Immunoblot evaluation of the specificity of the 29-kDa antigen from young adult female worms Angiostrongylus cantonensis for immunodiagnosis of human angiostrongyliasis.

The antigenic components of Angiostrongylus cantonensis young adult female worm somatic extract (FSE) were revealed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting. The sera tested were from patients with proven angiostrongyliasis, other parasitic diseases, and healthy adults. Both the sera and cerebrospinal fluid (CSF) were tested from patients with clinical angiostrongyliasis. The CSF from patients with other neurological diseases were also included. Using SDS-PAGE, we found that the FSE comprised more than 30 polypeptides. Immunoblot analysis revealed at least 12 or 13 antigenic bands in patients with proven or clinical angiostrongyliasis, respectively. The patterns of reactivity recognized by the serum and CSF antibodies against FSE were similar. These antigenic components had molecular masses ranging from less than 14.4 to more than 94 kDa. The prominent antigenic band of 29-kDa might serve as a reliable marker for the diagnosis of angiostrongyliasis. The sensitivity, specificity, positive and negative predictive values of immunoblot analysis in this antigenic band were 55.6%, 99.4%, 83.3% and 97.4%, respectively.