Ingestion of Cryptosporidium oocysts by Caenorhabditis elegans.

Cryptosporidium parvum has been associated with outbreaks of human illness by consumption of contaminated water, fresh fruits, and vegetables. Free-living nematodes may play a role in pathogen transmission in the environment. Caenorhabditis elegans is a free-living soil nematode that has been extensively studied and serves as a good model to study possible transmission of C. parvum oocysts that may come into contact with produce before harvest. The objective of this study was to determine whether C. elegans could serve as a potential mechanical vector for transport of infectious C. parvum and Cyclospora cayetanensis in agricultural settings and whether C. elegans could ingest, excrete, and protect oocysts from desiccation. Seventy to 85% of worms ingested between 0 and 500 oocysts after 1 and 2 hr incubation with oocysts. Most of the nematodes ingested between 101 and 200 oocysts after 2 hr. Intact oocysts and empty shells were excreted by nematodes. Infectivity was determined by the neonatal assay with different treatments of worms (intact or homogenized) or oocysts or both. Adult C. elegans containing C. parvum kept in water were infective for mice. In conclusion, C. elegans adults can ingest and excrete C. parvum oocysts. Caenorhabditis elegans containing C. parvum oocysts can infect mice but does not seem to protect oocysts from extreme desiccation at 23 C incubation of a day or longer. Cyclospora oocysts were not ingested by C. elegans. The role of free-living nematodes in produce contamination needs to be further examined.

Antígenos de larvas pulmonares de Ascaris suum reconocidos por anticuerpos producidos en Oryctolagus cuniculus / Ascaris suum lung larvae antigens recognized by antibodies produced in Oryctolagus cuniculus

El presente trabajo tuvo como objetivo determinar mediante la técnica de Western Blot los antígenos de larvas pulmonares de Ascaris suum que son detectados por anticuerpos producidos en Oryctolagus cuniculus inmunizado experimentalmente. Las larvas pulmonares (L3 y L4) fueron obtenidas en 120 ejemplares de Mus musculus cepa BALB/c ratón infectados experimentalmente por vía oral con huevos infectivos de A. suum. Parte de estas larvas fueron cultivadas en el medio Eagle (MEM) para la obtención de antígenos de excreción/secreción y la otra fue sonificada para la obtención de antígenos somáticos, los cuales sirvieron para inmunizar dos ejemplares de O. cuniculus, utilizando Adyuvante Completo e Incompleto de Freund. A las 5 semanas de inmunización se obtuvo sangre de los conejos por punción cardiaca a fin de recuperar el suero, parte del cual fue purificado parcialmente por precipitación salina y diálisis. Mediante la técnica de electroinmuno-transferencia (Western Blot) y usando sueros de los conejos inmunizados se detectaron en los antígenos de excreción/secreción de 20 horas de cultivo reducidos con dithiothreitol, 12 bandas antigénicas de 100, 72.4, 56.2, 42.7, 39.8, 34.6, 31.6, 30.2, 19.5, 16.9, 15.5 y 14.9 KDa, siendo las más reactivas las de 100, 72.4, 16.9, 15.5 y 14.9 KDa. En los antígenos somáticos bajo condiciones de reducción, se detectaron solamente seis bandas de 42.7, 39.8, 34.6, 30.2, 28 y 25.2 KDa de poca reactividad. Estos resultados permiten afirmar que los antígenos de excreción/secreción de A. suum de 20 horas de incubación en el medio MEM inducen la producción de un mayor número de anticuerpos de tipo IgG en conejos inmunizados experimen-talmente.

Excretory/secretory antigens (E/SAg) and somatic antigens (SAg) of Ascaris suum lung larvae that induce the immunoglobulin G antibodies production in Oryctolagus cuniculus experimentally immunized was determined. For this purposes, specimens of Mus musculus BALB/c were inoculated orally with infective eggs of A. suum obtained from pigs naturally parasitized in order to obtain the lung larvae. Part of these larvae was cultured in Minimum Essential Medium (MEM) to obtain E/SAg and another part was sonicated to obtain the SAg too. Both, E/SAg and SAg mixed with complete and incomplete Freund's adjuvant were used for rabbits immunization. Five weeks after the immunization, the rabbits were bled by cardiac puncture obtaining the immunosera by centrifugation, which was purified partially by saline precipitation and dialysis. By using an Western blot technique with purified immunoserum and E/SAg obtained to 20 hours and reduced with dithiothreitol, fourteen antigens bands of 100, 72.4, 56.2, 42.7, 39.8, 34.6, 31.6, 30.2, 19.5, 16.9, 15.5 y 14.9 KD, were detected. The bands of 100, 72.4, 16.9, 15.5 and 14.9 KDa were been the most reactives. Thereby the SAg, also reduced with dithiothreitol, seven bands of 42.7, 39.8, 34.6, 30.2, 28.0 and 25.2 KDa were detected. They were a bit clear. In conclusion, the E/SAg induce the highest production of immunoglobulin G antibodies in rabbits experimentally immunized.