ABSTRACT
Introduction: The emergence of a novel coronavirus in China has turned into a SARS-CoV-2 pandemic with high fatality. As vaccines are developed through various strategies, their immunogenic potential may drastically vary and thus pose several challenges in offering immune responses against the virus. Methods: In this study, we adopted an immunoinformatics-aided approach for developing a new multi-epitope vaccine construct (MEVC). In silico approach was taken for the identification of B-cell and T-cell epitopes in the Spike protein, for MEVC various cytotoxic T-lymphocyte, helper T-lymphocyte, and B-cell epitopes with the highest affinity for the respective HLA alleles were assembled and joined by linkers. Results: The computational data suggest that the MEVC is nontoxic, nonallergenic and thermostable and elicit both humoral and cell-mediated immune responses. Subsequently, the biological activity of MEVC was assessed by bioinformatic tools using the interaction between the vaccine candidate and the innate immune system receptors TLR3 and TLR4. The epitopes of the construct were analyzed with that of the strains belonging to various clades including the emerging variants having multiple unique mutations in S protein. Conclusions: Due to the advantageous features, the MEVC can be tested in vitro for more practical validation and the study offers immense scope for developing a potential vaccine candidate against SARS-CoV-2 in view of the public health emergency associated with COVID-19 disease caused by SARS-CoV-2.
ABSTRACT
Chikungunya Virus (CHIKV) is a single stranded positive sense enveloped RNA virus. Re-emergence of CHIKV caused a massive outbreak with severe clinical manifestation affecting multiple organs. The genetic diversity of CHIKV, which caused recurring outbreaks in India, was studied. Blood samples were collected from suspected human cases of CHIKV infection in Chennai, Tamil Nadu and three Northern districts of Kerala in Southern India during the CHIKV outbreak in 2009. A partial E2 gene segment was amplified by RT-PCR. Among 119 samples 37 samples were positive for CHIKV by RT-PCR. Phylogenetic analysis revealed that the isolated sequences belonged to Indian Ocean Lineage (IOL) of ECSA genotype. The mutational analysis revealed the presence of substitutions such as S299N, T312M, A344T, S375T, V386G, W339R and S375P in the current study. In addition, a novel mutation V386G was observed in all the sequences. Two isolates found with unique substitutions W339R and S375P are reported. The structural analysis of the wild type and mutant proteins revealed that the structural changes are accompanied by modification in the intraprotein interactions.
