[Immune humoral response in pigs infected with eggs and posoncospheres of Taenia solium]. / Estudio de la respuesta inmune humoral en cerdos infectados con huevos y posoncosferas de Taenia solium.

Due to the importance of cysticercosis in Mexico and Latin America and to the fact that in the last years another mechanism of infection for this disease has been proposed, i.e. through postoncospheres and immunosuppression of the host, we have considered relevant to perform the present work, which consisted in assessing the immune response induced by dexamethasone as well as that produced by parasites in pigs infected with T. solium eggs, or postoncosphere-infected, and in postoncosphere-infected and dexamethasone-treated animals. We used 10 recently weaned pigs, three were used as controls, two of them without the drug and one with it; two were infected with T. solium eggs; five with postoncospheres receiving also dexamethasone three of them. We evaluated the humoral response against parasite antigen using indirect haemagglutination (IH) and ELISA methods. Results of the immune humoral response revealed titres of up to 1:128 in T. solium eggs infected animals, of 1:16 in postoncosphere infected animals, and of 1:32 towards the end of the experiment in postoncosphere plus dexamethasone animals. Absorbance titres with ELISA confirmed these findings. Data obtained by IH show that the antibody titres of the pigs challenged with postoncospheres and postoncospheres plus dexamethasone are positive as compared to the titres obtained in the pigs infected with T. solium eggs. Results from the ELISA confirmed this finding, since, from weeks 14 to 17, the pigs became positive, behaving as those pigs that developed cysticercosis. This is relevant as it indicates that the antiposcosphere antibodies recognized antigens of T. solium larvae.

Immunity against the venom of Mexican scorpion Centruroides lumpidus limpidus induced by some proteins from this venom.

A protein fraction, which consisted of at least 12 proteins, was obtained from the venom of Mexican scorpion Centruroides limpidus limpidus. The molecular weights of these proteins ranged between 9,800 and 163,000 daltons. This fraction was separated from the rest of the venom components, which were almost all neurotoxins, by chromatographying the venom obtained by electrical stimulation through a Sephadex G-50M column. This fraction was non-toxic for mice, even at dose of 200 micrograms/mouse. The most important is that it was able to induce immunity against C. l. limpidus venom, since 92.8% of the animals inoculated with three doses survived after the challenge with 39.2 micrograms of venom (2 DL50 for mice of 20 g); on the contrary, 88 min after the challenge, 100% of the control mice had already died. In another experiment, this immunogen was inoculated into mice three times at variable doses. Seven days after the last injection, each mouse was challenged with 19.6 micrograms of venom. In all controls the typical envenomation picture produced by scorpion venom was developed, and death was registered in 19% of the animals. In contrast, 87% of mice immunized with the highest dose failed to show signs of envenomation or died throughout the observation time. Only two immunized animals (13%) showed mild tachycardia and hyperpnea at 120 min post-challenge. Immunoelectrophoresis and immunodiffusion tests revealed that these proteins induced antibodies against components of the most toxic fraction.