Immunoinformatics design of multi-epitope vaccine using surface cell antigen OmpB and heat shock protein GroEL against rickettsioses

Rickettsioses, caused by intracellular bacteria of the rickettsia genus, pose a global health threat, particularly affecting underserved communities. Delays in diagnosis and treatment due to limited healthcare access result in severe cases and fatalities. To address this, a multi-epitope vaccine targeting OmpB and GroEL proteins in epidemic and endemic typhus rickettsia was developed using immunoinformatics techniques. T-cell and B-cell epitopes were predicted from OmpB and GroEL proteins, resulting in 5 CTL, 4 HTL, and 4 B-cell epitopes. These epitopes were linked appropriately and combined with suitable adjuvants to construct the vaccine. The vaccine's physicochemical properties and tertiary structure were validated within acceptable ranges. Molecular docking analysis demonstrated favorable binding with TLR4 receptors and MHC molecules, further confirmed by molecular dynamics simulation. Immune simulation analysis predicted T-cell, IFN, and IL-2 responses upon vaccine administration. The vaccine sequence was then optimized and cloned into a plasmid vector pET-23a(+) at the Hind and AlwNI restriction sites. In this in silico experiment, a multi-epitope vaccine derived from OmpB and GroEL proteins is presented, the first validation steps of which have been completed. Subject to successful in vivo studies, this vaccine could prove to be a promising therapeutic strategy against rickettsiosis and address a critical public health challenge.