Analysis of the T-cell receptor (TCR) repertoire of innate CD4+ T cells selected by major histocompatibility complex (MHC) class II-dependent thymocyte-thymocyte (T-T) interaction (T-T CD4+ T cells) is essential for predicting the characteristics of the antigens that bind to these T cells and for distinguishing T-T CD4+ T cells from other types of innate T cells. Using the TCRmini Tg mouse model, we show that the repertoire of TCRalpha chains in T-T CD4+ T cells was extremely diverse, in contrast to the repertoires previously described for other types of innate T cells. The TCRalpha chain sequences significantly overlapped between T-T CD4+ T cells and conventional CD4+ T cells in the thymus and spleen. However, the diversity of the TCRalpha repertoire of T-T CD4+ T cells seemed to be restricted compared with that of conventional CD4+ T cells. Interestingly, the frequency of the parental OT-II TCRalpha chains was significantly reduced in the process of T-T interaction. This diverse and shifted repertoire in T-T CD4+ T cells has biological relevance in terms of defense against diverse pathogens and a possible regulatory role during peripheral T-T interaction.
Amino Acid Sequence ; Animals ; Antigens, Surface/metabolism ; CD4-Positive T-Lymphocytes/cytology/*immunology/*metabolism ; Cell Communication ; Cell Differentiation/genetics/immunology ; Clonal Evolution ; Histocompatibility Antigens Class II/*immunology ; *Immunity, Innate ; Immunophenotyping ; Lymphocyte Count ; Mice ; Mice, Knockout ; Mice, Transgenic ; Peptide Fragments/chemistry ; Phenotype ; Receptors, Antigen, T-Cell/chemistry/*genetics/metabolism ; Receptors, Antigen, T-Cell, alpha-beta/chemistry/genetics ; Spleen/cytology ; Thymocytes/cytology/immunology/metabolism

Chimeric antigen receptor (CAR) T cell therapy is a promising cancer treatment that has recently been undergoing rapid development. However, there are still some major challenges, including precise tumor targeting to avoid off-target or "on-target/off-tumor" toxicity, adequate T cell infiltration and migration to solid tumors and T cell proliferation and persistence across the physical and biochemical barriers of solid tumors. In this review, we focus on the primary challenges and strategies to design safe and effective CAR T cells, including using novel cutting-edge technologies for CAR and vector designs to increase both the safety and efficacy, further T cell modification to overcome the tumor-associated immune suppression, and using gene editing technologies to generate universal CAR T cells. All these efforts promote the development and evolution of CAR T cell therapy and move toward our ultimate goal-curing cancer with high safety, high efficacy, and low cost.
Cell Movement ; immunology ; Cell Proliferation ; Gene Expression ; Genetic Vectors ; chemistry ; metabolism ; Humans ; Immunotherapy, Adoptive ; methods ; Lymphocyte Activation ; Lymphocytes, Tumor-Infiltrating ; cytology ; immunology ; transplantation ; Neoplasms ; genetics ; immunology ; pathology ; therapy ; Patient Safety ; Receptors, Antigen, T-Cell ; chemistry ; genetics ; immunology ; Recombinant Fusion Proteins ; chemistry ; genetics ; immunology ; Signal Transduction ; Single-Chain Antibodies ; chemistry ; genetics ; T-Lymphocytes ; cytology ; immunology ; transplantation ; Treatment Outcome