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Orientia tsutsugamushi, a cause of scrub typhus is emerging as an important pathogen in several parts of the tropics. The control of this infection relies on rapid diagnosis, specific treatment, and prevention through vector control. Development of a vaccine for human use would be very important as a public health measure. Antibody and T‐cell response have been found to be important in the protection against scrub typhus. This study was undertaken to predict the peptide vaccine that elicits both B‐ and T‐cell immunity. The outer‐membrane protein, 47‐kDa high‐temperature requirement A was used as the target protein for the identification of protective antigen(s). Using BepiPred2 program, the potential B‐cell epitope PNSSWGRYGLKMGLR with high conservation among O. tsutsugamushi and the maximum surface exposed residues was identified. Using IEDB, NetMHCpan, and NetCTL programs, T‐cell epitopes MLNELTPEL and VTNGIISSK were identified. These peptides were found to have promiscuous class‐I major histocompatibility complex (MHC) binding affinity to MHC supertypes and high proteasomal cleavage, transporter associated with antigen processing prediction, and antigenicity scores. In the I‐TASSER generated model, the C‐score was −0.69 and the estimated TM‐score was 0.63 ± 0.14. The location of the epitope in the 3D model was external. Therefore, an antibody to this outer‐membrane protein epitope could opsonize the bacterium for clearance by the reticuloendothelial system. The T‐cell epitopes would generate T‐helper function. The B‐cell epitope(s) identified could be evaluated as antigen(s) in immunodiagnostic assays. This cocktail of three peptides would elicit both B‐ and T‐cell immune response with a suitable adjuvant and serve as a vaccine candidate.

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Introduction: The Rubella virus has a worldwide occurrence and congenital Rubella syndromes are widely recognized as an emerging infection in several parts of the world. Miscarriage, perinatal mortality, and stillbirth can develop in pregnancy during the first trimester. The most frequent techniques for laboratory diagnosis of Rubella virus infection are IgM and IgG-based serological detection methods. Such emerging viral and bacterial pathogen emphasizes the development of fast diagnostic devices; there is a need for enhanced and quicker methods. Materials and Methods: Search for peptide vaccine with specific T and B-cell epitopes was identified through bioinformatics-based approaches. These were identified utilizing available Rubella virus E1 glycoprotein sequence databases. The outer-membrane glycoprotein, E1 is a target protein for the prediction of best antigens. Results: Using BepiPred2 program, the potential B-cell epitope PFCNTPHGQLEVQVPPDPGD    with high conservation among E1 glycoprotein of rubella virus and the maximum surface exposed residues was identified.  Using IEDB, NetMHCpan, and NetCTL programs, T-cell epitope RPVALPRAL was identified. Predicted epitopes were found to have promiscuous class-I major histocompatibility complex binding affinity to major histocompatibility complex super types, antigenicity scores, and high proteasomal cleavage. The three-dimensional modeled structures were created using I-TASSER online server for highlighting the predicted T- and B- cell epitopes. Conclusion: The predicted T and B cell epitope could be used for the development of immunoglobulin assay and vaccine candidate peptide.