In order to obtain more specific antigenic preparation for the diagnosis of human paragonimasis, crude saline extract of whole worm (=PwWWE), secretory-excretory components (PwSEC) and secretion-excretion-free somatic extract (PwSM) of 12 week-old Paragonimus westermani were filtrated through Sephadex G-200 gel column. The adult Paragonimus worms were obtained from experimentally infected dogs. A total of 11 antigenic solutions was lyophilized or diluted to adjust protein content of 1 mg/ml. To evaluate the antigenicity of crude antigens and fractions, micro-ELISA was done with the sera from P. westermani infected cases, C. sinensis infected cases and non-infected control cases to detect Paragonimus specific IgG antibody. The results were as follows: When the PwWWE was filtrated through Sephadex G-200 gel, it was separated into three fractions; PwWWE Fr. 1, PwWWE Fr. 2 and PwWWE Fr. 3. The percentage of protein content was 28.0 percent, 21.6 percent and 50.4 percent respectively. The PwSM was also separated into three fractions; PwSM Fr. 1, PwSM Fr. 2, PwSM Fr. 3 and their percentage of protein content was 41.3 percent, 38.6 percent and 20.1 percent. However, the PwSEC showed different fractionation pattern; i.e. fraction 1 (=PwSEC Fr. 1) and 3 (PwSEC Fr. 3) without fraction 2. The percentage of protein content was 14.0 percent in PwSEC Fr. 1 and 86.0 percent in PwSEC Fr. 3. When the antigenicity of each Paragonimus crude antigen and fractionated antigen was evaluated for specific IgG antibody by micro-ELISA in 10 human paragonimiasis sera, PwSEC Fr. 1 was the most potent antigen showing the mean absorbance 1.98. The PwWWE Fr. 1, PwSEC, PwWWE were next to that; their mean absorbance were 1.72, 1.38 and 0.83, respectively. The antigenicity of fractions 2 and 3 was much weaker in binding specific IgG antibody. When the antigens were reacted in micro-ELISA with 10 human clonorchiasis sera, most antigens showed weak reactivity. Each fraction 1 of crude antigens reacted higher than other fractions or crude antigens; the mean absorbance was 0.17 in fraction 1, but in others the absorbances were about 0.06. With non-infected control sera, the result of micro-ELISA revealed almost same pattern with those of the clonorchiasis sera. From the above results, it became apparent that PwWWE Fr. 1, especially PwSEC Fr. 1 was the most potent antigen reacted with Paragonimus specifc IgG antibody.
