Studies on Dengue Virus Infection Genetic Characterization Th1 and Th2 Cytokine Response and Development of Novel Anti Dengue Drug

Abstract

The classic presentation of dengue fever (DF) has expanded its horizon by involving severe forms as atypical manifestations, denguehemorrhagic fever (DHF) and currently there is no drug. This study aimed to evaluate the clinical profile, characterizationof dengue viruses (DENV) causing DHF, compare the Th1/Th2cytokines levels and to study the anti Dengue activity. Clinically suspected cases of DF were confirmed by ELISA. Serum samples were subjected to reverse transcriptase polymerase chain reaction (RT-PCR), sequenced, aligned and serotype based phylogenetic analysis was performed. IFN-and#947;, IL-2, IL-4 and IL-10 concentration were quantifiedby ELISA and anti-dengue virus activity of A. paniculata and M. Azadirachta was estimated by CPE reduction assay. A total of 434 cases were screened, of which 146 (34%) samples were positive for dengue infection. 47 (32%) cases showed atypical denguemanifestations, 14 (9.5%) presented with DHF. Among the atypical manifestations, hepatomegaly and splenomegaly were the most common. DHF (n = 14) was caused by, DENV-1 (n = 7), DENV-2 (n = 5) and DENV- 4 (n = 2). A new clade of genotype I (GI) was predominant in DENV-1; Genotype IVC (GIVC) was predominant in DENV-2 showing mixed clustering suggesting lineage C; clade B of lineage C, genotype I (GI) was seen in DENV-4. The amino acid changes were observed in M51I, L72F, S93N in DENV-1 and M104V, V112A in DENV-2 of C-prM regions of DHF isolates when compared to standard strains. IFN-and#947;, IL-2 and IL-10, showed a statistically significant increase in acute dengue patients, dengue with atypical manifestation and DHF when compared to healthy controls. 150µg/ml concentration of A. paniculata and M. Azadirachta completely inhibited Dengue virus and the drug was found to be non-toxic up to 1.5 mg/ml.Multiple amino acid changes may have influenced the emergence of new clade, lineages and resulted as DHF. paniculata and M. Azadirachta was thus found to be a potent inhibitor of Dengue virus.