Homology modelling of frequent HLA class-II alleles: A perspective to improve prediction of HLA binding peptide and understand the HLA associated disease susceptibility

West Nile virus-associated HLA-DRB1 alleles in the Greek population: A structural perspective

The HLA system plays a significant role via the regulation of the immune system and contributes to the progression and protection of many diseases. In our previous study, several HLA-DRB1 alleles were found to have a susceptible or protective role toward infection and neuroinvasion of West Nile Virus (WNV) in the Greek population. As expected, the majority of polymorphic positions are located in the peptide-binding region of the molecule. In the present work, the structure of these alleles was studied in silico, to examine the effect of polymorphism on the conformation of DRB1 proteins, with the aspect of WNV association. More specifically, molecular dynamics simulations were used for structural prediction of 23 available alleles. These modeled alleles were evaluated using root-mean-square deviation (RMSD) and root-mean-square fluctuation analysis. Low RMSD values indicate that different alleles have similar structures. Furthermore, low fluctuation was observed in the peptide-binding region between alleles with the higher and the lowest RMSD values. These findings indicate that probably variable residues do not affect the behavior of DRB1 alleles in WNV disease, by causing structural differences between them.

Chikungunya Virus Infection Outcome: A Systematic Review of Host Genetics

Background: Chikungunya virus (CHIKV) is a global concern, inducing chikungunya fever and trigging an arthritogenic chronic phase beyond some severe forms. Outcomes of CHIKV infections in humans are dependent on genetic variations. Here, a systematic review was performed to show evidence of genetic variations on infection outcomes of patients. Methods: Searches were performed in Scopus, SciELO, MEDLINE/PubMed, Web of Science, OneFile (GALE), Periódicos CAPES and ScienceDirect Journals databases. The PICOS approach was used to assess the eligibility of records. A meta-analysis was also conducted to show an association between described alleles/genes and CHIKV infection outcome. Results: Reviews of genetic variants were conducted on genes: CD 209, OAS1, OAS2, OAS3, MIF, TLR-3, TLR-7, TLR-8, MYD-88, KIR, HLA-B; HLA-C; DRB1 and DQB1. Studies were performed on Gabon, Singapore, and India, including Indians, Malay, Gabonese and Chinese ethnicities and published between 2009-2017. The meta-analysis was performed with DRB1 *01; *03; *04; *07; *10; *11; *13; *14 and *15 and DQB1 *02; *03; *05 and *06 alleles with Indian population sample. Sampling power was >80% and a significant positive association between DRB1*14 and CHIKV infection was found (OR = 1.67, 95% CI = 1.04-2.67; p = .03). Conclusion: Majority of the studies were conducted in India. Meta-analysis suggests that DRB1*14 is related to the susceptibility of symptomatic CHIKV infection in Indian population. The literature about CHIKV infection and genetic variations is scarce. The precise role of genetic variation in CHIKV is not clear yet. Further studies are necessary to provide more concrete evidences.

Prediction and analysis of promiscuous T cell-epitopes derived from the vaccine candidate antigens of Leishmania donovani binding to MHC class-II alleles using in silico approach

Visceral leishmaniasis is a dreadful infectious disease and caused by the intracellular protozoan parasites, Leishmania donovani and Leishmania infantum. Despite extensive efforts for developing effective prophylactic vaccine, still no vaccine is available against leishmaniasis. However, advancement in immunoinformatics methods generated new dimension in peptide based vaccine development. The present study was aimed to identify T-cell epitopes from the vaccine candidate antigens like Lipophosphogylcan-3(LPG-3) and Nucleoside hydrolase (NH) from the L. donovani using in silico methods. Available best tools were used for the identification of promiscuous peptides for MHC class-II alleles. A total of 34 promiscuous peptides from LPG-3, 3 from NH were identified on the basis of their 100% binding affinity towards all six HLA alleles, taken in this study. These peptides were further checked computationally to know their IFN-γ and IL4 inducing potential and nine peptides were identified. Peptide binding interactions with predominant HLA alleles were done by docking. Out of nine docked promiscuous peptides, only two peptides (QESRILRVIKKKLVR, RILRVIKKKLVRKTL), from LPG-3 and one peptide (FDKFWCLVIDALKRI) from NH showed lowest binding energy with all six alleles. These promiscuous T-cell epitopes were predicted on the basis of their antigenicity, hydrophobicity, potential immune response and docking scores. The immunogenicity of predicted promiscuous peptides might be used for subunit vaccine development with immune-modulating adjuvants.