These suggested that so2 may affect body immunity to a certain degree . ( 3 ) effects on mouse thymus of so2 challenge : he staining showed no obvious structure changes of thymus in all treatment groups compaired with the control group ; the ultrastructure of thymus can be seen injured in so2 treated groups from tem observation ( 3 )二氧化硫染毒对小鼠胸腺组织学结构影响较小：用透射电镜观察发现胸腺组织中有部分淋巴细胞变形且异染色质增多，胸腺上皮细胞中可见次级溶酶体增多，线粒体变形，这说明二氧化硫可能对中枢免疫器官也有一定的不良影响。
