【摘要】 本研究首次检测到斑马鱼(Danio rerio)受精卵中存在母源性补体成分C3和Bf。在斑马鱼卵子胞浆中加入适量C3(所有补体激活途径的关键因子)抗体使补体C3沉淀失活,或将卵子胞浆45℃水浴30min(热灭活补体),均可显著降低卵子胞浆的抑菌率,说明斑马鱼卵子胞浆中的补体系统具有免疫活性。在此基础上,通过补体激活途径的抑制实验研究了母源性补体的作用方式。向斑马鱼卵子胞浆中分别加入适量C1q(经典途径关键成分)抗体和C4(同时参与经典途径和凝集素途径)抗体对其抑菌率无显著影响,而加入Bf(替代途径关键成分)抗体却能够显著降低卵子胞浆的抑菌率。另外,在斑马鱼卵子胞浆中加入EGTA螯合Ca2+抑制经典途径和凝集素途径,卵子胞浆的抑菌率并无明显变化,而加入EDTA同时螯合Ca2+和Mg2+使替代途径也受到抑制后,溶菌率则显著降低。补体途径抑制实验证明,斑马鱼早期胚胎中的补体成分主要是通过替代途径发挥作用。更多还原

【Abstract】 The presence of maternal complement C3 and Bf in fertilized eggs of zebrafish D.rerio was verified.Moreover,it was shown that E.coli was sensitive to the zebrafish egg cytosol,and maternal complement was involved in the bacteriolytic activity.First,the immune activity was abolished by pre-incubation of anti-C3 antibody with the egg cytosol,a process which would cause the precipitation of the central component of all known complement pathways,C3.Second,the lytic activity was depleted by heating at 45℃(a temperature known to inactivate fish complement).To determine which pathway of complement activation might be involved in the bacteriolytic activity of the egg cytosol,the antibodies against C1q(a key component of classical pathway),C4(a key component of both classical and lectin pathways)and Bf(a key component of alternative pathway)were utilized to block the special complement pathway,respectively.It was found that precipitation of C1q and C4 causes little loss of the bacteriolytic activity of the egg cytosol,whereas precipitation of Bf results in a significant reduction of the bacteriolytic activity.Furthermore,addition of EGTA to remove Ca2+(necessary for both classical and lectin pathway)from the egg cytosol induces little decrease in the bacteriolytic activity.In contrast,pre-incubation of EDTA to remove both Ca2 + and Mg2(+necessary for alternative pathway)from the egg cytosol leads to a substantial reduction of the bacteriolytic activity.Taken all the above results into consideration,it was found that activation of alternative pathway is responsible for the bacteriolytic activity of the maternal complement in zebrafish egg cytosol.更多还原