Preferential amplification of a human mitochondrial DNA deletion in vitro and in vivo.

We generated induced pluripotent stem cells (iPSCs) from patient fibroblasts to yield cell lines containing varying degrees of heteroplasmy for a m.13514 A > G mtDNA point mutation (2 lines) and for a ~6 kb single, large scale mtDNA deletion (3 lines). Long term culture of the iPSCs containing a single, large-scale mtDNA deletion showed consistent increase in mtDNA deletion levels with time.

Stendomycin selectively inhibits TIM23-dependent mitochondrial protein import.

Tim17 and Tim23 are the main subunits of the TIM23 complex, one of the two major essential mitochondrial inner-membrane protein translocon machineries (TIMs). No chemical probes that specifically inhibit TIM23-dependent protein import were known to exist. Here we show that the natural product stendomycin, produced by Streptomyces hygroscopicus, is a potent and specific inhibitor of the TIM23 complex in yeast and mammalian cells.

Low TCR avidity and lack of tumor cell recognition in CD8(+) T cells primed with the CEA-analogue CAP1-6D peptide.

The use of "altered peptide ligands" (APL), epitopes designed for exerting increased immunogenicity as compared with native determinants, represents nowadays one of the most utilized strategies for overcoming immune tolerance to self-antigens and boosting anti-tumor T cell-mediated immune responses. However, the actual ability of APL-primed T cells to cross-recognize natural epitopes expressed by tumor cells remains a crucial concern. In the present study, we show that CAP1-6D, a superagonist analogue of a carcinoembriyonic antigen (CEA)-derived HLA-A*0201-restricted epitope widely used in clinical setting, reproducibly promotes the generation of low-affinity CD8(+) T cells lacking the ability to recognized CEA-expressing colorectal carcinoma (CRC) cells.

CD8+ T-cell tolerance can be broken by an adenoviral vaccine while CD4+ T-cell tolerance is broken by additional co-administration of a Toll-like receptor ligand.

T-cell tolerance to tumor antigens is a considerable challenge to cancer immunotherapy. The existence of a murine model transgenic for human carcinoembryonic antigen (CEA) allows CEA vaccination efficacy to be studied in a physiologically tolerant context. Immunization of CEA-transgenic mice with an adenoviral vector coding for CEA induced a significant CD8+ T-cell response specific to CEA but failed to induce CEA-specific CD4+ T cells and antibodies.