Immunological analysis of Mexican coral snake venoms

¹Carbajal-Saucedo, A.; ²Smith, E.N.; ³Estévez, J.; ³Mancilla, J. and ¹Alagón, A.

1 Instituto de Biotecnología, UNAM, Cuernavaca, México, 2 University of Texas at Arlington, USA, 3 Instituto Bioclon, México.

Envenomations by Coral snakes in Mexico are treated with a F(ab’)2 antivenom, Coralmyn^®, raised in horses hyperimmunized with Micrurus nigrocinctus venom. Clinically, Coralmyn^® has proven very effective against some species but of moderate effectivity against others. Here, we have assessed the immunological cross-reactivity of 12 species or subspecies of Mexican Coral snakes venoms and their neutralization by the current Coralmyn^® as well as by two experimental rabbit antisera raised against M. distans and M. laticollaris venoms, respectively. Immunoblotting showed a high cross-reactivity of all major protein bands with all the antibody preparations tested. The ELISA results also showed a high cross-reactivity among the different venoms and antivenoms. These high in vitro cross-reactivities did not match, in many cases, the neutralization potencies of the lethal activity in mice by the antivenoms. Coralmyn^® was very effective neutralizing the homologous venom as well as the one of M. browni and was less effective against the venoms of M. diastema, M. distans, M. fulvius, M. laticollaris and M. limbatus. The anti-M.distans serum was highly protective against M. distans, M. diastema, M. browni and M. nigrocinctus venoms but was ineffective against the venoms of M. fulvius, M. laticollaris and M. limbatus. Surprinsingly, the anti-M.laticollaris serum, with ELISA titers greater than 100,000 to all the venoms, was unable to neutralize their lethality (including the homologous one).

Correspondence to: bothrops@ibt.unam.mx