注射用重组人B淋巴细胞刺激因子受体-抗体融合蛋白在恒河猴体内的安全性

Safety of recombinant human B lymphocyte stimulating factor antagonist-antibody fusion protein in rhesus monkeys

目的评价注射用重组人B淋巴细胞刺激因子受体-抗体融合蛋白(RCT-18)在恒河猴体内的安全性。方法将恒河猴随机分为4组:低、中、高剂量RCT-18组和对照组,每组8只,低、中、高剂量RCT-18组分别经皮下注射4.6、16.1、57.5 mg/(kg.次)RCT-18,对照组经皮下注射0.7 ml/(kg.次)0.9%氯化钠注射液,每3 d上午同一时间给药1次,共给药91次。每天上午观察记录恒河猴的一般体征,每周常规监测体温1次,并在第1、2、3、13、14、15、28、29和30次给药前、给药后0.5、1、2、4和24 h增加测量动物体温次数。给药0.5、1.5、3、4.5、6、7.5、9个月(停药次日)及停药48 d(恢复期结束),分别对心电图、眼科、血液学、血液生化学、尿常规、血清抗RCT-18抗体、外周血单个核细胞(PBMC)分类计数、血清免疫球蛋白水平(IgG、IgA和IgM)等各项指标进行检查。给药3、6、9个月和恢复期结束,每组各解剖2只猴,进行脏器大体观察,计算脏器系数,并进行组织病理学观察。结果临床反应主要表现为给药后的体温升高;血液学指标出现具有一定剂量-反应关系的单核细胞(monocyte,MONO)数和网织红细胞(reticulocyte,RETIC)升高或网织红细胞平均体积(mean reticulocyte volume,MCVr)降低;3个剂量RCT-18组恒河猴的脏器重量和脏器系数与同期对照组相比,均无明显变化,且未见明显的脏器大体病变;3个剂量RCT-18组均出现无明显剂量相关但可逆的脾小结和淋巴滤泡萎缩;在整个试验期内未检测出血清中的抗RCT-18抗体;3个剂量组外周血淋巴细胞中IgD+细胞(成熟B淋巴细胞)比率均略有下降,但与对照组相比,差异无统计学意义(P>0.05);血清IgG、IgA和IgM从给药0.5～1.5个月后开始明显下降,恢复期结束时,除了中剂量的IgA水平,其他3个剂量RCT-18组的IgG、IgA和IgM水平均出现不同程度的回升。结论 RCT-18对恒河猴具有明显的但可恢复的免疫抑制作用。

Objective To evaluate the safety of recombinant human B lymphocyte stimulating factor antagonist-antibody fusion protein RCT-18 in rhesus monkeys.Methods Rhesus monkeys were randomly divided into four groups,8 for each.The monkeys in low,moderate and high dose RCT-18 groups were injected s.c.with RCT-18 at dosages of 4.6,16.1 and 57.5 mg / kg,while those in control group with 0.7 ml of 9% sodium chloride solution,once 3 days for 91 times.The monkeys were observed for clinical signs once a day,and measured for body temperature once a week.In addition,the body temperatures were measured before and 0.5,1,2,4 and 24 h after the 1st,2nd,3rd,13th,14th,15th,28th,29th and 30th injection.The electrocardiogram（ECG）,ophthalmologic,hematological and hemobiochemical indexes,result of routine urine examination,serum antibody against RCT-18,peripheral blood monocyte（PBMC）count as well as serum IgG,IgA and IgM levels of monkeys were observed 0.5,1.5,3,4.5,6,7.5 and 9 months after the first injection and at the end of recovery period（48 d after the last injection）.Two monkeys in each group were dissected 3,6 and 9 months after the first injection and at the end of recovery period and observed for organs,based on which the organ coefficient was calculated,and the organs were observed for histopathology.Results The adverse reaction was mainly expressed as increased body temperature.Dose-dependent increase of monocytes（MONOs） and reticulocytes（RETIC）and decrease of mean reticulocyte volume（MCVr）were observed.The organ weights and coefficients of monkeys in high,moderate and low dose RCT-18 groups showed no significant changes as compared with those in control group,and no obvious pathological change of organs were observed.No dose-dependent but reversible atrophy in splenic nodules and lymphoid follicles were observed in the three RCT-18 groups.No antibody against RCT-18 was detected during the whole study.The ratio of IgD ＋ cells（mature B lymphocytes） in peripheral blood lymphocytes of three RCT-18 groups decreased slightly while showed no significant difference with that in control group（P 0.05）.Serum IgG,IgA and IgM levels decreased significantly 0.5 ~ 1.5 months after the first injection,while recovered at various degrees at the end of recovery period,except the IgA level in moderate dose RCT-18 group.Conclusion RCT-18 showed significant but recoverable immunosuppression in rhesus monkeys.