Zettergren L D, Boldt B W, Petering D H, Goodrich M S, Weber D N, Zettergren J G
Department of Biology, Carroll College, Waukesha, WI 53186.
Toxicol Lett. 1991 Jan;55(1):11-9. doi: 10.1016/0378-4274(91)90022-x.
Uninjected (Group I) and sheep erythrocyte (SRBC)-injected (Group II) Rana tadpoles were exposed to varying sublethal concentrations of cadmium (Cd) for 6 weeks. In order to assess possible effects on the tadpole immune system we determined pre-B, B mu, and plasma cell (PC mu) frequencies in liver and mesonephros of Group I larvae, and hemagglutinating antibody (HA) titers of Group II animals. Group I and Group II control animals were cultivated in water with no added Cd (0 ppm), while treatments were set at 0.1, 0.2, 0.4 and 0.8 ppm Cd. We found that (a) Cd appeared to stimulate a significant increase in the frequency of B mu cells in animals treated at 0.4 and 0.8 ppm, (b) certain treated Group II larvae contained significantly increased amounts of HA in their serum, while their serum protein concentrations were not significantly different, and (c) there was a dose-related increase in tissue Cd levels in treated Group II larvae. Our observations suggest that chronic low-level exposure to Cd may (a) result in a slight increases in the frequency of B mu cells in unimmunized animals, (b) increase immune responsiveness of immunized larvae, and (c) increase liver and mesonephros accumulations of Cd. Preliminary studies indicated that cytosolic Cd is associated with a protein which appears to be similar to mammalian metallothionein.
未注射（第一组）和注射了绵羊红细胞（SRBC）（第二组）的林蛙蝌蚪暴露于不同亚致死浓度的镉（Cd）中6周。为了评估对蝌蚪免疫系统可能产生的影响，我们测定了第一组幼虫肝脏和中肾中的前B细胞、Bμ细胞和浆细胞（PCμ）频率，以及第二组动物的血凝抗体（HA）滴度。第一组和第二组对照动物在未添加Cd（0 ppm）的水中培养，而处理组设置为0.1、0.2、0.4和0.8 ppm Cd。我们发现：（a）在0.4和0.8 ppm处理的动物中，Cd似乎刺激Bμ细胞频率显著增加；（b）某些经处理的第二组幼虫血清中HA含量显著增加，而其血清蛋白浓度无显著差异；（c）经处理的第二组幼虫组织Cd水平呈剂量相关增加。我们的观察结果表明，长期低水平接触Cd可能：（a）导致未免疫动物中Bμ细胞频率略有增加；（b）提高免疫幼虫的免疫反应性；（c）增加肝脏和中肾中Cd的积累。初步研究表明，胞质Cd与一种似乎类似于哺乳动物金属硫蛋白的蛋白质相关。
