Mini-TCRs: Truncated T cell receptors to generate T cells from induced pluripotent stem cells

Allogeneic T cell platforms utilizing induced pluripotent stem cell (iPSC) technology exhibit significant promise for the facilitation of adoptive immunotherapies. While mature T cell receptor (TCR) signaling plays a crucial role in generating T cells from iPSCs, the introduction of exogenous mature TCR genes carries a potential risk of causing graft-versus-host disease (GvHD). In this study, we present the development of truncated TCRα and TCRβ chains, termed mini-TCRs, which lack variable domains responsible for recognizing human leukocyte antigen (HLA)-peptide complexes. We successfully induced cytotoxic T lymphocytes (CTLs) from iPSCs by employing mini-TCRs. Combinations of TCRα and TCRβ fragments were screened from mini-TCR libraries based on the surface localization of CD3 proteins and their ability to transduce T cell signaling. Consequently, mini-TCR-expressing iPSCs underwent physiological T cell development, progressing from the CD4 and CD8 double-positive stage to the CD8 single-positive stage. The resulting iPSC-derived CTLs exhibited comparable cytokine production and cytotoxicity in comparison to that of full-length TCR-expressing T lymphocytes when chimeric antigen receptors (CARs) were expressed. These findings demonstrate the potential of mini-TCR-carrying iPSCs as a versatile platform for CAR T cell therapy, offering a promising avenue for advancing adoptive immunotherapies.

Generation of HIV-Resistant Macrophages from IPSCs by Using Transcriptional Gene Silencing and Promoter-Targeted RNA

Highly active antiretroviral therapy (HAART) has markedly prolonged the prognosis of HIV-1 patients. However, lifelong dependency on HAART is a continuing challenge, and an effective therapeutic is much desired. Recently, introduction of short hairpin RNA (shRNA) targeting the HIV-1 promoter was found to suppress HIV-1 replication via transcriptional gene silencing (TGS). The technology is expected to be applied with hemato-lymphopoietic cell transplantation of HIV patients to suppress HIV transcription in transplanted hemato-lymphopoietic cells. Combination of the TGS technology with new cell transplantation strategy with induced pluripotent stem cell (iPSC)-derived hemato-lymphopoietic cells might contribute to new gene therapy in the HIV field. In this study, we evaluated iPSC-derived macrophage functions and feasibility of TGS technology in macrophages. Human iPSCs were transduced with shRNAs targeting the HIV-1 promoter region (shPromA) by using a lentiviral vector. The shPromA-transfected iPSCs were successfully differentiated into functional macrophages, and they exhibited strong protection against HIV-1 replication with alteration in the histone structure of the HIV-1 promoter region to induce heterochromatin formation. These results indicated that iPS-derived macrophage is a useful tool to investigate HIV infection and protection, and that the TGS technology targeting the HIV promoter is a potential candidate of new gene therapy.

Intraabdominal bleeding attributed to ruptured periumbilical varices. A case report and a review of the literature

A 50 year old man, who had had liver cirrhosis of 10 years, without previous variceal bleeding, presented with sudden abdominal pain, distension and hypotension and was admitted. The diagnosis of ruptured periumbilical varices was established at laparotomy. Despite surgical intervention to halt the bleeding varices the patient died of hepatic failure fourteen days postoperatively. The differential diagnosis and management of hemoperitoneum in this cirrhotic patient are discussed, and sixteen previously reported cases of intraabdominal variceal bleeding are reviewed.