A SCHISTOSOMA-MANSONI FATTY-ACID-BINDING PROTEIN, SM14, IS THE POTENTIAL BASIS OF A DUAL-PURPOSE ANTI-HELMINTH VACCINE

Molecular cloning of components of protective antigenic preparations h as suggested that related parasite fatty acid-binding proteins could f orm the basis of the protective immune crossreactivity between the par asitic trematode worms Fasciola hepatica and Schistosoma mansoni. Mole cular models of the two parasite proteins showed that both molecules a dopt the same basic three-dimensional structure, consisting of a barre l-shaped molecule formed by 10 antiparallel P-pleated strands joined b y short loops, and revealed the likely presence of crossreactive, disc ontinuous epitopes principally derived from amino acids in the C-termi nal portions of the molecules. A recombinant form of the S. mansoni an tigen, rSm14, protected outbred Swiss mice by up to 67% against challe nge with S. mansoni cercariae in the absence of adjuvant and without p rovoking any observable autoimmune response. The same antigen also pro vided complete protection against challenge with F. hepatica metacerca riae in the same animal model. The results suggest that it may be poss ible to produce a single vaccine that would be effective against at le ast two parasites, F. hepatica and S. mansoni, of veterinary and human importance, respectively.