Immunoblot analysis of antigens from Parastrongylus cantonensis, P. costaricensis and P. malaysiensis using serum antibodies against P. cantonensis.

Parastrongylus cantonensis, P. costaricensis and P. malaysiensis adult worm antigens were tested for cross-reactivities in immunoblots using sera from patients with parasitologically confirmed parastrongyliasis. Sera from P. cantonensis-infected patients with a high specificity for the 31-kDa diagnostic P. cantonensis antigen cross-reacted with a corresponding component found in P. costaricensis and P. malaysiensis. The immune sera consistently recognized a prominent immunogenic band with a MW of 31 kDa against the antigens prepared from the 3 Parastrongylus species. Sera obtained from patients infected with Gnathostoma spinigerum and normal healthy control sera did not react with the 31-kDa protein from the 3 species of Parastrongylus. The cross-reactivity observed in the immunoblots performed on serum samples from patients with P. cantonensis infection indicates that the 3 Parastrongylus species share the specific 31-kDa antigen. This protein may be used for the immunodiagnosis of human infection with P. costaricensis and P. malaysiensis.