Tityus SCORPIONS AND CROSSREACTIVITY BETWEEN THESE VENOMS.
P. Parrilla-Alvarez
, G. D´Suze
, M. Quiroga
, A. Rodríguez-Acosta
, C. Sevcik
Laboratorio de Alacranología, Escuela de Medicina, Universidad de Oriente, Núcleo de Bolívar, Ciudad Bolívar, Venezuela. Laboratorio de Neurofarmacología Celular, Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas (IVIC), Apartado 21827, Caracas. D.F. Venezuela. Sección de Inmunoquímica, Instituto de Medicina Tropical, Facultad de Medicina, Universidad Central de Venezuela. Caracas, Venezuela
Venoms of Venezuelan scorpions of the Tityus genus were obtained by electrical stimulation of the telson. The (SQ) LD50 in 1 h was determined in mice C57/B (14 to 18 g) using the sequential method of Dixon and Mood (1948). The LD50s were as follows: Tityus discrepans 8.8 (8.3, 9.4) mg/kg mouse; Tityus ivic-nancor n.sp (González-Sponga) 8.9 (8.4, 9.4) mg/kg mouse, and Tityus caripitensis n.sp. (Quiroga) 14.6 (13.7, 15.4) mg/kg mouse. The effects described for the venoms of the other scorpions were shown by all the animals. Ten milligrams of each venom was detoxified using increasing doses of formalin (Sadahiro, 1971). Eight mg/kg of this substance was (SQ) injected 3 times into mice at 21-day intervals. The first two doses were emulsified using incomplete Freunds Adjuvant. The antigenicity of the formaldehyde-treated venom (Toxoid) was compared with that of the fresh venom and with venom processed as above, but without formaldehyde (aged venom). A group of mice (controls) were injected only with distilled water. The animals were bled from the tail 100 days after the third dose. The serum, obtained by post-clotting centrifugation, was divided in aliquots and maintained at 20°C. The sera diluted 1:200 were then evaluated by inmunoenzymatic assays (ELISA). Immediately after tail bleeding, the mice were injected with 1 LD50 of venom. The treatment with Toxoid did not produce adverse effects and was efficient in inducing immunity, while the treatment with aged or fresh venom produced variable toxic effects (11% of deaths with fresh venom), especially with the first dose. The results of the ELISA demonstrated that the Toxoid was more immunogenic [1.86 (1.79, 1.92) A at 490 nm] than the fresh venom [1.35 (1.28, 1.41) A] or the aged venom [0.83 (0.74, 0.93) A]. The three treatments, however, were equally efficient in inducing protection against 1 LD50 of venom. The comparison of heterologous reactivity between the sera, obtained from mice treated with Toxoid and the studied venoms, showed a high crossreactivity (between 70 to 100%). Formaldehyde eliminated the toxicity of the venoms, increasing the antigenicity, but did not modify their ability to induce protective response in mice.
(Partially financed by CONICIT, Project S1-95000722).
Publication Dates
-
Publication in this collection
16 Apr 1999 -
Date of issue
1999
