Epitope vaccine design for Toxoplasma gondii based on a genome-wide database of membrane proteins

Parasit Vectors. 2022 Oct 12;15(1):364. doi: 10.1186/s13071-022-05497-z.

Abstract

Background: There is presently no effective and safe vaccine for Toxoplasma gondii for humans. The study described here was designed to search for a novel group of optimal B cell and T cell epitopes from Toxoplasma membrane proteins using genome-wide comprehensive screening.

Methods: The amino acid sequences of membrane proteins of T. gondii were obtained from the UniProt database. The ABCPred and BepiPred servers were employed to predict the linear B cell epitopes. The Immune Epitope Database (IEDB) online service was utilized to forecast T cell epitopes within T. gondii membrane proteins that bind to human leukocyte antigen (HLA) class I (HLA-I) or HLA-II molecules.

Results: From the 314 membrane proteins of T. gondii, a total of 14 linear B cell epitopes embedded in 12 membrane proteins were identified. Eight epitopes for major histocompatibility complex (MHC) class I (MHC-I) molecules and 18 epitopes for MHC-II molecules were ultimately selected, for which world population coverage percentiles were 71.94% and 99.76%, respectively. The top rated combinations of linear B cell epitopes and T cell epitopes covering both BALB/c mice and a majority of the human population were identified for the development of a protective vaccine.

Conclusions: The ultimate vaccine construct described here, which comprises B cells, MHC-I and MHC-II epitopes, might protect individuals against T. gondii infection by inducing humoral and cellular immune responses.

Keywords: Bioinformatics; Epitope vaccine; Human leukocyte antigen; Toxoplasma gondii.

MeSH terms

  • Animals
  • Epitopes, B-Lymphocyte / genetics
  • Epitopes, T-Lymphocyte / genetics
  • Histocompatibility Antigens Class II
  • Humans
  • Membrane Proteins / genetics
  • Mice
  • Mice, Inbred BALB C
  • Toxoplasma* / genetics
  • Vaccines*

Substances

  • Epitopes, B-Lymphocyte
  • Epitopes, T-Lymphocyte
  • Histocompatibility Antigens Class II
  • Membrane Proteins
  • Vaccines