ANTIGENIC CROSS-REACTIVITY OF VENOMS FROM MEDICALLY IMPORTANT LOXOSCELES (ARANEAE) SPECIES IN BRAZIL

Antigenic cross-reactivity between the components of venoms from three spiders of the genus Loxosceles, L. gaucho, L. laeta and L. intermedi a, was studied. Species-specific antisera were prepared by immunizatio n of rabbits with each venom. Anti-L. gaucho horse hyperimmune serum p rovided by the Butantan Institute for treatment of accidents with thes e spiders was also used. Separation by SDS-PAGE showed the existence o f many common components in the three antigens. No individual antigen was observed. Analysis of the antisera by ELISA and Western blotting s howed cross-reactivity as well as several common bands between the thr ee venoms. The horse anti-L. gaucho venom serum recognized many common proteins when antigens of the other two species were used. Antigens i n the range of 33,000-35,000 mol, wt showed most crossreactivity. Both horse and rabbit anti-venom sera contained antibodies able to neutral ize the lethal and dermonecrotic activities of the venom of the three species studied.