Toxoplasma gondii HLA-B(⁎)0702-restricted GRA7(20-28) peptide with adjuvants and a universal helper T cell epitope elicits CD8(+) T cells producing interferon-γ and reduces parasite burden in HLA-B(⁎)0702 mice

Hua Cong, Ernest J Mui, William H Witola, John Sidney, Jeff Alexander, Alessandro Sette, Ajesh Maewal, Kamal El Bissati, Ying Zhou, Yasuhiro Suzuki, Daniel Lee, Stuart Woods, Caroline Sommerville, Fiona Henriquez, Craig Roberts, Rima McLeod

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31 Citations (Scopus)


The ability of CD8(+) T cells to act as cytolytic effectors and produce interferon-γ (IFN-γ) was demonstrated to mediate resistance to Toxoplasma gondii in murine models because of the recognition of peptides restricted by murine major histocompatibility complex (MHC) class I molecules. However, no T gondii-specific HLA-B07-restricted peptides were proven protective against T gondii. Recently, 2 T gondii-specific HLA-B(⁎)0702-restricted T cell epitopes, GRA7(20-28) (LPQFATAAT) and GRA3(27-35) (VPFVVFLVA), displayed high-affinity binding to HLA-B(⁎)0702 and elicited IFN-γ from peripheral blood mononuclear cells of seropositive HLA-B(⁎)0702 persons. Herein, these peptides were evaluated to determine whether they could elicit IFN-γ in splenocytes of HLA-B(⁎)0702 transgenic mice when administered with adjuvants and protect against subsequent challenge. Peptide-specific IFN-γ-producing T cells were identified by enzyme-linked immunosorbent spot and proliferation assays utilizing splenic T lymphocytes from human lymphocyte antigen (HLA) transgenic mice. When HLA-B(⁎)0702 mice were immunized with one of the identified epitopes, GRA7(20-28) in conjunction with a universal CD4(+) T cell epitope (PADRE) and adjuvants (CD4(+) T cell adjuvant, GLA-SE, and TLR2 stimulatory Pam(2)Cys for CD8(+) T cells), this immunization induced CD8(+) T cells to produce IFN-γ and protected mice against high parasite burden when challenged with T gondii. This work demonstrates the feasibility of bioinformatics followed by an empiric approach based on HLA binding to test this biologic activity for identifying protective HLA-B(⁎)0702-restricted T gondii peptides and adjuvants that elicit protective immune responses in HLA-B(⁎)0702 mice.
Original languageEnglish
Pages (from-to)1-10
Number of pages10
JournalHuman Immunology
Issue number1
Publication statusPublished - Jan 2012


  • toxoplasma gondii
  • vaccine
  • adjuvant
  • epitopes

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