Cytotoxic T lymphocytes raised against a subdominant epitope offered as a synthetic peptide eradicate human papillomavirus type 16‐induced tumors

Abstract

Cytotoxic T lymphocytes raised against a subdominanl epitope offered as a synthetic peptide eradicate human papillomavirus type 16-induced tumorsPreviously, we have shown that immunization with human papillomavirus (HPV) type 16-derived cytotoxic T lymphocyte (CTL) epitope E7 <W-57 (RAHYNIVTF) renders C?7BL/6mice insensitive to tumors formed hy HPV16-transformed cells. In this study, we provide evidence that E7 49-57 is expressed as a subdominanl CTL epitope on HPVI6-transformed C57BL/6 cells. Using acid peptide cliilion, it is shown that HPV16-transformed tells express another CTL epitope. besides E7 49-57, which appears to he dominant. We demonstrate that a CTL line raised against the subdominant CTL epitope. offered as synthetic peptide E7 49-57, eradicates established. HPV16-mduced tumors in mice. Our data show that synthetic peptide-induced CTL can be applied successfully in vivo against (virus-induced) tumor, and emphasize thai subdominant CTL epitopes are useful targets for immunothcrapy. Furthermore, it is illustrated for the first time that HPV In-specific CTL interfere directly with HPVIft-indueed tumors. IntroductionHuman papillomavirus (HPV) type 16, in particular the Viral oncogene products E6 and È7, arc believed to piuy a causative role in cervical cancer flj, Development of HPV16-associated (pre)malignant lesions is enhanced in individuals with impaired T ceJI responses J2-5J, suggesting that cellular immunity impedes HPV Ift-associated tumor development, CTL are important effectors of protection against (virus-induced) cancer [6, 7|. They lyse target cells upon recognition of specific peptides presented at the cell surface by MHC class 1 molecules |8j. In the case of virus-infected cefls, these peptides originate mainly from rntraceJlular viral proteins [9, 10J, which are degraded in the cylosol and bound specificaMy by class I MHC molecules, followed by transport to the cell surface [11]. [12], presumably as the result of specific recognition of peptide E7 49-57 presented by class t MHC H-2D" molecules on the tumor cell membrane. Therefore, CTL raised against synthetic peptide E749-57 should be'able to rccogni/e naturally processed E7 49-57 peptide expressed: on HPV 16-transformed C3 cells and cure established C3 tumors when injected in tumorbeartng B6 mice.In this study, we describe ïhe generation and characterization of a stable CTL line raised against synthetic peplidc E7 49-57. This CTL line specifically recognizes E7 4^-57 as a naturally processed peptide on HPV]6-transf:>nned C3 ce3ls and eradicates established O tumors in Bn nude mice, in addition, we show that OTL epitope E7 49-57 is immuno-subdominantJy expressed on C3 cells, inasmuch as CTL raised against C3 cells recognize another naluralK' processed; peptide. The data prestrnled in this study are the first esampJes of CTL-based immunotherapy against established HPVI6-induced tumors, supporting the thought that T cells are involved in the control of cervical cancer. Furthermore, our data stress the feasibility of generating tumor-sp...

LPD lipopolyplex initiates a potent cytokine response and inhibits tumor growth

“…In contrast, the tumor models utilized in this study are at least mildly immunogenic (24JK-FBP) or known to be highly immunogenic (C3). 33,34,35 Although the 24JK-FBP line was derived by retroviral transfection of human folate-binding protein into the lowly immunogenic 24JK parental line, 36 the immunogenicity of the resultant 24JK-FBP line is not known. However, the immunogenicity of 24JK-FBP is almost certain to be increased, compared with the parental line, due to stable integration of the retroviral genes and human FBP.…”

Immunization strategy against cervical cancer involving an alphavirus vector expressing high levels of a stable fusion protein of human papillomavirus 16 E6 and E7

“…2,3 HPV E6 and E7 proteins, constitutively expressed in HPV-transformed cells, are considered to be tumor-specific antigens that can act as targets for cytotoxic T lymphocyte (CTL)-mediated tumor cell killing and stimulation of tumor-specific CTL activity. [4][5][6][7] The induction of class I MHC-restricted CTL activity is optimally achieved by synthesis of viral antigens within antigen presenting cells (APCs), for example through immunization with live attenuated virus. However, apart from its potential risk, this is at present not an option for immunization against HPV infection since the virus cannot be successfully propagated to yield virus particles.…”

Genetic immunization against cervical carcinoma: induction of cytotoxic T lymphocyte activity with a recombinant alphavirus vector expressing human papillomavirus type 16 E6 and E7

“…[10][11][12] Major drawbacks associated with a peptidebased approach include the problem of MHC polymorphism and the risk of inducing T cell tolerance rather than T cell activation. Due to the induction of specific T cell tolerance, vaccination with a tumor-specific peptide…”

“…7,8 In several animal models it has been demonstrated that the HPV E6 and E7 proteins, constitutively expressed in HPV-transformed cells, can act as targets for CTL-mediated tumor cell killing and stimulation of tumor-specific CTL activity. [9][10][11][12] Induction of an antigen-specific CTL response requires intracellular processing of the target antigen and presentation of antigenic peptides by MHC class I molecules. This can be achieved efficiently with recombinant viral vectors.…”