An Immunoinformatics Approach for SARS-CoV-2 in Latam Populations and Multi-Epitope Vaccine Candidate Directed Towards the World’s Population

The coronavirus pandemic is a major public health crisis affecting global health systems with dire socioeconomic consequences, especially in vulnerable regions such as Latin America (LATAM). There is an urgent need for a vaccine to help control contagion, reduce mortality and alleviate social costs. In this study, we propose a rational multi-epitope candidate vaccine against SARS-CoV-2. Using bioinformatics, we constructed a library of potential vaccine peptides, based on the affinity of the most common major human histocompatibility complex (HLA) I and II molecules in the LATAM population to predict immunological complexes among antigenic, non-toxic and non-allergenic peptides extracted from the conserved regions of 92 proteomes. Although HLA-C, had the greatest antigenic peptide capacity from SARS-CoV-2, HLA-B and HLA-A, could be more relevant based on COVID-19 risk of infection in LATAM countries. We also used three-dimensional structures of SARS-CoV-2 proteins to identify potential regions for antibody production. The best HLA-I and II predictions (with increased coverage in common alleles and regions evoking B lymphocyte responses) were grouped into an optimized final multi-epitope construct containing the adjuvants Beta defensin-3, TpD, and PADRE, which are recognized for invoking a safe and specific immune response. Finally, we used Molecular Dynamics to identify the multi-epitope construct which may be a stable target for TLR-4/MD-2. This would prove to be safe and provide the physicochemical requirements for conducting experimental tests around the world.

Immunoinformatic based identification of cytotoxic T lymphocyte epitopes from the Indian isolate of SARS-CoV-2

The Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has turned into a pandemic with about thirty million confirmed cases worldwide as of September 2020. Being an airborne infection, it can be catastrophic to populous countries like India. This study sets to identify potential cytotoxic T lymphocyte (CTL) epitopes in the SARS-CoV-2 Indian isolate which can act as an effective vaccine epitope candidate for the majority of the Indian population. The immunogenicity and the foreignness of the epitopes towards the human body have to be studied to further confirm their candidacy. The top-scoring epitopes were subjected to molecular docking studies to study their interactions with the corresponding human leukocyte antigen (HLA) system. The CTL epitopes were observed to bind at the peptide-binding groove of the corresponding HLA system, indicating their potency as an epitope candidate. The candidacy was further analyzed using sequence conservation studies and molecular dynamics simulation. The identified epitopes can be subjected to further studies for the development of the SARS-CoV-2 vaccine.

In Silico Characterization of Epitopes from Human Rotavirus VP7 Genotype G9 Design for Vaccine Development

Acute gastroenteritis caused by Rotavirus remains the leading cause of child mortality worldwide. Rotavirus genotype G9 circulates in humans throughout the world. Antibodies against the outer glycoproteins VP7 and VP4 Rotavirus capsid are the main neutralization antibodies in the vaccine assessment. This study aimed to select an epitope to evoke T and B cells' response, as a favorable candidate for vaccine development using in Silico evaluation. In the present study, Rotavirus genotypes were determined in 100 stools specimens collected from children with acute diarrhea. The results showed predominant G genotype, G9 (38.5%) followed by G2 (22.9%), G1 (16.5%), G12 (11.4%), G4 (6.4%), and G3 (4.3%). The G9 was dominant in this study and other regions of Iran; thus, this study was conducted to select an epitope from Rotavirus genotype G9 as a promising epitope candidate for future vaccine development. For this reason, several works including a complete sequence of VP7 G9, phylogenetic analysis, Prediction of Protein Structure, Physicochemical Properties of Protein and Epitope prediction were carried out. The outcomes of this study revealed that the complete sequence of VP7 (G9) was comprised of 1062 nt with 326 amino acids (accession number MH824633). The selected epitope contained amino acid sequence of STLCLYYPTEASTQIGDTEWKN with the best score for T and B cells response. Based on data of computational biology, the selected epitope can optimistically have considered as an epitope candidate for Rotavirus vaccine development.