affected areas of Sri Lanka. © 2009 Société Internationale de Chirurgie.

Malavige G.N.,University of Sri Jayawardanapura | Malavige G.N.,Weatherall Institute of Molecular Medicine | Ogg G.S.,Weatherall Institute of Molecular Medicine | Ogg G.S.,Churchill Hospital
Journal of Clinical Virology | Year: 2013

Dengue viral infections are the commonest mosquito borne viral infection in the world, affecting more than 100 countries and 390 million individuals annually. Currently, there are no effective antiviral drugs or an effective vaccine to prevent infection. A main hurdle in developing a safe and effective vaccine has been our poor understanding of the complex nature of the protective immune response in acute dengue infection and the presence of four dengue virus (DV) serotypes that are highly homologous. The role of DV specific T cells in the pathogenesis of severe clinical disease in not clear. It has been speculated that highly cross reactive T cells for the previous infecting heterologous DV serotype, which produce pro-inflammatory cytokines, contribute to disease pathogenesis. These cross reactive T cells are believed to be suboptimal in clearing the infection with the current DV-serotype. However, other studies have shown that cross-reactive DV-specific T cells are absent or present in very low frequency during acute infection, appearing only during the convalescent period in the majority of patients. Furthermore, significant apoptosis of T cells occurs in severe acute clinical disease. Overall therefore, it is unclear what role T cells play in contributing to disease pathogenesis during acute dengue infection. Existing data have been complicated by cross-reactivity in T cells assays. These findings can now be re-evaluated in the light of novel technologies to identify serotype-specific T cell responses. © 2013 Elsevier B.V.

Malavige G.N.,University of Sri Jayawardanapura | Malavige G.N.,Weatherall Institute of Molecular Medicine | Huang L.-C.,Weatherall Institute of Molecular Medicine | Salimi M.,Weatherall Institute of Molecular Medicine | And 4 more authors.
PLoS ONE | Year: 2012

Background: The occurrence of dengue haemorrhagic fever (DHF) is thought to result from a complex interplay between the virus, host genetics and host immune factors. Existing published data are not consistent, in part related to relatively small sample sizes. We set out to determine possible associations between dengue virus (DEN-V) NS3 specific T cells and cytokine and chemokine levels and the pathogenesis of severe disease in a large cohort of individuals with DHF. Methodology/Principal Findings: By using ex vivo IFNγ ELISpot assays we determined DENV-NS3 specific responses in patients with varying severity of DHF. Other cytokines produced by DENV-NS3 specific T cells were determined by using multiple bead array analysis (MBAA). We also determined the serum cytokine levels using MBAA, lymphocyte subsets and Annexin V expression of lymphocytes in patients with varying severity of DHF. Of the 112 DHF patients studied, 29 developed shock. Serum IL-10 and IP-10 levels positively and significantly correlated with T cell apoptosis while IL-10 levels inversely correlated with T cell numbers. In contrast, TGFß showed a very significant (P<0.0001) and positive correlation (Spearman's R = 0.65) with the platelet counts, consistent with platelet release. We found that whilst patients with severe dengue had lower total T cell numbers, the DV-NS3 specific T cells persisted and produced high levels of IFNγ but not TNFα, IL-3, IL-13, IL-2, IL-10 or IL-17. Conclusions/Significance: Our data suggest that serum IL-10, TNFα and TGFβ differentially associate with dengue disease severity. © 2012 Malavige et al.

Malavige G.N.,University of Sri Jayawardanapura | Malavige G.N.,Weatherall Institute of Molecular Medicine | Jeewandara C.,University of Sri Jayawardanapura | Alles K.M.L.,University of Sri Jayawardanapura | And 6 more authors.
PLoS Neglected Tropical Diseases | Year: 2013

Background:Elevated IL-10 has been shown to be associated with severe dengue infection (DI). We proceeded to investigate the role of IL-10 in the pathogenesis of acute DI.Materials and methods:Ex vivo and cultured IFNγ ELISpot assays for dengue virus (DENV) NS3 protein and non dengue viral proteins were carried out in 26 patients with acute DI (16 with dengue haemorrhagic fever) and 12 healthy dengue seropositive individuals from Sri Lanka. DENV serotype specific (SS) responses were determined by using a panel of SS peptides.Results:Serum IL-10 level were significantly higher (p = 0.02) in those who did not have in vitro responses to DENV-SS peptides (mean 144.2 pg/ml) when compared to those who responded (mean 75.7 pg/ml). DENV-NS3 specific ex vivo IFNγ ELISpot responses were also significantly lower (p = 0.0001) in those who did not respond to DENV-SS peptides (mean 42 SFU/million PBMCs) when compared to those who responded to DENV-SS peptides (mean 1024 SFU/million PBMCs). Serum IL-10 levels correlated significantly (p = 0.03) and inversely (Spearmans R = -0.45) with ex vivo DENV-NS3 specific responses but not with ex vivo non DENV specific responses (Spearmans R = -014, p = 0.52). Blockage of IL-10 in vitro significantly increased (p = 0.04) the ex vivo IFNγ ELISpot DENV-NS3 specific responses but had no effect on responses to non DENV proteins.Conclusion:IL-10 appears to contribute to the pathogenesis of acute dengue infections by inhibiting DENV-specific T cell responses, which can be restored by blocking IL-10. © 2013 Malavige et al.

Malavige G.N.,University of Sri Jayawardanapura | Malavige G.N.,Weatherall Institute of Molecular Medicine | Gomes L.,University of Sri Jayawardanapura | Alles L.,University of Sri Jayawardanapura | And 6 more authors.
BMC Infectious Diseases | Year: 2013

Background: Several studies have shown that serum IL-10, IFNγ and MIF are elevated in patients in severe dengue (SD) and could be used as potential biomarkers. We proceeded to determine if these cytokines could be used as biomarkers in a large cohort of adult dengue patients with varying severity of dengue infection.Methods: Serum IL-10 levels were determined in 259 of whom 40 had severe dengue infection. Serum IFNγ and IFNα levels were done in 78 and MIF levels were done in 65 patients with acute dengue infection. Clinical features and laboratory investigations were undertaken during the febrile and critical phase.Results: We found that serum IL-10 levels were significantly higher (p = 0.001) in patients with SD, when compared to those with non SD. Serum IL-10 levels significantly and inversely correlated with white cell counts (R = -0.23, p = 0.0002) and lymphocyte counts (R = -0.29, p < 0.0001) but significantly and positively correlated with aspartate tranaminase levels (R = 0.16, p = 0.01) and alanine transaminase levels (R = 0.22, p = 0.007). However, IL-10 levels did not have a good predictive value in discriminating those who were likely to develop SD (AUC = 0.66). Serum IFNγ levels were also significantly higher (p = 0.04) in patients with SD when compared to non SD. There was no difference (p = 0.34) in serum IFNα levels and serum MIF levels (p = 0.15) in patients with SD and non SD.Conclusion: Although serum IL-10 was significantly elevated in patients with SD it had a poor discriminatory value in identifying those with SD and non SD and therefore, is unsuitable to be used as a robust biomarker in this cohort. © 2013 Malavige et al.; licensee BioMed Central Ltd.

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