Clone banks of cDNA from the parasite Schistosoma mansoni: isolation of clones containing a potentially immunodiagnostic antigen gene.

We have constructed a small vector specifically for blunt-end cloning of fragments of DNA. Both the PvuII site and the EcoRI site allow the detection of recombinants using a simple and inexpensive colour screen. We have used this vector to construct cDNA clone banks from polyadenylated messenger RNA [poly(A)+mRNA] from several life cycle stages of the human parasite Schistosoma mansoni and have identified clones encoding an immunodiagnostic antigen gene by a combination of Southern blotting and mRNA hybrid-selection and in vitro translation. Antibodies against this antigen are only present in patients infected with S. mansoni.