To evaluate an immunization procedure using antigens from Haematobia irritans intestine (AgHiI), four bovines (group I) were inoculated with AgHiI mixed with Freund's incomplete adjuvant containing Lactobacillus casei, three bovines (group II) received AgHiI, and three bovines (group III) received saline solution. At day 35, blood was collected from each animal to feed H. irritans flies. There was no difference in the fly mortality observed in the three groups. The percentage of reduction of eggs oviposited by each female in 8 days (%RE), as compared with group III, was 29.45 for group I and 11.02 for group II. Antibody levels (AbL) to AgHiI were higher in group I than in groups II and III. A high correlation between %RE and AbL was observed.
"These include membrane components of the epithelium or peritrophic matrix components and have resulted in highly effective immunization of the hosts. Examples include the tick Boophilus microplus (de la Fuente and Kocan, 2006) and the blood-feeding nematode H. contortus (LeJambre et al., 2008) and the horn fly (Bautista et al., 2004). Use of hidden antigens provides an opportunity to avoid the immuno-modulatory effect of excretory/secretory antigens . "
[Show abstract][Hide abstract] ABSTRACT: Soluble fractions of Hypoderma lineatum third instar fat body, haemocytes and haemolymph were formulated with Quil A and used to immunize four groups of calves while a fifth group remained untreated. Calves received two subcutaneous injections of the soluble fractions, or adjuvant only delivered two weeks apart. Two weeks after the last injection the calves were exposed to 50 newly hatched larvae of H. lineatum which were placed on the skin and allowed to penetrate. Survival of larval stages was monitored by weekly palpation and collection of emergent third instars. Antibody responses to the immunogens were evaluated by immunoblots and following infestation antibody responses to first instar antigens were evaluated by an ELISA. Non-immunized calves and calves injected with adjuvant were all palpation positive for cattle grubs. In groups immunized with fat body, haemocyte and haemolymph components 100%, 33% and 33% were palpation positive for grubs respectively. First instar mortality, as reflected in palpable grubs, was high in the groups receiving injections with tissue components (99.3%, 95.1%, 95.8%, 83.9 and 80.4% mortality for those groups receiving fat body, haemocyte, haemolymph, adjuvant or control respectively). Second and third instar mortality was also higher in the immunized groups (100.0%, 91.7%, 91.7% for fat body, haemocyte, and haemolymph respectively) in comparison to the adjuvant only (14.0%) and unvaccinated (33.3%) groups. No viable flies emerged from pupae originating from larvae emergent from any of the immunized groups. Calves receiving the tissue extracts developed antibodies to several protein components following the second immunization which were still present 13 weeks post-infestation. Several proteins appeared to be common among the three tissue extracts and were recognized by antibodies from the immunized calves. All groups of calves became positive for antibodies to first instar antigens, although in some immunized calves the antibodies were transient.
[Show abstract][Hide abstract] ABSTRACT: Ectoparasites of livestock are of great economic and social importance but their effective control remains difficult. The feasibility of vaccination as a novel control measure was established over a decade ago with the commercial release of a recombinant vaccine against the cattle tick Boophilus microplus. Since then, research has continued on ticks and other ectoparasites. While some ectoparasite species will undoubtedly be refractory to immunological control, for others there has been a steady accumulation of knowledge of partially protective antigens, now accelerating through the application of genomic technologies. Nevertheless, progress towards usable, commercially available vaccines has been limited by a number of factors. The number of highly effective antigens is still very small. Although some classes of antigen have been investigated in more detail than others, we have no systematic knowledge of what distinguishes an effective antigen. Much hope has been placed on the potential of multi-antigen mixtures to deliver the efficacy required of a successful vaccine but with little experimental evidence. The application of current knowledge across parasite and host species needs to be explored but little has been done. In most cases, the path to commercial delivery is uncertain. Although many constraints and challenges remain, the need for vaccines and our capacity to develop them can only increase.
[Show abstract][Hide abstract] ABSTRACT: El objetivo del presente estudio fue evaluar el efecto de los anticuerpos presentes en la sangre de Bos taurus inmunizado con antígenos ocultos del intestino de Stomoxys calcitrans sobre la supervivencia de las moscas adultas y sobre la oviposición. Se obtuvieron cinco mil intestinos de S. calcitrans alimentadas con sangre normal de bovino, para preparar un extracto antigénico (AgIn-Sc). Posteriormente, un bovino fue inmunizado con AgIn-Sc en adyuvante incompleto de Freund los días 0, 14, 21, 28, 35 y 40. Otro bovino (testigo) fue inoculado con solución salina en las mismas fechas. A los días 40 y 50 posinmunización se recolectó sangre periférica de los dos animales; una parte se utilizó para obtener suero, que se congeló en alícuotas a ¿70ºC hasta su uso, y la otra se conservó en citrato de sodio al 2% a 4ºC. Con esta última se alimentó durante una semana a grupos de 200 moscas S. calcitrans recién emergidas/bovino, las cuales se mantuvieron bajo condiciones de laboratorio. Durante los días 40 y 50 posinmunización se practicaron tres observaciones diarias durante una semana para evaluar la mortalidad de las moscas y contar el número de huevos depositados (HD). Se observó que no hubo un efecto dañino de la sangre del animal inmunizado sobre la supervivencia de las moscas, pero sí sobre la oviposición. Se apreció una disminución signifi cativa en el número total de HD, que osciló entre 29% (P < 0.05, sangre del día 40) y 65% (P < 0.01, sangre del día 50) con respecto al número de HD por las moscas que se alimentaron de sangre del animal testigo. Mediante ELISA se obtuvieron los títulos de anticuerpos IgG antiintestino en el suero del animal inmunizado: 1:1280 y 1:2560 para los días 40 y 50, respectivamente; mientras que en los mismos días, el suero del bovino testigo fue negativo a dichos anticuerpos. Por Western blot, el suero del día 50 reconoció siete componentes en el AgIn- Sc con pesos moleculares aparentes que oscilaron entre 35 y 205 kilodaltones. Con base en estos resultados se concluye que e
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