Viral and bacterial respiratory tract co-infections in the same host often result in severity and heightened pathology of illness compared to single infections. This has proven to be true for combined infections with Influenza A virus and the bacterium Streptococcus pneumoniae. Separate vaccines do exist for each individual infection but they prove to be ineffective and non-specific when the infection has multiplied in case of co-infection. The study utilised in silico approaches and proposed a structural design for multi-epitope peptide vaccine having the ability to target co-infection caused by A/New York/392/2004 (H3N2) and R6 strains of Influenza A virus (NCBI Accession: PRJNA15622) and Streptococcus pneumoniae (NCBI Accession: PRJNA278), respectively. Epitope prediction followed by protein prioritization was performed using the reference sequence of each strain to short list the epitopes that can later be used for constructing multi-epitope structure. The multi-epitope constructs having Cholera Toxin Subunit B as adjuvant and (Gly4Ser)3 as flexible linker were then analyzed for their ability to induce an effective immune response in human body for which Macrophage receptor with collagenous structure, Toll-like receptor 2, 4 and 5 were taken as Pattern Recognition Receptors. The significant immune response generated through each Pattern Recognition Receptor helped to conclude that multi-epitope peptide structures can be used as probable candidates for the design of vaccine. The combination of the epitopes LWSYNAELL and FTGKQLQVG of Influenza A virus and Streptococcus pneumoniae, respectively, induced highly significant immune response in case of each Pattern Recognition Receptor when tested through in-silico predictive tools.
Pattern recognition receptor mediated downregulation of microRNA-650 fine-tunes MxA expression in dendritic cells infected with influenza A virus