Pan-African polyspecific antivenom produced by caprylic acid purification of horse IgG: an alternative to the antivenom crisis in Africa.

A polyspecific Pan-African antivenom has been produced from the plasma of horses immunized with a mixture of the venoms of Echis ocellatus, Bitis arietans and Naja nigricollis, the three most medically important snakes in sub-Saharan Africa. The antivenom is a whole IgG preparation, obtained by caprylic acid precipitation of non-IgG plasma proteins. The antivenom effectively neutralizes the most important toxic activities of the three venoms used in the immunization in standard assays involving preincubation of venom and antivenom before testing. This antivenom compares favourably with other antivenoms designed for use in Africa with respect to neutralization of the toxins present in the venom of E. ocellatus. Caprylic acid fractionation of horse hyperimmune plasma is a simple, convenient and cheap protocol for the manufacture of high quality whole IgG antivenoms. It constitutes a potentially valuable technology for the alleviation of the critical shortage of antivenom in Africa.

Purification and partial characterization of phospholipases A2 from Bothrops asper (barba amarilla) snake venom from Chiriguaná (Cesar, Colombia)

Components with phospholipase A2 activity were isolated by gel filtration and cationic exchange chromatography from the venom of Bothrops asper snakes from Chiriguaná, Colombia (9°22´N; 73°37´W). Five fractions were obtained by the gel filtration, and PLA2 activity was found in fraction 3 (F3). In the cationic exchange chromatography, F3 showed eight components with PLA2 activity. Six of these components appeared as one band in polyacrylamide gel electrophoresis (SDS-PAGE). Fractions II and VII exhibited an optimal activity at pH 9 and 52ºC. The optimum calcium concentration for fraction II was 48 mM and for fraction VII, 384 mM. Both fractions showed thermal stability. Fraction II was stable at pH values between 2.5 and 9, and fraction VII, between 2.5 and 8. The Michaelis Menten constant (K M) was 3.5x10-3 M for fraction II and 1.6x10-3 M for fraction VII. The molecular weight was 16,000 Dalton for fraction II and 17,000 Dalton for fraction VII. Both isoenzymes did not show any toxic activity (DL50) at 5.3 and 4 µg/g. The two fractions showed different kinetic constant (K M), calcium requirement, and substrate specificity for haemolytic activity.

A new Pan African polyspecific antivenom developed in response to the antivenom crisis in Africa.

Currently there is a crisis in the supply of antivenom for treatment of snake bite in sub-Saharan Africa. Commercial pressures have resulted in the reduction or even cessation of production of antivenom by European manufacturers while continued production of antivenom in Africa has been threatened by the privatisation of the only remaining company based in Africa. As a consequence, there has been an increase in snake bite morbidity and mortality in many African countries. Two Latin American antivenom manufacturers have agreed to produce antivenom suitable for Africa, using venoms from the species which are of the greatest medical importance in sub-Saharan Africa. Preclinical in vivo assays of neutralising potency demonstrated that a new Pan African antivenom produced in Colombia compared favourably with the existing commercial monospecific and polyspecific antivenoms. This new antivenom, and a similar product being manufactured in Costa Rica, are now candidates for clinical testing at an appropriate site in Africa.

Estabilidad de la actividad neutralizante del antiveneno ofídico conservado a 4ºC y 16ºC contra el veneno de tayas (complejo Bothrops atrox-asper) de Colombia / Stability of the neutralizing activity of ophidic antivenom kept at 4ºC and 16ºC against the venom of tayas (complex Bothrops atrox-asper) of Colombia

En este trabajo se informa acerca de la determinación de la actividad neutralizante de la letalidad de varios lotes de antiveneno ofídico en forma líquida, producidos en el Instituto Nacional de Salud y almacenados en completa oscuridad a 4ºC y a 16ºC. El veneno usado para retar el antiveneno fue una mezcla de venenos de tayas (complejo Bothrops atrox-asper), procedentes de diferentes regiones de Colombia. Se estableció el porcentaje de la potencia remanente de los lotes para cada año y para cada temperatura de almacenamiento, para así corroborar la fecha de expiración del producto en forma líquida. Los resultados de este estudio muestran que el antiveneno conservado en las condiciones de oscuridad a 4ºC, luego de 3 años de almacenamiento mantiene casi la totalidad de la capacidad neutralizante (95 por ciento), mientras que el antiveneno almacenado bajo condiciones de oscuridad a 16ºC, luego de 2 años mantiene el 87 por ciento de su capacidad neutralizante. Así, recomendamos desechar el producto mantenido bajo estas condiciones a los dos años de fabricación