RESUMO
The ultimate success of cancer vaccination is dependent upon the generation of tumor-specific CTLs. In this study, we designed and evaluated a novel fusion protein comprising a cell penetrating and immunostimulatory peptide corresponding to residues 32-51 of the Limulus polyphemus protein (LALF(32-51)) linked to human papillomavirus (HPV) 16 E7 antigen (LALF(32-51)-E7). We demonstrated that LALF(32-51) penetrates the cell membrane and delivers E7 into cells. In a preclinical model of HPV16-induced cervical carcinoma we showed that vaccination with adjuvant-free LALF(32-51)-E7 fusion protein significantly improves the presentation of E7-derived peptides to T-cells in vitro and induces suppression of tumor growth.
Assuntos
Carcinoma/prevenção & controle , Caranguejos Ferradura/imunologia , Papillomavirus Humano 16/imunologia , Proteínas E7 de Papillomavirus/imunologia , Infecções por Papillomavirus/prevenção & controle , Vacinas contra Papillomavirus/imunologia , Neoplasias do Colo do Útero/prevenção & controle , Animais , Carcinoma/imunologia , Modelos Animais de Doenças , Feminino , Caranguejos Ferradura/genética , Papillomavirus Humano 16/genética , Camundongos , Camundongos Endogâmicos C57BL , Proteínas E7 de Papillomavirus/administração & dosagem , Proteínas E7 de Papillomavirus/genética , Infecções por Papillomavirus/imunologia , Vacinas contra Papillomavirus/administração & dosagem , Vacinas contra Papillomavirus/genética , Proteínas Recombinantes de Fusão/administração & dosagem , Proteínas Recombinantes de Fusão/imunologia , Neoplasias do Colo do Útero/imunologiaRESUMO
Previous studies have shown that cyclic peptides corresponding to residues 35 to 52 of the Limulus antilipopolysaccharide (anti-LPS) factor (LALF) bind and neutralize LPS-mediated in vitro and in vivo activities. Therapeutic approaches based on agents which bind and neutralize LPS activities are particularly attractive because these substances directly block the primary stimulus for the entire proinflammatory cytokine cascade. Here we describe new activities of the LALF(31-52) peptide, other than its LPS binding ability. Surprisingly, supernatants from human mononuclear cells stimulated with the LALF peptide are able to induce in vitro antiviral effects on the Hep-2 cell line mediated by gamma interferon (IFN-gamma) and IFN-alpha. Analysis of the effect of LALF(31-52) on tumor necrosis factor (TNF) and nitric oxide (NO) production by LPS-stimulated peritoneal macrophages revealed that a pretreatment with the peptide decreased LPS-induced TNF production but did not affect NO generation. This indicates that the LALF peptide modifies the LPS-induced response. In a model in mice with peritoneal fulminating sepsis, LALF(31-52) protected the mice when administered prophylactically, and this effect is related to reduced systemic TNF-alpha levels. This study demonstrates, for the first time, the anti-inflammatory properties of the LALF-derived peptide. These properties widen the spectrum of the therapeutic potential for this LALF-derived peptide and the molecules derived from it. These agents may be useful in the prophylaxis and therapy of viral and bacterial infectious diseases, as well as for septic shock.