In Silico Design and Immunologic Evaluation of HIV-1 p24-Nef Fusion Protein to Approach a Therapeutic Vaccine Candidate

摘要

Background: Acquired immune deficiency syndrome (HIV/AIDS) has been a majorglobal health concern for over 38 years. No safe and effective preventive or therapeutic vaccine hasbeen developed although many products have been investigated. Computational methods have facilitatedvaccine developments in recent decades. Among HIV-1 proteins, p24 and Nef are two suitabletargets to provoke the cellular immune response. However, the fusion form of these two proteinshas not been analyzed in silico yet.Objective: This study aimed at the evaluation of possible fusion forms of p24 and Nef in order toachieve a potential therapeutic subunit vaccine against HIV-1.Method: In this study, various computational approaches have been applied to predict the most effectivefusion form of p24-Nef including CTL (Cytotoxic T lymphocytes) response, immunogenicity,conservation and population coverage. Moreover, binding to MHC (Major histocompatibilitycomplex) molecules was assessed in both human and BALB/c.Results: After analyzing six possible fusion protein forms using AAY linker, we came up with themost practical form of p24 from 80 to 231 and Nef from 120 to 150 regions (according to their referencesequence of HXB2 strain) using an AAY linker, based on their peptides affinity to MHCmolecules which are located in a conserved region among different virus clades. The selected fusionprotein contains seventeen MHC I antigenic epitopes, among them KRWIILGLN, YKRWIILGL,DIAGTTSTL and FPDWQNYTP are fully conserved between the virus clades. Furthermore, analyzedclass I CTL epitopes showed greater affinity binding to HLA-B 57*01, HLA-B*51:01 andHLA-B 27*02 molecules. The population coverage with the rate of >70% coverage in the Persianpopulation supports this truncated form as an appropriate candidate against HIV-I virus.Conclusion: The predicted fusion protein, p24-AAY-Nef in a truncated form with a high rate of Tcell epitopes and high conservancy rate among different clades, provides a helpful model for developinga therapeutic vaccine candidate against HIV-1.