半相合基因骨髓细胞移植小鼠的嵌合体程度对移植物抗肿瘤效应的影响

Haploidentical bone marrow cell reconstruction of tumor-bearing murine host

目的 探讨半相合基因骨髓细胞移植后受体形成的嵌合体程度对抗肿瘤效果的影响.方法 25只BALB/C青春期小鼠随机分为3组：混合型嵌合体组（A组,10只）、完全型嵌合体组（B组,10只）、对照组（C组,5只）.首先,A、B组小鼠行直线加速器全身照射,剂量分别为4、8Gy,照射后4～6 h内经尾静脉注射入CB6F1代小鼠的骨髓细胞（5×106/只）,C组无处理.A、B、C三组均给予Renca肾癌细胞腋窝下注射,每只2.6×106.观察所有组别小鼠的肿瘤生长速率,通过流式细胞仪测定A、B组小鼠移植后不同时间的嵌合体水平.荷瘤32 d时断颈处死小鼠,取肿瘤组织称重.结果 （1）流式细胞术鉴定血液白细胞中供者源细胞比例：A组移植后2周后形成混合嵌合体（47.51%～72.64%）并达高峰,以后逐渐下降,3～4周时下降至10%以下.B组小鼠移植后14 d形成完全供者型嵌合体（供体细胞＞90%）,28 d后仍达90%以上.（2）与对照组和混合型嵌合体组比较,完全型嵌合体组的肿瘤生长速度明显减慢,肿瘤重量显著减小（P＜0.01）,抑瘤率高达52%.结论 半相合基因骨髓细胞移植后形成的稳定的完全型嵌合体状态是抗肿瘤效应的基础.

Objective To investigate the roles of chimerism level after haploidentical bone marrow cell transplantation on graft versus tumor effect （GVT）. Methods Thirty BALB/C mice were randomly divided into 3 groups： control group （group C, 10）, mixed chimerism group （group A, 10）, full donor chimerism group （group B, 10）. Five BALB/C mice in group C were only inoculated with Renca cells （2.6 × 106）. Ten mice in group A were conditioned with 4 Gy irradiation, followed by infusion by bone marrow cells of CB6F1 mice on the day 1, then inoculated with Renca cells （2. 6 × 106 ） on the day 8. Ten mice in group B were conditioned with 8 Gy irradiation, followed by infusion by bone marrow cells （5 ×106 ） of CB6F1 mice on the day 1, then inoculated with Renca cells （ 2. 6 × 106 ） on the day 8. Tumor growth was monitored every 4 day. In groups A and B, all mice were analyzed by FACScan cytometry on the day 14, 21 and 28 after BMT. Mice were killed at the 32nd day after inoculation with tumor cells and blood of all mice was collected. All tumors were taken out to be weighed. Results The results of chimera showed that engraftments in group A remained mixed donor chimerism and unstable, tended to decrease after 14 days. In group B, full donor chimerism developed, and the chimerism of engraftments remained above 90% and was preserved even after 28 days The size and tumor growth rate in groups B were reduced as compared with groups A and C （P 〈0. 01 ）. The tumor inhibitory rate in groups B was 52%. Conclusion Stable full donor chimerism status after haploidentical allogeneic bone marrow cell transplant is the basis of GVT.