비장적출된 BALB/c 마우스에 동종항원으로 면역접종하였을 때 병원성 자유생활 아메바, 즉 점천간출a fowzeri o 359의 감염에 의한 사망률, 생존기간을 항체생성과 관련하여 관찰함으로써 비 장적출이 숙주의 체액성 면역기전에 어떤 영향을 미치는지 관찰하였다. 실험 I군은 비장을 적출하고 면역후 감염, II군은 비장적출후 감염, 여군은 면역후 감염, 사군은 대조군으로서 감염만시킨 군 등으로 구분하여 5~10${ imes}$105 아메바를 1주 간격으로 2회 복강내에 주입하여 면역접종하였으며 2회 접종 1주 후에 5~10${ imes}$104 아메바를 비강내에 감염시켜 감염 31일까지 관찰하였다. 감염후 사망률은 면역된 I 및 III군에서 각각 38.1% 및 25%로 II군 50%나 IV군 46.4%에 비해 낮았다. 사망한 마우스의 평균 생존기간은 I군 $20.1{pm}3.6$일, II군 $17.3{pm}4.5$일, III군 $20.4{pm}7.0$일 및 비군 $19.6{pm}7.6$일로 각 실험군간에 차이가 없었다. 감염 31일 후 혈중 IgG 항체가(ELISA치)는 면역군인 I군 및 III군에서 각각 $1.10{pm}0.29$ 및 $1.31{pm}0.28$로 대조군의 $0.24{pm}0.37$보다 훨씬 높았다 (p<0.05). 이러한 성적으로 보아 비장적출 마우스에서 면역후 N. fowleri를 감염시켰을 때 마우스 생존기간의 차이는 없으나 사망률은 면역시킨 군에서 낮아 비장적출후에도 체액성 면역 이 방어기전으로 존재하는 것으로 생각되었다.
A pathogenic free-living amoeba, Naegleria fowleri, is a causative protozoan parasite of primary amebic meningoencephalitis in human and experimental animals. It is known that humoral and cellular immunity contribute as the defence mechanism of host against this organism. Recently splenectomy has been argued on its effect on host defence mechanisms. The present study was aimed to observe the enact of immunization in splenectomized mice. For immunization, $5~10{ imes}10^5$ trophozoites of Naegleria fewleri o 359 were intraperitoneally inoculated once a week for two weeks to BALB/c mice, and $5~10{ imes}10^4$ of ameba trophozoites were intranasally inoculated for infection after splenectomy and/or immunization. ELISA technique was applied for the detection of seum IgG antibody levels. Experimental animals were divided into 4 groups; I. splenectomized and immuniEed; ll. splenectomized only; III. immunized only; IV. not splenectomized nor immunized. The results obtained were as follows: 1. Mortality rates of splenectomized and immunized mice in group I (38.1%) and immunized only in group III (25.0%) were lower than those of not immunized mice in group II (50%) and control group, IV (46.4%). 2. Survival times of mice in group I, II, III and IV were $20.1{pm}3.6$, $17.3{pm}4.5$, $20.4{pm}7.0$ and $19.6{pm}7.6$ days respectively, and there were no significant differences between them. 3. ELISA values (absorbance at 492nm) of group I (1, $10{pm}0.29$) and group III ($1.31{pm}0.28$) were significantly higher than that of group IV($0.24{pm}0.37$) at day 31 of infection (p<0.05). Conclusively, it is presumed that humoral immunity against N. fowleri may operate as ever, after immunization, even though the mouse was splenectomized.
