Investigating immune-modulatory function of α-glucopyranose-rich compound polysaccharides by MC38-N4/OT-I co-culture system.

The potential antitumor function of polysaccharides is well accepted, it is unclear whether polysaccharides have immunoregulatory effect on CD8+ T lymphocyte cells to attack tumor cells. To evaluate the CD8+ T function enhancing role of polysaccharide compounds, the MC38-N4/OT-I co-culture system was established. The synergistic and complementary immune effect of α-glucopyranose-rich compound polysaccharides can be achieved by manipulating the antigen-specific T-cell expansion capacity and efficacy. This study was designed to investigate the antitumor-enhancement activity of a α-glucopyranose-rich compound polysaccharides by determining the activation of CD8+ T cells in a co-culture system. Compared to the control group (42.5 % ±â€¯0.72 %), the specific α-glucopyranose-rich compound polysaccharides, comprising Agaricus blazei Murill, Grifola frondosa and Pericarpium Citri Reticulatae, demonstrated a significant decrease (20.4 % ±â€¯1.23 %, p < 0.05) in the survival rate of MC38-N4 cells in the co-culture system. Additionally, the α-glucopyranose-rich compound polysaccharides resulted in a substantial increase (p < 0.01) in the proportion of CD8+ T cells and CD62L+ central memory T cells, which is a less differentiated T cell subset with high immune activity. Collectively, we reported that specific polysaccharide combination, which remodel the function of cytotoxic T cells and provided a basis for improving immune functions by using the specific types of polysaccharides.

Paradoxical imbalance between activated lymphocyte protein synthesis capacity and rapid division rate.

Rapid lymphocyte cell division places enormous demands on the protein synthesis machinery. Flow cytometric measurement of puromycylated ribosome-associated nascent chains after treating cells or mice with translation initiation inhibitors reveals that ribosomes in resting lymphocytes in vitro and in vivo elongate at typical rates for mammalian cells. Intriguingly, elongation rates can be increased up to 30% by activation in vivo or fever temperature in vitro. Resting and activated lymphocytes possess abundant monosome populations, most of which actively translate in vivo, while in vitro, nearly all can be stalled prior to activation. Quantitating lymphocyte protein mass and ribosome count reveals a paradoxically high ratio of cellular protein to ribosomes insufficient to support their rapid in vivo division, suggesting that the activated lymphocyte proteome in vivo may be generated in an unusual manner. Our findings demonstrate the importance of a global understanding of protein synthesis in lymphocytes and other rapidly dividing immune cells.

OT-I TCR Transgenic Mice to Study the Role of PTPN22 in Anti-cancer Immunity.

Phosphotyrosine phosphatase non-receptor type 22 (PTPN22) is a key regulator of immune cell activation and responses. Genetic polymorphisms of PTPN22 have been strongly linked with an increased risk of developing autoimmune diseases, while analysis of PTPN22-deficient mouse strains has determined that PTPN22 serves as a negative regulator of T cell antigen receptor signaling. As well as these key roles in maintaining immune tolerance, PTPN22 acts as an intracellular checkpoint for T cell responses to cancer, suggesting that PTPN22 might be a useful target to improve T cell immunotherapies. To assess the potential for targeting PTPN22, we have crossed Ptpn22-deficient mice to an OT-I TCR transgenic background and used adoptive T cell transfer approaches in mouse cancer models. We provide basic methods for the in vitro expansion of effector OT-I cytotoxic T lymphocytes, in vitro phenotypic analysis, and in vivo adoptive T cell transfer models to assess the role of PTPN22 in anti-cancer immunity.