Serodiagnosis of mansonian schistosomiasis with CEF6, a cationic antigen fraction of Schistosoma mansoni eggs.

Studies of the host-parasite relationship of Schistosoma mansoni in mice revealed that the parasite's eggs were toxic to liver cells of immunosuppressed hosts. Attempts to identify the toxic egg constituent led to the isolation of a fraction CEF6 from crude egg homogenate by cation exchange chromatography. CEF6 contains two cationic antigens, omega 1 and alpha 1, the former being recognized as the putative hepatotoxin. In an initial assessment of its serodiagnostic potential in enzyme immunoassay (ELISA), CEF6 yielded an enhanced degree of sensitivity and specificity when compared with crude egg homogenate, and a subsequent 'blind' inter-laboratory collaborative study confirmed that in certain circumstances the use of a purified fraction such as CEF6 may be advantageous. We here review the experimental work leading up to the isolation of CEF6, and summarize the results so far obtained from its use as a diagnostic aid in human schistosomiasis.