Hepatic lesions caused by migrating larvae of Ascaris suum in chickens

Group A consisted of chickens infected with a single dose of Ascaris suum and group B of chickens infected with two successive doses. At days 1, 3, 7, 14 and 21 after the first or second infection dose, six chickens from each group were sacrificed. In both groups, larvae were recovered from the livers on days 1, 3, and 7 and lungs on days 3 and 7. No larvae were detected in chickens on day 14. Clear white lesions were noticed only on the livers from chickens of group B at day 7 but had disappeared at day 14. A comparison with group B showed mild histological changes that developed relative to the livers from group A.     

Ascaris suum antigens incorporated into liposomes used to stimulate protection to migrating larvae

Four- to 8-week-old SPF pigs were immunized, using antigens of Ascaris suum incorporated into liposomes, via intestinal cannula or orally. Avridine was also incorporated in the liposomes in one experiment and interleukin-2 (IL-2) injected into pigs in another experiment. A priming dose of embryonate eggs (80-470 eggs/pig) were given in four of six experiments. Compared to control animals, the greatest protection of pigs to migrating ascarid larvae from a challenge dose of 10,000 embryonated eggs occurred where pigs received (1) a priming dose of eggs plus second-stage ascarid larval wall incorporated into liposomes, with or without avridine or IL-2, or (2) a priming dose of eggs plus ascarid intestinal aminopeptidase incorporated into liposomes with IL-2. The degree of protection was not statistically significant due, in part, to the variability in the responses of animals in the same treatment groups and the small number of animals per group. In general, only low titers of specific serum antibodies were detected and specific antibodies were not detected in the intestinal washing.     

Effect of fenbendazole and pyrantel tartrate on the induction of protective immunity in pigs naturally or experimentally infected with Ascaris suum

An experiment was conducted with 96 weanling pigs (avg initial wt 18.5 kg) divided into six treatment with two replicates of eight pigs each. Pigs in Treatments 1, 2 and 3 were penned in outside pens with dirt lots that previously were contaminated with A. suum ova to induce a natural ascaris infection. Pigs in Treatments 4, 5 and 6 were penned in an open-front building with solid concrete floors and were experimentally infected with 2,000 embryonated A. suum. ova on d 1, 15 and 29 of the experiment. Pigs in Treatments 1 and 4 were medicated with fenbendazole (FBZ, 3 mg/[kg BW.d]) for three consecutive days during three consecutive time periods. Pigs in Treatments 2 and 5 were medicated with pyrantel tartrate (PT, 106 mg/kg feed) for 28 d. Pigs in Treatments 3 and 6 served as infected, unmedicated controls. All pigs were challenged with 100 A. suum eggs 7 d after termination of the final FBZ treatment. All pigs were killed 66 d after challenge and worms were recovered. Fenbendazole treatment resulted in greater (P less than .07) average daily gain than PT treatment in pigs penned outside. Among inside pigs, FBZ treatment resulted in better (P less than .02) feed utilization than in controls. The FBZ and PT treatments reduced (P less than .03) the total number of A. suum, the length and weight of female ascarids and the length of male ascarids compared with controls. A natural continual infection with A. suum was less effective than experimental infection in inducing protective immunity in pigs.     

Protective immunity to Ascaris suum: analysis of swine peripheral blood cell subsets using monoclonal antibodies and flow cytometry

Outbred domestic swine or SLA inbred miniature swine were exposed to Ascaris suum either naturally on contaminated lots or by inoculation with UV-irradiated attenuated eggs. Both inbred and outbred swine developed virtually complete protection to a challenge of 10 000 eggs after natural exposure, but inbred swine were less resistant than outbred swine after UV-egg exposure. Flow cytometric analysis of peripheral blood mononuclear cells from these animals, performed to determine changes in cell subsets including helper T-cells, cytotoxic/suppressor T-cells, macrophages, and cells expressing class II major histocompatibility antigens, showed that both outbred and inbred swine had similar responses after parasite exposure. The levels of helper T-cells and cytotoxic/suppressor T-cells did not change after parasite exposure, while there was an appreciable but transient increase in macrophages only in those swine naturally exposed to A. suum. Swine exposed to A. suum, both naturally and by inoculation with UV-eggs, showed an increase in the amount of class II antigens detectable per cell. In a second set of experiments, outbred swine were exposed to A. suum naturally or by repeated experimental inoculation with different doses of normal eggs, and protective immunity and changes in blood cell subsets were determined. The greatest change in blood cell subsets was found at 3 and 5 weeks after initial parasite exposure, when macrophages were elevated moderately in a group of pigs inoculated every other day with 1000 eggs and markedly in a group that was naturally exposed; class II antigen expression was also increased during this period. These increases preceded peak serum antibody responses, which were lower in the naturally-exposed group relative to the experimentally-inoculated group. Both groups had high levels of protective immunity. This suggests than natural exposure to A. suum may activate cells and enhance specific immune responses to give high levels of protection.     

Partial characterization of the antigen recognized by a monoclonal antibody to Ascaris suum ovary extracts

A monoclonal antibody produced against ovary extracts from the worm Ascaris suum showed immunoreactivity against granules in the rachis and oocytes, the inner layer of the eggshell and the middle layer of some egg, but not against either ovary wall or uterus wall. Furthermore, the same antigens were detected on the body surface of migrated larva in guinea pig lung, whereas none were detected in adult male worm or adult female worm, except for the female reproductive organs. The ovary extracts were passed through an affinity column and the eluted fractions analyzed by SDS-PAGE, Western blotting and native-PAGE. Western blotting after SDS-PAGE detected chemiluminescence primarily as three bands of about 70, 78 and 90 kDa. However, Western blotting after native-PAGE of the partially purified ovary extracts demonstrated only one band at a position of about 230 kDa. LC-nanoESI-MS/MS analysis of protein band gel slices from silver-stained SDS-PAGE revealed one peptide sequence "ILVGLIGTNR", that matched only the hypothetical protein F14D2.8 of Caenorhabditis elegans (gi/7499081).     

Diseases produced by feline caliciviruses when administered to cats by aerosol or intranasal instillation.

Specific pathogen free cats were infected by two feline calicivirus isolates of different plaque type, an extra-large plaque (ep) former and a minute plaque (mp) former. A comparison was made of the disease produced when these isolates were administered by either aerosol or direct intranasal instillation. With both isolates, aerosol infection produced lesions and gave rise to virus replication throughout the respiratory tract. The effects of intranasal infection were more confined to the upper respiratory tract and oropharynx. By both routes of infection the disease produced by the mp virus was clinically and pathologically less severe than that produced by the ep virus.     

Pharmacokinetics of ceftriaxone administered by the intravenous, intramuscular or subcutaneous routes to dogs

The purpose of this study was to investigate the pharmacokinetics of ceftriaxone after single intravenous (i.v.), intramuscular (i.m.) and subcutaneous (s.c.) doses in healthy dogs. Six mongrel dogs received ceftriaxone (50 mg/kg) by each route in a three-way crossover design. Blood samples were collected in predetermined times after drug administration. Results are reported as mean +/- standard deviation (SD). Total body clearance (Cl(t)) and apparent volume of distribution (V(z)) for the i.v. route were 3.61 +/- 0.78 and 0.217 +/- 0.03 mL/kg, respectively. Terminal half-life harmonic mean (t(1/2 lambda)) was 0.88; 1.17 and 01.73 h for the i.v., i.m and s.c. routes, respectively. Mean peak serum concentration (C(max)) was 115.10 +/- 16.96 and 69.28 +/- 14.55 microg/mL for the i.m and s.c. routes, respectively. Time to reach C(max) (t(max)) was 0.54 +/- 0.24 and 1.29 +/- 00.64 h for the i.m and s.c. routes, respectively. Mean absorption time (MAT) was 1.02 +/- 0.64 and 2.23 +/- 00.73 h for the i.m and s.c. routes, respectively. Bioavailability was 102 +/- 27 and 106 +/- 14% for the i.m and s.c. routes, respectively. Statistically significant differences were determined in C(max), t(max), MAT and t(1/2 lambda) of s.c. administered ceftriaxone when compared with the i.v and i.m. routes. These findings suggest that once or twice s.c. or i.m. daily administered ceftriaxone should be adequate to treat most susceptible infections in dogs.     

The intestinal and serum humoral immune response of mice to orally administered antigens in liposomes: II. The response to liposome-entrapped bacterial proteins.

Effective oral adjuvants are needed to improve the intestinal immune responses to oral vaccines that are based on relatively low molecular weight antigens refined from veterinary pathogens. Liposomes prepared by different methods and composed of phospholipids of varying transition temperature were used to entrap cholera toxin (CT) and fed to mice. No significant increase in the intestinal antibody nor the serum IgA antibody response was detected but levels of serum IgG anti-CT antibody were significantly elevated in the group fed CT in phosphatidylcholine-based liposomes. Levels of antibody were significantly reduced in the groups fed CT in dipalmitoylphosphatidylcholine liposomes. Escherichia coli wall extract (ECWE) entrapped in certain liposome types and fed to mice elicited significantly increased serum anti-ECWE antibody responses but intestinal antibody responses were insignificantly different from the controls. These results suggest that orally administered liposomes fail to act as potent intestinal adjuvants for the entrapped antigens of bacterial origin used in this study.     

The intestinal and serum humoral immune response of mice to systemically and orally administered antigens in liposomes: I. The response to liposome-entrapped soluble proteins.

The development of oral vaccines is of great importance in veterinary medicine and new adjuvants and carriers are essential to this aim. Liposomes are effective systemic adjuvants but the relatively little data on their potential as oral adjuvants is inconclusive. Liposomes containing ovalbumin (OA) were effective adjuvants when administered intraperitoneally to mice. Feeding mice with OA or keyhole limpet haemocyanin in liposomes in a series of priming and boosting regimes failed to elicit any significant increase in serum or intestinal antibody response compared with feeding the free antigen. Oral tolerance induction to systemic challenge was also unaffected by OA entrapment in liposomes. In vitro liposome stability assays at 37 degrees C demonstrated a substantial resistance to disruption in the presence of acidic stomach contents. However, the addition of bile caused a rapid and profound release of protein marker from the liposomes. The rate and degree of disruption was influenced by the type of phospholipid used. These results suggest that liposomes may be useful as carriers for orally administered compounds but they are ineffective as adjuvants for the non-particulate, naturally weak immunogens used in this study.     

Susceptibility and immune responses of zebu and taurine cattle of West Africa to infection with Trypanosoma congolense transmitted by Glossina morsitans centralis

Following tsetse-transmitted infection with Trypanosoma congolense, major differences in development of localised skin reactions, the ability to control parasitaemia, the degree of anaemia and in antibody response to trypanosomes were found between the reputedly trypanotolerant breeds of cattle (N'Dama, N'Dama/Baoule crosses, Baoule) and the trypanosusceptible West African Zebu. The local skin reactions that developed in the Zebu were large and severe while those that occurred in the other breeds were smaller and less severe or mild. The timing of appearance of parasitaemia and the height of the first peaks were similar in all the animals, but the Zebu were less able to control subsequent waves of parasitaemia. Possibly reflecting these events, it was only in the Zebu that significant anaemia developed. Neutralizing antibody against homologous metacyclic trypanosomes developed between 14 to 18 days after infection in all breeds of cattle; however, marked differences were found when antibody to trypanosomes derived from first peak parasitaemias were tested in the Zebu and Baoule. Neutralizing antibody against these parasites appeared in the Baoule on day 24 but were not detected in Zebu until day 51. Furthermore, the antibody titres were 3 log2 higher in the Baoule. It was concluded that the trypanotolerance exhibited by the West African taurine cattle might be related to a) their ability to control trypanosome numbers in the skin and in the bloodstream, an outcome that was possibly brought about by the earlier and superior immune response and b) failure to develop anaemia which might be associated with their capacity to control parasitaemia.     

口服黄芪多糖增强肠道黏膜免疫及其对口蹄疫疫苗免疫的影响

将40只小鼠随机分为2组,一组小鼠灌服黄芪多糖水溶液,另一组灌服生理盐水为对照组,给药后每周从各组随机取5只小鼠,分离脾淋巴细胞进行淋巴细胞增殖试验,并观察十二指肠黏膜上皮内淋巴细胞(IELs)以及上皮固有层的IgA+细胞数;将24只小鼠随机分为4组,各小鼠分2次,间隔2周注射口蹄疫(FMD)疫苗,其中1~3组的小鼠在疫苗免疫前灌服不同剂量的黄芪多糖,第4组小鼠灌服生理盐水作为对照。二免后1~5周,每周采血,检测血清IgG及其亚类。结果表明,小鼠口服黄芪多糖能显著促进小鼠淋巴细胞对刀豆蛋白A(ConA)和脂多糖(LPS)的刺激反应,并增加十二指肠IELs和固有层IgA+细胞数量;口服黄芪多糖后接种FMD疫苗,能够显著增强血清FMD特异性IgG及其亚类水平。     

Trials to induce protective immunity in mice and sheep by application of protoscolex and hydatid fluid antigen or whole body antigen of Echinococcus granulosus

In the current study, soluble proteins prepared from 200 mature Echinococcus granulosus and protoscolices of sheep hydatid cysts were applied to immunize sheep and mice respectively. The samples were mechanically homogenized in a blender, sonicated and the final yield was maintained at -20 degrees C until analysis. Hydatid fluid was isolated from liver or lung of sheep under sterile conditions. In the first experiment, 15 mice were randomly allocated to three groups of five mice each. Each mouse in groups 1 and 2 was immunized with 100 microg of hydatid fluid and protoscolex proteins in 100 microl of phosphate-buffered saline (PBS) and emulsified with an equal volume of Freund's complete adjuvant (FCA) respectively. The mice of group 3 were immunized with adjuvant in PBS. The mice were boosted 4 weeks after the first vaccination with the same preparation except that FCA was replaced by Freund's incomplete adjuvant (FIA). In the second experiment, eight male or female lambs 4-6 months of age, were allocated to two groups of four lambs each. Each lamb in the test group was vaccinated subcutaneously in the neck with a 2-ml dose of vaccine (1 mg of whole body protein of E. granulosus dissolved in 1 ml of PBS plus 1 ml of FCA). Control lambs were vaccinated with adjuvant in PBS. Lambs were boosted the same way as in the first experiment. Three weeks after the second vaccination, each mouse and lamb received a challenge infection with 2000 protoscolices intraperitoneally and each lamb additionally received 10 gravid E. granulosus. All mice and sheep were killed after 7 months and examined for hydatid cysts. In these studies, protective immunity was induced in mice with protoscolex protein and with hydatid fluid, and in sheep with whole-body homogenate of E. granulosus and the levels of protection afforded were found to be 72.1, 82.6 and 90.9% respectively.