B7家族成员反向信号调控的研究进展

共刺激分子免疫球蛋白家族—B7家族成员与CD28家族成员之间相互作用向T细胞传递共刺激信号,在T细胞充分活化和功能发挥中发挥了重要的功能。近几年研究表明,部分B7家族成员向T细胞传递免疫信号的同时,也向表达B7分子的抗原提呈细胞传递反向信号,增强或抑制了抗原提呈细胞的功能,并进一步在维持T细胞免疫和T细胞耐受中发挥重要的功能。     

Effects of anesthesia-induced modest hypothermia on cellular radiation sensitivity

To assess the mechanisms of modest hypothermia (MH) and its effects on cellular radiation response, a model of anesthesia-induced modest hypothermia (AIMH) in the adult mice and a model of pure MH in the newborn mice were established. The survival rate of lethally irradiated mice was increased to 72% through AIMH before irradiation. Both apoptosis and necrosis of human fetal bone marrow CD34+ hematopoietic stem cells cultured under MH were significantly decreased as detected by MTT and flow cytometry, with three-color labeled by PE-CD34+/ FITC-AnnexinV /7AAD. The survival and proliferation of mouse bone marrow MNC treated with MH after irradiation were also increased. The MH exerted similar protective effects on the leukemia cell lines A20, HL60, K562 to the normal bone marrow cells, but it enhanced the radiation sensitivity of leukemia cell line FBL3 and mouse melanoma B16F10. No effects have been found on the radiation sensitivity of those cells treated with MH before irradiation. The results also show     

B7家族成员反向信号调控的研究进展

共刺激分子免疫球蛋白家族-B7家族成员与CD28家族成员之间相互作用向T细胞传递共刺激信号,在T细胞充分活化和功能发挥中发挥了重要的功能.近几年研究表明,部分B7家族成员向T细胞传递免疫信号的同时,也向表达B7分子的抗原提呈细胞传递反向信号,增强或抑制了抗原提呈细胞的功能,并进一步在维持T细胞免疫和T细胞耐受中发挥重要的功能.     

麻醉诱导中度低温对辐射敏感性的影响

为探讨中度低温对辐射敏感性的影响及其机制,分别建立了正常成年小鼠和新生小鼠30℃中度低温模型,表明照射前麻醉诱导中度低温能提高小鼠存活率达72%(P＜0.001);流式细胞术三色荧光法和MTT法检测结果表明,正常骨髓单个核细胞和CD₃₄⁺造血干(祖)细胞在受照射后经中度低温处理后,凋亡和死亡细胞数量减少;对受照射后的白血病细胞系A20,HL60,K562和实体瘤3LL,LOVO中度低温也有相似的保护作用,但是对小鼠白血病FBL3细胞系、小鼠实体瘤B16,F10和CT26却提高其辐射敏感性.结果提示,中度低温对不同组织细胞的辐射敏感性的作用是不同的;低温和麻醉有协同作用;中度低温对正常骨髓CD₃₄⁺造血干(祖)细胞能减少辐射所致的细胞凋亡和死亡,但是对某些白血病细胞和实体瘤细胞却增加了辐射敏感性,这就有可能通过麻醉诱导中度低温以增强放疗效果并减轻毒副作用,有临床运用潜力,同时也提示除低温所致低氧效应外,存在低温诱导性因子的可能性.     

Effects of anesthesia-induced modest hypothermia on cellular radiation sensitivity

To assess the mechanisms of modest hypothermia (MH) and its effects on cellular radiation response, a model of anesthesia-induced modest hypothermia (AIMH) in the adult mice and a model of pure MH in the newborn mice were established. The survival rate of lethally irradiated mice was increased to 72% through AIMH before irradiation. Both apoptosis and necrosis of human fetal bone marrow CD34⁺ hematopoietic stem cells cultured under MH were significantly decreased as detected by MTT and flow cytometry, with three-color labeled by PE-CD₃₄ ⁺/ FITC-AnnexinV /7AAD. The survival and proliferation of mouse bone marrow MNC treated with MH after irradiation were also increased. The MH exerted similar protective effects on the leukemia cell lines A20, HL60, K562 to the normal bone marrow cells, but it enhanced the radiation sensitivity of leukemia cell line FBL3 and mouse melanoma B16F10. No effects have been found on the radiation sensitivity of those cells treated with MH before irradiation. The results also showed that MH mediated the effects on radiation sensitivity, in addition to increasing the oxygen tension. These results show different effects of MH on different cells: (i) AIMH exerts a protective effect on the normal hematopoietic stem cells, some leukemia cell lines A20, HL60, K562, and some neoplasma 3LL, LOVO. And MH exhibits a synthetic effect with anesthetic. (ii) MH enhances the radiation sensitivity of another leukemia and neoplasma cell lines FBL3, B16F10 and CT26. Therefore, AIMH has a potential to enhance the effects of radiation-therapy and decrease side effects on some tumors.