Periodate-sensitive immunological cross-reactivity between keyhole limpet haemocyanin (KLH) and serodiagnostic Schistosoma mansoni egg antigens

Both CEF6, a cation-exchange fraction of soluble Schistosoma mansoni egg an tigens (SEX), composed of the 2 antigens, alpha-1 and omega-1, and haemocya nin from the keyhole limper, Megathura crenulata, have shown potential for immunodiagnosis of human schistosomiasis. Possible cross-reactivity between antigens in SEA and keyhole limpet haemocyanin (KLH) was explored by Weste rn immunoblotting and enzyme-linked immunosorbent assay (ELISA) using sera from rabbits immunized with KLH, SEA, CEF6, alpha-1, omega-1, or egg antige n k5. Both immunoassays revealed a high degree of serological cross-reactiv ity between the schistosome egg antigens and KLH, much of it due to sodium periodate-sensitive epitopes. Cross-reactivity with schistosome antigens wi th proven diagnostic efficacy may thus, in part, explain the usefulness of KLH for the diagnosis of human schistosomiasis mansoni.