ELISA for diagnosis of gnathostomiasis using antigens from Gnathostoma doloresi and G. spinigerum.

ELISA was developed for the detection of IgG antibody in sera obtained from patients in Japan and in a foreign country. Gnathostoma doloresi adult antigen was less specific than G. spinigerum advanced third-stage larval antigen but their sensitivity were similar. Cross reactivity was observed in Toxocara canis-, Anisakis-, Paragonimus westermani- and Fasciola-infected sera when G. doloresi adult worms but not G. spinigerum advanced third-stage larvae were used as antigens.

Demonstration of species-specific antigens of Gnathostoma spinigerum, a preliminary attempt.

An attempt was made to demonstrate the presence of species-specific antigens for Gnathostoma spinigerum advanced third-stage larvae (GsAL3) in a rabbit receiving weekly immunization with GsAL3 for seven weeks. The homologous and heterologous antibodies against GsAL3 and G. doloresi adult worm (Gd) antigens were initially detected by immunoelectrophoresis (IEP) and ELISA after the second immunization, and their levels were gradually increased with the number of immunizations. Though cross-reactivity between GsAL3 and Gd were shown with both tests, species-specific antibodies for the homologous antigens were demonstrated. After cross-absorption of rabbit hyperimmune serum was collected after the seventh immunization, seven 'putative' species-specific precipitin bands of GsAL3 were identified. The ELISA values of the rabbit hyperimmune serum showed 50% inhibition after absorption with 0.7 micrograms/ml of homologous GsAL3 antigens as opposed to 1.0 micrograms/ml of the heterologous Gd antigens.

Anatomical localization of Gnathostoma spinigerum larval antigens by an indirect fulorescent antibody test.

Indirect fluorescent antibody test (IFAT) was performed on sections of Gnathostoma spinigerum advanced third-stage larva with gnathostomiasis, angiostrongyliasis, trichinosis, strongyloidiasis and cysticercosis sera. Positive fluorescence was observed with the first three sera. Fluorescence was associated with the anterior part of the esophagus, surface of the cuticle and cytoplasmic granules of the intestine. Absorption of sera with gnathostome antigen did not elicit fluorescence. The results suggest that substances secreted from the esophagus and intestine constitute antigens in excretory-secretory products of the larva.

A study on immunodiagnosis of gnathostomiasis by ELISA and double diffusion with special reference to the antigenicity of Gnathostoma doloresi.

In order to diagnose gnathostomiasis immunologically, Gnathostoma doloresi was evaluated for the antigenicity in comparison with G. hispidum which was recently reported in Japan by using micro-ELISA. The study revealed that G. doloresi can be used as the alternate source of antigen in the test. A significant increase of specific IgG antibodies was seen in 22 (73.3%) out of 30 gnathostomiasis cases. Although double diffusion was slightly less sensitive than ELISA, it was considered more specific than the latter method.

Detection of humoral immune response to Gnathostoma spinigerum in mice.

The humoral immune response to early third stage larvae (EL3) and advanced third stage larvae (AL3) of Gnathostoma spinigerum infection was studied in mice by Ouchterlony gel diffusion technique. The antibodies was detected at week 3 in mice infected with EL3 and remained up to week 10 after infection. Highest positive sample of sera were demonstrated at week 4 to week 7. Similar results were obtained from AL3 infected sera except the antibodies was found and disappeared earlier (week 2 to week 6). G. spinigerum larvae recovery from mice in both groups showed that the number of advanced third stage larvae located in muscle correlated to the peak of positive sera. No cross reaction was observed on positive sera of G. spinigerum and antigens of A. cantonensis, P. siamensis, T. spiralis, O. viverrini and A. ceylanicum. Cross reaction was shown on the G. spinigerum antigen against rat sera with angiostrongyliasis and bandicoot sera with paragonimiasis.