Abel Villa-Mancera

Induction of immunity in sheep to Fasciola hepatica with mimotopes of cathepsin L selected from a phage display library

An M13 phage random 12-mers peptide library was used to screen cathepsin L mimotopes of Fasciola hepatica and to evaluate their immunogenicity in sheep. Seven clones showed positive reactivity to a rabbit anti-cathepsin L1/L2 antiserum in ELISA, and their amino acid sequences deduced by DNA sequencing were tentatively mapped on the protein. Twenty sheep were randomly allocated into 4 groups of 5 animals each, for immunization with 1x10(14) phage particles of clones 1, 20, a mixture of 7 clones and PBS, without adjuvant at the beginning, and 4 weeks later. All groups were challenged with 300 metacercariae at week 6 and slaughtered 16 weeks later. The mean worm burdens after challenge were reduced by 47.61% and 33.91% in sheep vaccinated with clones 1 and 20, respectively; no effect was observed in animals inoculated with the clone mixture. Also, a significant reduction in worm size and burden was observed for those sheep immunized with clone 1. Animals receiving clone 20, showed a significant reduction in egg output. Immunization induced a reduction of egg viability ranging from 58.92 to 82.11%. Furthermore, vaccinated animals produced clone-specific antibodies which were boosted after challenge with metacercariae of F. hepatica.

Protection and antibody isotype responses against Fasciola hepatica with specific antibody to pIII-displayed peptide mimotopes of cathepsin L1 in sheep

Fluke burdens, liver fluke size and biomass, fecal eggs counts, serum levels of hepatic enzymes and immune response were assessed in sheep immunized with peptide mimotopes of cathepsin L1 and challenged with Fasciola hepatica metacercariae. Twenty sheep were randomly allocated to four groups of five animals each; groups 1 and 2 were immunized at weeks 0 and 2 with mimotopes YVYRWVEAECVA and FSPAYLRDAALK, respectively; group 3 was immunized with wild-type M13KE phage and the control group received phosphate-buffered saline (PBS). All groups were challenged with 300 metacercariae at week 6 and slaughtered 16 weeks later. Groups 1 and 2 showed a reduction in fluke burden of 51.7% and 35.9%, respectively, when compared to the control group, but only the former was significant at the 5% level. Vaccinated animals showed a significant reduction in fluke length and width, wet weights and egg output. A significant diminution in the total biomass of parasites recovered was also observed in group 1. Levels of anti-phage total IgG increased rapidly within 2 weeks of the first immunization and were always significantly higher in groups 1 and 2 than in the infected control group. The fluke burden in group 1 was significantly correlated with IgG1 and total IgG. The vaccinated sheep with phage clones produced significantly high titres of IgG1 and IgG2 antibodies indicating a mixed Th1/Th2 response.

Proteolytic activity in Fasciola hepatica is reduced by the administration of cathepsin L mimotopes

The objective of this study was to assess the proteolytic activity of Fasciola hepatica cathepsins in liver sections from mice vaccinated with phage clones of cathepsin L mimotopes, using the film in situ zymography technique. Female BALB/c mice were immunized three times with 2.5 x 10¹¹ phage particles without adjuvant. Animals vaccinated with phage clones produced high titres of anti-mimotope antibodies and a significant reduction in fluke burden was observed following challenge with metacercariae of F. hepatica. The proteolytic activity in hepatic tissue was reduced after the immunization with phage clones.

Comparative Diagnosis of Serum IgG1 and Coproantigen ELISA for Fasciolosis Detection of Goats in Mexico

The objective of present study was to determine the prevalence of natural caprine fasciolosis in the Mixteca region of Mexico using coproantigen and serum IgG1 ELISA tests for comparative purposes. A total of 1070 serum and faecal samples were analyzed for IgG1 antibodies and coproantigens, using ELISA with E/S products as antigen and a monoclonal antibody-based sandwich ELISA. Prevalence of 73.46% was found using the serological ELISA and a percentage of 77.20 was found for coproantigen ELISA. The diagnostic sensitivity and specificity for serum ELISA were 86.7% and 96.4%, and for the coproantigen ELISA they were 93.1% and 97.8%, respectively. The seropositive samples were further categorized as low, medium, or high positivity. Results show a great proportion of low and medium positive goats when the serum ELISA test was used. Correlation coefficients between coproantigens and seropositivity were statistically significant (P < 0.01) for low seropositivity (r = 0.93) and medium seropositivity (r = 0.84). The accuracy of faecal antigen ELISA was higher compared to indirect ELISA serological test. Two ELISAs were shown to be useful for demonstrating the current status of F. hepatica infection in the endemic areas and can be employed in studies on epidemiology as well as anthelmintics treatment for preventing economic loss and the risk of transmission to humans.

Motility of Fasciola hepatica miracidia assessed with a computer-assisted sperm analyser.

The motility parameters of Fasciola hepatica miracidia were assessed at different temperatures and times post-hatching using computer-assisted sperm analysis. Eggs were incubated at 22 °C or 25 °C for 14 days. Five motion parameters were evaluated at different incubation temperatures up to 10 h post-hatching. No differences were observed in the percentage that hatched after incubation at the two different temperatures. However, the straight-line velocity of miracidia following incubation at 22 °C was significantly different from that observed at 25 °C (P< 0.01). All miracidium motion parameters at different post-hatching temperatures showed an overall decrease at the end of the experiment. Those miracidia hatching from eggs incubated at 25 °C had a higher velocity of 1673.3 μm/s compared with 1553.3 μm/s at 22 °C. Velocity parameters increased as the post-hatching temperature increased from 22 °C to 37 °C.

Efecto de la vacunación de cerdas y lechones contra circovirus porcino tipo 2 (PCV2) en la ganancia de peso y porcentaje de mortalidad en México

El objetivo del presente estudio fue evaluar la eficiencia de tres protocolos de vacunacion (cerdas, lechones o cerdas y lechones), sobre la media de la ganancia diaria de peso y porcentaje de mortalidad en lechones desde el parto hasta la finalizacion, en una granja con Sindrome Multisistemico de Desmedro Postdestete (PMWS). Durante el periodo posterior a la vacunacion (semana 3-22) de lechones, cerdas y lechones, estos mostraron un aumento significativo en la media de la ganancia diaria de peso y una reduccion significativa en el porcentaje de mortalidad. Las cerdas y lechones vacunados contra PCV2 para el periodo de estudio (semana 1-22), tuvieron un aumento significativo en la ganancia diaria de peso y una reduccion significativa en el porcentaje de mortalidad cuando se les comparo con el grupo control. Estos datos demuestran que la vacunacion contra PCV2 fue efectiva en mejorar el crecimiento y reducir el porcentaje de mortalidad en una piara infectada con PCV2.

Composición nutricional, consumo e índices de palatabilidad relativa de los frutos de tres acacias en la alimentación de ovejas y cabras

The aim of this study was to determine the nutritional composition of Acacia farnesiana , Acacia macilenta and Acacia cochliacantha fruits and determine...

Identificación de nuevos péptidos de una biblioteca de despliegue en fagos con un anticuerpo monoclonal específico a la proteína N del virus PRRS

El objetivo del estudio fue seleccionar de una biblioteca combinatoria de fagos filamentosos clonas que mimeticen la proteina N del virus del Sindrome Respiratorio y Reproductivo Porcino (PRRS) utilizando un anticuerpo monoclonal (SDOW17). Se utilizo una biblioteca combinatoria de fagos filamentosos (M13) que expone aleatoriamente peptidos de 7 aminoacidos en la region N-terminal fusionado con la proteina III. Para determinar el efecto del enriquecimiento despues de cada ronda de seleccion, los fagos eluidos fueron titulados; estos se incrementaron de 4,8 x 103 unidades formadoras de colonias (ufc) en la primera ronda a 3,2 x 105 ufc en la tercera. Despues de tres rondas de seleccion, 32 clonas fueron picadas al azar, cada clona individual fue amplificada, purificada y titulada. La reactividad de la union de las clonas a los anticuerpos anti-PRRS fue determinado utilizando un ELISA de fagos. El alineamiento de las clonas secuenciadas con la obtenida del GenBank, ubican a estas en la region aminoterminal y porcion media de la proteina N del vPRRS. La secuencia consenso de las 32 clonas seleccionadas fue NYRYQ. Las secuencias de los mimotopos fueron utilizadas para calcular los epitopos de la proteina N, mediante la herramienta bioinformatica del servidor Peptiope con el algoritmo PepSurf. Dos epitopos conformacionales contra el anticuerpo monoclonal antiproteina N fueron identificados, localizados en diferentes posiciones y presentados principalmente como helices a. Los mimotopos seleccionados y epitopos conformacionales podrian ser considerados informativos para el diagnostico de la enfermedad

Protección, función hepática y respuesta inmune humoral de ovinos vacunados con mimotopos de catepsina L1 y L2 infectados experimentalmente con Fasciola hepatica

Protection, liver function and humoral immune response were assessed in sheep vaccinated with mimotopes of cathepsin L1 and/or L2 and challenged with Fasciol...