폐흡충(Paragonimus Tuestermani) 피낭유충에 대한 대식세포의 세포독성에 있어서 항체 및 보체가 미치는 영향

The effects of antibodies and complement in macrophage-mediated cytotoxicity on metacercariae of the lung fluke, Paragonimus westeymani

폐흡충(Paragonimus Tuestermani) 피낭유충을 흰쥐(Wistar) 및 고양이에 감염시키고 감염 힐청이나 분회분리된 IgG또는 보체가 정상 또는 감염 흰쥐 복강 대식세포의 폐흡충 유충 살충에 어떠한 영향을 미치는지 부착 실험 (adherence assay) 및 세포독성을 통하여 관찰하였다. 폐흡충 감염은 복강 대식세포를 비특이적으로 활성화시퍼 대식세포의 유충에 대한 부착률 및 세포독성을 증가시켰으며, 감염 혈청을 첨가하였을 때 항체-의존 세포매개성 세포독성에 의해 배양 6시간 후에 세포 부착률 및 세포독성이 가장 강하였다. 감염 혈청을 56℃에서 30분간 가열하였을 때 IgG 항체 변성에 의해 세포독성이 저하되었다. IgG 및 보체를 첨가한 경우 세포 부착률은 낮았으나 24시간 후에는 유충이 사멸하였다. 그러나 보체의 단독적인 역할은 이 실험에서 알 수 없었다.

Paragonimus westermani is a tissue migrating parasite in the early stage until arriving at lung, and most of the parasites spend their life spans there. Considerable immune responses including activation of macrophages are taken place during the residence of parasites in the host. However, concerning the immunologic defense mechanisms of the host against this parasite, only a few document is available so far. In this study, the cytotoxic effect of peritoneal macrophages under the presence of antibody and/or complement against metacercariae of F. westermani was investigated in vitro. Metacercarlae were collected from the crayfish, Cambaroides similis and hatched out in Tyrode solution (pH 7.4). Plastic adherent cells from normal or infected rat (Wistar) peritoneal exudates were used as experimental macrophages. Polyclonal antibodies were obtained from infected rats and a cat. Cat IgG was fractioned with ion exchange chromatography. Fresh rabbit complement was used according to experimental scheme. Various combinations of peritoneal macrophages, normal or infected rat serum, complement and cat IgG were incubated at $36^{\circ}C$ in 5% $CO_2$ incubator for 6, 14, 24 and 48 hours. The results obtained were as follows: 1. P. westermani infection activated peritoneal macrophages non-specifically and this activation induced increases of cell adherence and cytotoxicity on metacercariae. 2. In the presence of infected rat serum the antibody.dependent cell-mediated cytotoxicity of peritoneal macrophages on metacercariae was significantly increased and showed a peak at 6-hour incubation. But the cytotoxic effect was markedly reduced after inactivation of complement and heat.labile IgE antibody by the heating of infected serum at 56$^{\circ}C$ for 30 minutes. 3. The highest cytotoxic effect (100%) of concomitant incubation with IgG and complement showed 24 hours after incubation, although cell adherence was relatively low at 6-hour incubation and 0% at 24-hour incubation. 4. Coordinative functions of complement with serum and IgG were effective in cell adherence and in cytotoxicity, but it is not clear the independent role of complement on the macrophage- mediated cytotoxicity in this study- With these results it is assumed that P. westermani infection can induce the non-specific activation of peritoneal macrophages, and strum antibodies including IgE antibody might enhance the cytotoxicity by macrophages,