Abstract
This study was undertaken to investigate the eftects of Cd administered ad libitum for 6 weeks on the cellular immune responses of Balb/c mice. The results were summarized as follows; 1. The mice fed 25, 50 and 100ppm Cd drank as much as control, but the mice fed 200ppm Cd drank significantly less water after Cd exposure than did control. Increasing rates of body weight of Cd-fed mice for 6 weeks were as this, control group 27.0%, Cd administered groups(25, 50, 100 and 200ppm) 28.54%, 28.31%, 20.49% and 18.04%, respectively. 2. Absolute spleen to body weight(mg/g) of control, 25, 50, 100 and 200ppm Cd administered groups were $4.34{\pm}0.23$, $4.20{\pm}0.54$, $4.80{\pm}0.87$, $4.25{\pm}0.32$ and $4.40{\pm}0.32$, respectively. Splenic cellularity(${\times}10^7$) of control was $24.29{\pm}5.98$ but increased to $27.72{\pm}5.48$, $32.96{\pm}8.44$, $28.32{\pm}8.76$ and $29.64{\pm}4.08$ in 25, 50, 100 and 200ppm Cd-fed groups, respectively. 3. Total $CD_4{^+}$ cells(${\times}10^7$) of control, 25, 50, 100 and 200ppm Cd-fed groups were $9.15{\pm}2.24$, $10.40{\pm}2.04$, $12.04{\pm}3.08$, $10.20{\pm}3.16$ and $10.80{\pm}1.48$, respectively and total $CD_8{^+}$ cells(${\times}10^7$) of these groups were $2.32{\pm}0.56$, $2.54{\pm}0.27$, $3.12{\pm}0.80$, $2.25{\pm}0.70$ and $2.24{\pm}0.28$, in order. On the other hand, $CD_4{^+}/CD_8{^+}$ ratios in total cells were increased significantly except for 50ppm Cd-fed group($3.88{\pm}0.01$). And that of control was $3.97{\pm}0.02$, but those of 25, 100 and 200ppm were $4.35{\pm}0.01$, $4.54{\pm}0.03$ and $4.81{\pm}0.03$. 4. Phagocytosis rates of peritoneal macrophages were increased significantly in 25 and 50ppm Cd groups($36.34{\pm}9.45$ and $37.15{\pm}9.22$, respectively), but 100 and 200ppm groups showed similar rates($18.20{\pm}3.04$ and $19.48{\pm}3.22$ respectively) to that of control($21.43{\pm}3.62$). 5. In mitogen-induced splenocyte proliferation, various concentraions of $CdCl_2(10^{-4}-10^{-7}M)$ were added to mitogen-stimulated culture in vitro. Splenocyte proliferation induced by LPS was decreased dose dependently, but proliferation by Con-A was increased slightly in concentrations of $10^{-7}-10^{-6}M$. 6. Significant cytotoxicity of splenocytes with $CdCl_2$ were shown at $10^{-4}M$ treated group, especially at 24 hrs. From these results, it could be concluded that Cd might modulate the immune responses by modifying a distribution of T cell subpopulations.
카드뮴이 BALC/c 마우스의 세포성면역능에 미치는 영향을 평가하고자 여러 농도의 카드뮴이 첨가된 음료를 장기간 동안 자유급식하고, 비장내 T helper 및 T suppressor cell의 분포도, 복강대식세포의 탐식능 및 시험관내에서 Con-A 및 LPS에 대한 비장세포의 증식능을 조사하여 다음과 같은 결과를 얻었다. 1. 각군의 6주간 체중 증가율은 대조군이 27.0%이었으며, 25, 50, 100 및 200ppm $CdCl_2$, 투여군의 체중증가율은 각각 28.54%, 28.31%, 20.49% 및 18.04%로 나타났다. 2. 체중당 비장무게(mg/g)는 대조군이 $4.34{\pm}0.23$이었으며, 25, 50, 100 및 200ppm $CdCl_2$, 투여군은 각각 $4.20{\pm}0.54$, $4.80{\pm}0.87$, $4.25{\pm}0.32$ 및 $4.40{\pm}0.32$이었다. 또한 총비장세포수(${\times}10^7$)는 대조군($24.29{\pm}5.98$)에 비해 25, 50, 100 및 200ppm $CdCl_2$, 투여군에서 각각 14.1%, 35.7%, 16.6% 및 22.0%증가하였다. 3. 총 $CD_4{^+}$ 세포수(${\times}10^7$)는 대조군이 $9.15{\pm}2.24$, 25, 50, 100 및 200ppm $CdCl_2$, 투여군은 각각 $10.40{\pm}2.04$, $12.04{\pm}3.08$, $10.20{\pm}3.16$ 및 $10.80{\pm}1.48$ 이었으며, 총 $CD_8{^+}$ 세포수(${\times}10^7$)는 대조군이 $2.32{\pm}0.56$, 각 실험군의 총세포수는 $2.54{\pm}0.27$, $3.12{\pm}0.80$, $2.25{\pm}0.70$ 및 $2.24{\pm}0.28$ 이었다. 한편, $CD_4{^+}/CD_8{^+}$ 비율은 50ppm 투여군($3.88{\pm}0.01$)을 제외하고 모든 실험군에서 대조군($3.97{\pm}0.02$)에 비해 유의하게 증가하였다(p<0.001). 4. 카드뮴 처리군의 SRBC에 대한 복강대식세포의 탐식능은 25 및 50ppm 투여군에서는 대조군에 비하여 유의하게 높았으나(p<0.05 및 p<0.01), 100 및 200ppm 투여군에서는 대조군과 유사하였다. 5. 시험관에서의 Con-A 및 LPS에 대한 비장림프구 증식반응은 LPS의 경우 카드뮴 농도에 비례하여 억제되었으나 Con-A에 대한 증식반응은 저농도($10^{-7}-10^{-6}M$)에서 증가된 양상을 보였다. 6. $CdCl_2$에 대한 비장세포의 세독독성은 $10^{-4}M$에서 특히 높았다. 이상의 결과는 카드뮴이 세포성면역반응에서 중요한 역할을 하는 T세포 아군의 분포도를 변화시키므로써 면역반응에 영향을 줄 수 있음을 시사한다.
(College of Veterinary Medicine, Chonbuk National University)