Both Immunization with Protein and Recombinant Vaccinia Virus Can Stimulate CTL Specific for the E7 Protein of Human Papilloma Virus 16 in H‐2^d Mice

Abstract

The transforming protein E7 of human papilloma virus type 16 can stimulate cytotoxic T lymphocytes (CTL) which can protect experimental animals against growth of E7 expressing tumour cells. In this study we compared CTL responses in mice immunized with either E7 protein in MF59 adjuvant or with recombinant vaccinia virus expressing E7 (Vac-E7). We have chosen H-2d mice because no E7-specific CTL responses have been described in this MHC haplotype. Immunization of these mice with Vac-E7 generated CTL which lysed target cells infected with Vac-E7 or transfected with the E7 gene. CTL from mice immunized with E7 protein in MF59 adjuvant showed specificity for the same target cells. Antibody blocking experiments revealed that both immunization with Vac-E7 and E7 protein stimulated CD8+ effector CTL. The find specificity of CTL induced by the two immunization protocols was similar. A major CTL epitope was mapped to the carboxyl terminal amino acids 48-98 of the E7 protein. Peptide isolation from E7 expressing cells followed by HPLC separation indicated that CTL induced by immunization with protein and Vac-E7 recognized the same HPLC purified peptide fractions. Together, the study suggests that vaccines based on protein can activate CTL with similar fine specificity to CTL induced by vaccines based on recombinant vaccinia virus.

Priming of cytotoxic T lymphocytes by five heat‐aggregated antigens in vivo: Conditions, efficiency, and relation to antibody responses

“…Instead, the CTL were specific for the Db-restricted epitope E7 49-57 [49, 521, possibly because of a tenfold higher surface expression of H-2 molecules as compared to A2Kb (W. Osen, unpublished data). In another study [53], efficient priming of E7-specific CTL in BALB/c mice was achieved by injection of heat-denatured E7 in combination with an adjuvant, MF59, whereas in our experiments, no adjuvant was used.…”

Recombinant Adeno-Associated Virus Expressing Human Papillomavirus Type 16 E7 Peptide DNA Fused with Heat Shock Protein DNA as a Potential Vaccine for Cervical Cancer

“…As described above, vaccination with E7 by different strategies can inhibit tumor growth (2,3,8,9,12,16,24,28,37,42). The response to tumor inhibition is mediated by CTLs.…”

“…Evidence for the value of HPV antigen-directed immunotherapy against cervical cancer comes from the experimental and natural papillomavirus-associated tumors that can be controlled by immunization with E7 antigen. Previous studies have used different modes of immunization, such as (i) recombinant E7 vaccinia viruses (2,3,16,24,28,42), (ii) syngeneic cells transfected with E7 (8,9), (iii) E7 proteinpulsed dendritic cells (12,37), (iv) peptides corresponding to a cytotoxic T-lymphocyte (CTL) epitope in E7 with incomplete Freund's adjuvant (13), (v) E7 vaccine based on papillomavirus-like particles (17,25,31), and (vi) Salmonella enterica serovar Typhimurium expressing E7 epitope inserted into hepatitis B virus core (26). These studies demonstrate that CTLs are likely to be the most effective immunological effector mechanisms.…”

The Effect of Human β2-Microglobulin on Major Histocompatibility Complex I Peptide Loading and the Engineering of a High Affinity Variant

“…These peptides are transported into the endoplasmic reticulum, where they are bound by MHC I⅐␤ 2 -microglobulin (␤ 2 m) complexes and finally transit to the cell surface (10 -12). Although this pathway is the dominant means of loading MHC I molecules, other methods of delivering antigenic peptides to MHC I have been described including direct incorporation of DNA into cells (13)(14)(15)(16), phagocytosis-dependent representation of antigens (17,18), and infection by bacterial (19) or viral vectors (20,21). All of these approaches attempt to introduce peptide into the endogenous loading pathway.…”