Novel Cell-Penetrating Peptide-Based Vaccine Induces Robust CD4+ and CD8+ T Cell–Mediated Antitumor Immunity

Abstract

Vaccines that can coordinately induce multi-epitope T cellmediated immunity, T helper functions, and immunologic memory may offer effective tools for cancer immunotherapy. Here, we report the development of a new class of recombinant protein cancer vaccines that deliver different CD8 þ and CD4 þ T-cell epitopes presented by MHC class I and class II alleles, respectively. In these vaccines, the recombinant protein is fused with Z12, a novel cell-penetrating peptide that promotes efficient protein loading into the antigen-processing machinery of dendritic cells. Z12 elicited an integrated and multi-epitopic immune response with persistent effector T cells. Therapy with Z12-formulated vaccines prolonged survival in three robust tumor models, with the longest survival in an orthotopic model of aggressive brain cancer. Analysis of the tumor sites showed antigen-specific T-cell accumulation with favorable modulation of the balance of the immune infiltrate. Taken together, the results offered a preclinical proof of concept for the use of Z12-formulated vaccines as a versatile platform for the development of effective cancer vaccines. Cancer Res; 75(15);

Mechanistic insights into the efficacy of cell penetrating peptide-based cancer vaccines

“…2). This was directly demonstrated using Zebra-derived CPPs, TAT, and penetratin [16, 22, 24, 46, 54, 55]. …”

Enhancing Antitumor Immune Responses by Optimized Combinations of Cell-penetrating Peptide-based Vaccines and Adjuvants

“…25 We previously showed that a fusion protein combining ZEBRA CPP with epitope peptides was able to promote CD8 and CD4 T cell responses and antitumor control. 10 In this report, we identified the most efficacious CPP truncationsadjuvants combinations to elicit simultaneous CD8 and CD4 T cell immune responses for both model-and TAA-antigens.…”

“…We demonstrated that a fusion protein combining ZEBRA CPP with a multiantigenic protein was able to deliver multiepitope peptides to DCs, and subsequently to promote cytotoxic T lymphocyte (CTL) and Th cell activation, and antitumor function. 10 Here, we have identified truncations of ZEBRA CPP with different structural characteristics that markedly improve antigenspecific CD8 and CD4 T cell immune responses both in vitro and in vivo. Responses were assessed not only to the model antigen ovalbumin (OVA), but also to the human melanoma/melanocyte proteins gp100 and MART-1, and to tyrosinase related protein 2(Trp2).…”

“…10 To avoid the disulfide bridges during protein production and purification processes, the cysteine residue in Z12 was replaced by a serine residue in the variant Z13. Based on their theoretical isoelectric point (pI) and secondary structure, truncations were then designed from Z13 variant sequence.…”

“…9 We have previously demonstrated that the efficacy of protein-based vaccine delivery could be improved by the use of cell penetrating peptides (CPPs). 10 CPPs are peptides of residues that have the ability to cross the cell membrane and enter into most cell types. 11,12 The best described is the trans-activating transcriptional activator from the human immunodeficiency virus 1 (HIV-TAT), 13,14 but CPPs of different origins are now known.…”