• Parasites, Hosts and Diseases
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• v.34 no.4
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• pp.247-254
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• 1996

Differentiation of invasive strains of Entamoebn histolytica according to their pathogenicity has been a topic of long debate, but now the pathogenic species only is regarded as E. histolytica while the non-pathogenic species is E. dispar. The present study applied immunoblot to differentiale infections of the two species among microscopically- detected cyst-passers in Korea. The crude extract of 5. histolyticn separated in 5-20% gradient gels, revealed many fractions of 94. 81. 71, 50. 44, 38.5. 37.5, 29, 19. and 18 kDa when the cysteine proteinase inhibitor. E64, was supplemented. The serum IgG antibody of 3 proven E. histolytirc cases reacted loth the antigenic fractions of 117. 110. 99.68,66,60.54.52, 46. and 45 kDa. Sera of PCR confirmed 3 cases of E. disper reacted only to the 117 kDa fraction or the E. histolytica crude extract which was regarded as non specific. To the antitigen of monoxenic E. dispar. sera or E. dispar and E. histolytica cases showed the same immunoblot reactions. The serum IgG antibody reacted with several antigenic fractions of both E. histolytica and E. dispar. but IgM and IgE antibodies showed no reaction to either antigen. Sera of 24 symptomless amebic cyst-passers were screened with the E. histolytica alltigen; two were found to be infected by E. histolytica and 22 were by E. dispar. The present findings suggest that in Korea most of asymptomatic cyst passers of E. histolytica are carriers of E. dispar. Immunoblot using E. histolytica antigen is a good technique for the differentiation of E. histolytica and E. dispar infections.

• Parasites, Hosts and Diseases
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• v.26 no.1
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• pp.39-44
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• 1988

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, $5~10{\times}10^5$ trophozoites of Naegleria fewleri o 359 were intraperitoneally inoculated once a week for two weeks to BALB/c mice, and $5~10{\times}10^4$ 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.