RESUMO
Engineering T cells with chimeric antigen receptors (CARs) is an effective method for directing T cells to attack tumors, but may cause adverse side effects such as the potentially lethal cytokine release syndrome. Here the authors show that the T cell antigen coupler (TAC), a chimeric receptor that co-opts the endogenous TCR, induces more efficient anti-tumor responses and reduced toxicity when compared with past-generation CARs. TAC-engineered T cells induce robust and antigen-specific cytokine production and cytotoxicity in vitro, and strong anti-tumor activity in a variety of xenograft models including solid and liquid tumors. In a solid tumor model, TAC-T cells outperform CD28-based CAR-T cells with increased anti-tumor efficacy, reduced toxicity, and faster tumor infiltration. Intratumoral TAC-T cells are enriched for Ki-67+ CD8+ T cells, demonstrating local expansion. These results indicate that TAC-T cells may have a superior therapeutic index relative to CAR-T cells.
Assuntos
Receptores de Antígenos/imunologia , Receptores de Antígenos Quiméricos/imunologia , Proteínas Recombinantes/imunologia , Especificidade do Receptor de Antígeno de Linfócitos T/imunologia , Linfócitos T/imunologia , Transferência Adotiva , Animais , Antígenos CD28/imunologia , Linhagem Celular Tumoral , Citocinas/sangue , Citocinas/metabolismo , Citotoxicidade Imunológica , Feminino , Engenharia Genética , Células HEK293 , Humanos , Imunoterapia Adotiva/métodos , Lentivirus/genética , Ativação Linfocitária , Masculino , Camundongos , Camundongos Endogâmicos NOD , Engenharia de Proteínas , Receptor ErbB-2/imunologia , Receptores de Antígenos/genética , Receptores de Antígenos Quiméricos/genética , Anticorpos de Domínio Único , Especificidade do Receptor de Antígeno de Linfócitos T/genética , Linfócitos T Citotóxicos/imunologia , Visão Ocular , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
BACKGROUND: Chlamydia spp. are believed to use a conserved virulence factor called type III secretion (T3S) to facilitate the delivery of effector proteins from the bacterial pathogen to the host cell. Important early effector proteins of the type III secretion system (T3SS) are a class of proteins called the translocators. The translocator proteins insert into the host cell membrane to form a pore, allowing the injectisome to dock onto the host cell to facilitate translocation of effectors. CopB is a predicted hydrophobic translocator protein within the chlamydial T3SS. RESULTS: In this study, we identified a novel interaction between the hydrophobic translocator, CopB, and the putative filament protein, CdsF. Furthermore, we identified a conserved PxLxxP motif in CopB (amino acid residues 166-171), which is required for interaction with its cognate chaperone, LcrH_1. Using a synthetic peptide derived from the chaperone binding motif of CopB, we were able to block the LcrH_1 interaction with either CopB or CopD; this CopB peptide was capable of inhibiting C. pneumoniae infection of HeLa cells at micromolar concentrations. An antibody raised against the N-terminus of CopB was able to inhibit C. pneumoniae infection of HeLa cells. CONCLUSION: The inhibition of the LcrH_1:CopB interaction with a cognate peptide and subsequent inhibition of host cell infection provides strong evidence that T3S is an essential virulence factor for chlamydial infection and pathogenesis. Together, these results support that CopB plays the role of a hydrophobic translocator.