Combating Streptococcus agalactiae infections by designing a multi-epitope vaccine using molecular dynamic simulations.

AIM: To construct a multi-epitope vaccine using virulent proteins of Streptococcus agalactiae strain 2603 V/R.

BACKGROUND

Streptococcus agalactiae strain 2603 V/R is causative agent of various diseases and infections in neonates, pregnant women as well as elderly patients with significant underlying diseases. World health organisation reported high number of new born deaths and stillbirths. Various studies have shown that no licensed vaccine is available against meningitis caused by GBS. Therefore, new preventive methods against GBS are desirable to be developed.

OBJECTIVES

1. To identify antigenic proteins from proteome of Streptococcus agalactiae 2603 V/R. 2. Identification of epitopes from filtered-out proteins. 3. Designing a multi-epitope vaccine using epitopes of screened proteins and validating it with docking analysis and simulation studies.

METHODS

The proteins of pathogen Streptococcus agalactiae strain 2603 V/R were analysed to obtain antigenic proteins which were further used for B and T cell epitope predictions using various reverse vaccinology-based tools. Finally, by applying immunoinformatics approach a MEV construct was designed. Molecular docking analysis was performed for better understanding of binding energy and further validation was done using molecular dynamic simulations.

RESULTS

4 target proteins were screened for construction of MEV using 27 predicted epitopes and docking analysis demonstrated vaccine interaction with TLR, MHC I and MHC II having binding energy -40.862 kcal/mol, -43.866 kcal/mol and -56.942 kcal/mol. Simulation studies demonstrated that the vaccine complexed with immune and MHC receptors was stable during the simulation time.

CONCLUSIONS

The isolated virulent proteins provided insights into crucial targets for development of an efficient, highly specific, and safe MEV construct. The anticipated vaccine construct will potentially provide a long-term immunity to majority of people against Streptococcus agalactiae.