Characterization of B cell-mediated PD-1/PD-L1 interaction in pancreatic cancer patients.

Pancreatic ductal adenocarcinoma (PDAC) is a common type of pancreatic cancer with one of the worst survival rate of all malignancies. Recent studies have identified that immunosuppressive B cells could employ the PD-1/PD-L1 pathway to suppress antitumour T cell responses; hence, we examined the expression and function of PD-L1 in B cells. We found that the PD-L1 expression was significantly enriched in tumour-infiltrating (TI) B cells than in peripheral blood (PB) B cells from the same patients. Additionally, the PB B cells from stage III and stage IV PDAC patients presented significantly higher PD-L1 than the PB B cells from healthy controls. High PD-L1 expression in PB B cells could be achieved by stimulation via CpG and less effectively via anti-BCR plus CD40L, but not by coculture with pancreatic cancer cell lines in vitro. Also, STAT1 and STAT3 inhibition significantly suppressed PD-L1 upregulation in stimulated B cells. CpG-stimulated PB B cells could inhibit the IFN-γ expression and proliferation of CD8 T cells in a PD-L1-dependent manner. Also, TI CD8 T cells incubated with whole TI B cells presented significantly lower IFN-γ expression and lower proliferation, than TI CD8 T cells incubated with PD-L1+  cell-depleted TI B cells, suggesting that PD-L1+  B cells could also suppress CD8 T cells in the tumour. Overall, this study identified that B cells could suppress CD8 T cells via PD-L1 expression, indicating a novel pathway of immuno-regulation in pancreatic cancer.

[Impacts of climate change on maize potential productivity in Northeast China and the simulation of control measures: A case study of Jilin Province, China]. / 气候变化对东北地区玉米生产潜力的影响与调控措施模拟­­ä»¥å‰æž—省为例.

In this study, we collected data of meteorology, soil property, agricultural management and corn yield from five representative sites in Jilin Province, China, and integrated these data into a crop growth model of CERES-maize to simulate the potential productivity of five corn varieties. Our objectives were to simulate, calibrate and validate genetic parameters of the corns based on the analyses of climatic effects on the productivity, and to establish best practices for enhancing crop production in response to climatic change. The results showed that the projected days of sowing-flo-wering and flowering-maturing stages and yields of corn were well consistent with the measured va-lues with normalized mean variances being 2.96%, 3.40% and 9.37%, respectively, and the stan-dard deviation ranged from -10.6% to 15.2%. The mean projected light-temperature potential productivity (LTPP) of corns ranged from 7799.60 to 12902.83 kg·hm-2·a-1, which decreased by 128.6-880.3 kg·hm-2 every 10 years. The correlation analysis suggested that climate change, i.e. temperature rising and significant decline of total radiation during the growth of corns, dominated the decrease of LTPP of corns in the region. The simulated genetic parameters indicated that the LTPP of the corns increased linearly with the increase of P5 (filling stage characteristic parameter referred to silking to physiological maturity of more than 8 ℃ heat time). Our model estimated that the LTPP might increase 154.44-261.10 kg·hm-2 for every 10 ℃·d increase of P5. The simulated sowing date delay showed that five days' sowing delay would maximize the LTPP of corns in Dunhua and Liaoyuan with 0.47% and 1.32% increase, respectively, while 15 days' delay would maximize the LTPP in Huadian and Yushu with 1.10% and 4.06% increase, respectively.