Determination of localization of allergen and IgG inducing antigen in Dirofilaria immitis by immunofluorescent antibody method.

More detail studies were made into the localization of IgE inducing antigen (allergen) and IgG inducing antigen in the body of adult male and female Dirofilaria immitis worms by the indirect immunofluorescent antibody method using rat sera against purified allergen and IgG inducing antigen. Allergen was detected in large amounts in the body cavity fluid and the excretory canal, and it was also detected in the cuticles and the lateral lines in the vicinity of the excretory canal. IgG inducing antigen was found in the largest amount in the site of musculature inside of cuticle. Besides the musculature, it was also recognized in smaller amounts in the muscle layer, the body cavity fluid and the excretory canal. In females it was also detected on the surface of microfilaria in the uterus. As to allergen as well as IgG inducing antigen, the fluorescence was recognized most strongly in the central part of the worm body, and it tended to diminish gradually as it approached the head and tail. The concentration of allergen determined by the immunofluorescent antibody method was higher in males than in females. Especially in the excretory canal, a difference was seen between males and females. Allergen was thought to be secreted mainly out of the excretory canal and present largely in the body cavity fluid. On the other hand, the site of the musculature inside of cuticle and the muscular layer were supposed to be the major constituents of IgG inducing antigen.