Inferring Toll-Like Receptor induced epitope subunit vaccine candidate against SARS-CoV-2: A Reverse Vaccinology approach

Toll-Like Receptors (TLRs) are a group of Pattern Recognition Receptors (PRRs) which bind to the exogenous pathogen associated molecular patterns (PAMPs) like other PRRs; hence the main function is to sense the harmness and mediate the innate immune response to pathogens. TLRs play an important role in innate immune responses to infection. The host has evolved to use other TLR and PAMP agonists as agents to stimulate a protective inflammatory immune response against infection. Because only a small number of doses are given, TLR agonists appear to have greater potential and fewer safety concerns than other uses as vaccine adjuvants. In the present days, development of peptides targeting immune response can be approved for survival in biological monitoring systems before vaccine exposures. Peptide vaccines are easy to synthesize, more stable and relatively safe. In addition, production of peptides becomes simple, easily reproducible, fast and cost effective. Getting vaccinated against Covid-19, which has become a pandemic in the human population, is the most practical way to control the outbreak. The new coronavirus does not contain a drug or vaccine to prevent it from spreading to humans. To getting a proper vaccine candidate against the novel coronavirus, the present study used the reverse vaccinology approach by using a complete set of SARS-CoV-2 proteins; such as: Spike, Envelope, Nucleocapsid, Membrane, NSPs, and ORFs to extract the antigenic elements that produce B-cell, T-cell and IFN positive epitopes. These epitopes with precise binding to the Toll-Like receptors (1-10) have developed epitope based vaccine candidates. We have prioritized a set of epitopes based on their antigenicity, allergenicity, sequence conservation and projected population coverage world-wide. The selected epitopes were employed for in-silico docking interactions with Toll-Like receptors and molecular dynamic simulation confirmed the stability of the vaccine candidates resulting epitope of spike proteins with both the TLR 7 and 8 shows the best binding affinity. We believe that this ideal epitope vaccine candidate could enhance the immune response of the host and reduce the reinfection risk.