Immune responses of swine to oral inoculation with embryonated eggs of Ascaris suum

Responses of swine to oral inoculation with embryonated eggs of Ascaris suum were monitored, using lymphocyte blastogenesis assays, indirect radioimmunoassays, and peripheral eosinophil counts (EC). Transient cell-mediated immune responses of peripheral lymphocytes were detected by lymphocyte blastogenesis assay as early as postinoculation day (PID) 2, but were rarely positive for consecutive samples taken at 2-day intervals. Humoral antibodies were first detected at PID 6 to 17 by indirect radioimmunoassays in the various experiments. Positive cutaneous delayed hypersensitivity reactions were observed when pigs were tested at 6 to 7 weeks after inoculation. Histopathologic examination verified infiltration of lymphocytes into the lesions. The EC increased as early as PID 4 to 7 and showed a secondary increase after the 2nd oral inoculation of eggs to as high as 11,400/mm3 (44% of the total WBC). Subsequently, EC decreased rapidly 14 days after the last inoculation of eggs.     

Immune responses of chickens to dietary protein antigens. I. Induction of systemic and intestinal immune responses following oral administration of soluble proteins in the absence of adjuvant

Oral administration of protein antigens in solution leads to the development of oral tolerance in most mammals but rarely so in the chicken. As dietary proteins are not expected to be immunogenic, the present study was undertaken to evaluate immunological consequences following oral exposure to protein antigens in chicks, and to determine whether or not this form of antigen is ignored. Chicks and turkey poults were fed solutions containing bovine serum albumin (BSA), porcine serum albumin, beta-lactoglobulin or bovine hemoglobin over a period of 6 days (25mg/chick/day). At different time points after feeding serum and bile were examined for presence of specific antibodies by ELISA. Surprisingly, the fed antigens induced robust antibody responses in the absence of added adjuvant. This immune response was further characterised to show that (1) a daily feeding regimen was more immunogenic than single dose feedings, (2) by using a daily feeding regimen, as little as 2mg/chick/day was fully immunogenic, (3) effective immunization was attained in chicks older than 10 day of age, (4) the main antibody class in the serum was IgG, and (5) high IgA levels were detected in the bile after booster feedings. These observations are difficult to reconcile with current concepts on peripheral tolerance to innocuous antigens, and indicate that the bird regulates tolerance and response in a manner different from that described in mammals.     

Hourly administration of GnRH to prepubertal gilts: endocrine and ovulatory responses from 70 to 190 days of age.

This study investigated the responsiveness of the pituitary-ovarian axis of prepubertal gilts to hourly injections (i.v.) with GnRH. Six gilts each at 70, 100, 150, and 190 d of age were assigned either to treatment with GnRH or saline. Treatments were given until gilts showed estrus or for 7 d, whichever came first. Hourly pulsing with GnRH resulted in gradually increasing concentrations of estradiol-17 beta (E2), a preovulatory surge of LH, and subsequently increased progesterone (P4) concentrations. The increase in serum P4 was preceded by ovulation and corpora lutea (CL) formation in two gilts 70 d of age and all older gilts. The interval (h) from start of GnRH treatment to peak E2 (88 +/- 3), peak LH (103 +/- 3), and concentrations of P4 greater than or equal to 1 ng/mL (144 +/- 4) did not differ (P greater than .50) for 18 gilts between 100 and 190 d of age. In two ovulating, 70-d-old gilts, the interval from onset of GnRH treatment to peak E2 (171 +/- 6), peak LH (186 +/- 0), and P4 greater than or equal to 1 ng/mL (216 +/- 4) was lengthened (P less than .001). Peak concentrations of E2 (pg/mL) were higher (P less than .01) at 190 d (48 +/- 2) and 150 d (49 +/- 2) than at younger ages and lower (P less than .01) in gilts 70 d of age (31 +/- 1) than in gilts 100 d of age (41 +/- 2). Peak LH (nanograms/milliliter) was higher (P less than .01) in gilts 100 d of age (12.7 +/- 6) than in older gilts. Concentrations of P4 were similar (P greater than .20) for all ovulating gilts. The number of CL (12.7 +/- .7) did not differ (P greater than .20) for 18 gilts 100 d of age or older but was higher (P less than .01) than that (4.5 +/- 1.1) for two gilts 70 d of age. Corresponding endocrine responses or ovulations were not observed in four 70-d-old gilts treated with GnRH or in gilts given saline. These findings indicate that the functional integration of the pituitary-ovarian axis is completed between 70 and 100 d of age. Hourly treatment with GnRH is an adequate stimulus to induce ovulation in prepubertal gilts as early as 70 d of age. Also, the number of follicles reaching ovulatory competency was similar (P greater than .20) in gilts between 100 and 190 d of age, when GnRH was given on a BW basis.     

Immune responses to oral vaccination with Salmonella-delivered avian pathogenic Escherichia coli antigens and protective efficacy against colibacillosis

In this study, the immune responses to and protective efficacy of a live attenuated Salmonella-delivered vaccine candidate secreting the papA, papG, iutA, and clpG antigens of Escherichia coli were evaluated against infection with avian pathogenic E. coli (APEC) in layer chickens. Primary vaccination was done at age 7 d and booster vaccination at age 5 wk. The levels of intestinal secretory immunoglobulin A specific to the 4 antigens were significantly higher in the vaccinated group than in the control group. A potent lymphocyte-proliferation response and increased levels of interferon-γ, interleukin-2, and interleukin-6 in the plasma and in culture supernatants of antigen-stimulated lymphocytes from the vaccinated group suggested significant induction of the cell-mediated immune response in this group compared with the control group. Upon challenge with a virulent APEC strain at 8 wk of age, the vaccinated group had no deaths, whereas the control group had a 15% mortality rate. In addition, the morbidity rate was significantly higher in the control group (55%) than in the vaccinated group (15%). Thus, giving primary and booster vaccination with the Salmonella-delivered APEC vaccine candidate significantly elevated both mucosal and cellular immune responses, which protected the chickens against colibacillosis.     

Immune response of sheep to oral and subcutaneous administration of live aromatic-dependent mutant of Salmonella typhimurium (SL1479)

The major objective of the present study was to determine whether oral immunization with a live aromatic-dependent strain of Salmonella typhimurium (SL1479) was capable of stimulating an intestinal immune response in sheep similar to that induced by combined intraperitoneal injection followed by oral boosting. The results showed that repeated oral immunization was incapable of stimulating an anti-flagella antibody containing cell (ACC) response in the lamina propria of the intestine even though primary oral administration of 5 x 10(9) live SL1479 gave rise to an ACC response in intestinal lymph which was predominantly of the IgM isotype. ACC reached a peak 9-10 days after oral administration when ACC comprised 0.5-1% of total lymphocytes in lymph. An ACC response of similar isotope specificity also occurred in popliteal prefemoral lymph of unprimed sheep following regional subcutaneous injection of SL1479. Oral administration of SL1479 to orally primed sheep did not reinvoke an ACC response in lymph although IgG1-ACC were observed in medullary cords of mesenteric lymph nodes of sheep 6-8 days after the booster dose of SL1479. The results suggest that the protective immunity elicited by oral administration of SL1479 cannot be attributed to induction of a local intestinal antibody production.     

Immune responses of sheep to louping-ill virus vaccine

The immune responses of sheep to single and double doses of commercially available louping-ill virus vaccine were examined. The susceptibility to challenge of sheep which had been vaccinated but showed a poor response was also investigated. Two injections of vaccine were required to provoke an adequate antibody response and maximum titres were obtained when there was an interval of two to eight weeks between injections. After challenge, viraemia could not be detected in animals with an antibody titre of 20 although increase in the concentration of humoral antibodies indicated that infection had occurred. Vaccinated but seronegative sheep and vaccinated animals with an antibody titre of 10 were also clinically resistant to the challenge, although circulation of virus was demonstrated. That vaccination had sensitised those animals to viral antigen was evident from the reduced viraemias, the early rise in humoral antibody titres and subsequent protection afforded compared to unvaccinated control animals. Thus, animals with minimal antibody titres after vaccination are protected, but it is recommended that vaccines eliciting the highest possible antibody responses will be the most useful under field conditions.     

Immune responses after local administration of IgY loaded-PLGA microspheres in gut-associated lymphoid tissue in pigs

Oral vaccination of large animals using PLGA MS (poly(D,L-lactide-co-glycolide)microspheres) appeared to be more challenging than immunization of mice. The purpose of this study was to deliver to GALT an immunogenic model protein (IgY), free or encapsulated by spray-drying in PLGA MS, and to evaluate systemic immune response in SPF Large White pigs. Pigs were surgically processed for local administration of IgY in three sets of experiments. In two sets of experiments, administration was locally performed in temporary ligatured intestinal segments, in jejunal Peyer's patches and in mesenteric lymph nodes. In the third experiment, pigs received IgY via an intestinal cannula. Total IgY-specific antibodies were detected in the sera of pigs after a single local immunization, but not in the sera of cannulated pigs. The study of IgG1 and IgG2 isotypes indicated that PLGA MS are able to elicit a combined serum IgG2/G1 response with a predominance of IgG1 response when locally administered. PLGA MS can be a potential oral delivery system for antigen but our results underlined the difficulty to immunize large animals like pigs. Transposition of data between small and large animals appears to be complex and suggests that physiological features need to be considered to increase intestinal availability of oral encapsulated vaccines.     

Immune responses to mycoplasma infections of the respiratory tract

Mycoplasmas are capable of causing respiratory disease in a number of species of animals. The pathogenicity of the mycoplasma species ranges from those that cause major disease outbreaks and economic loss to what might be considered the more highly evolved and successful parasites at the other end of the spectrum that survive for long periods in the host without being recognised and evicted. This prolonged colonisation of mucous membranes which is typical of many mycoplasmas is related to certain unique features of the mycoplasma and its interaction with the hosts immune system. An initial step in infection is the attachment of the mycoplasma to the epithelial lining of the respiratory tract. Lack of cell wall confers plasticity and may engender the intimate association of mycoplasma and host cell that has been noted. This in turn may favour persistence of the extracellular parasite. Before the specific immune response is produced avoidance of the non-specific immune mechanisms would clearly aid survival. Both passive (capsules) and active (toxic effects) mechanisms of avoiding phagocytosis have been proposed. Both humoral and cell mediated responses are generated by mycoplasma infections. The serum antibody response follows the usual course IgM, G and A. The indications of cell mediated immunity that have been reported include; delayed type hypersensitivity reactions, lymphocyte transformation responses and inhibition of macrophage migration. The concept that the pathological lesions are in a large part due to host reactivity is well accepted. The lung lesions may contain infiltrating and dividing lymphocytes some of which are producing specific antibody. Evidence for the lung lesion in some animals being partly due to the hosts cell mediated response has also been produced. The local immune response appears to be of greater relevance to immunity to infection than the systemic response, in general the association between local antibody and immunity is much better than for serum antibody. Of particular note is the high contribution of local IgG production, particularly in the lower respiratory tract. Attempts are now being made to use this increased understanding to produce effective killed vaccines that produce immune responses in the lung. Such studies will hopefully lead to the development of 'killed' vaccines that are effective. It can be urged that mycoplasmas would be less pathogenic if they did not produce an inflammatory response and some species have been shown to have an immunosuppressive effect. Such a property could affect the lesion, and hence pathogenicity, and also aid mycoplasma persistence.(ABSTRACT TRUNCATED AT 400 WORDS)     

Immune responses of breeding chickens to trivalent oil emulsion vaccines: responses to infectious bronchitis

Three similar flocks of broiler breeder parent chickens that had been given live infections bronchitis (IB) vaccines during rearing were injected at 20 weeks of age with three different oil emulsion vaccines: a commercial monovalent Newcastle disease (ND) vaccine (flock A); an experimental bivalent vaccine containing ND and infectious bursal disease (IBD) components (flock B); and an experimental trivalent vaccine containing ND, IBD and IB components (flock C). One week after vaccination 40 hens from flock A and 40 from flock C were taken to the laboratory and their egg yields individually recorded. At 37 weeks of age they were challenged by aerosol exposure to virulent IB virus. The egg production dropped significantly in the hens from flock A but not in the hens from flock C. On the farm, flock C showed a higher mean IB virus antibody titre four weeks after vaccination but titres rose in all three flocks indicating the presence of active IB virus infection. No differences in egg yields were found between the three farm flocks.     

Pharmacokinetics of voriconazole after oral and intravenous administration to horses

OBJECTIVE: To characterize pharmacokinetics of voriconazole in horses after oral and IV administration and determine the in vitro physicochemical characteristics of the drug that may affect oral absorption and tissue distribution. ANIMALS: 6 adult horses. PROCEDURES: Horses were administered voriconazole (1 mg/kg, IV, or 4 mg/kg, PO), and plasma concentrations were measured by use of high-performance liquid chromatography. In vitro plasma protein binding and the octanol:water partition coefficient were also assessed. RESULTS: Voriconazole was adequately absorbed after oral administration in horses, with a systemic bioavailability of 135.75 +/- 18.41%. The elimination half-life after a single orally administered dose was 13.11 +/- 2.85 hours, and the maximum plasma concentration was 2.43 +/- 0.4 microg/mL. Plasma protein binding was 31.68%, and the octanol:water partition coefficient was 64.69. No adverse reactions were detected during the study. CONCLUSIONS AND CLINICAL RELEVANCE: Voriconazole has excellent absorption after oral administration and a long half-life in horses. On the basis of the results of this study, it was concluded that administration of voriconazole at a dosage of 4 mg/kg, PO, every 24 hours will attain plasma concentrations adequate for treatment of horses with fungal infections for which the fungi have a minimum inhibitory concentration 相似文献   

Pharmacokinetics of fenbendazole following intravenous and oral administration to pigs

OBJECTIVE: To determine pharmacokinetics and metabolic patterns of fenbendazole after IV and oral administration to pigs. ANIMALS: 4 mixed-breed female pigs weighing 32 to 45 kg. PROCEDURE: Fenbendazole was administered IV at a dose of 1 mg/kg. One week later, it was administered orally at a dose of 5 mg/kg. Blood samples were collected for up to 72 hours after administration, and plasma concentrations of fenbendazole, oxfendazole, and fenbendazole sulfone were determined by use of high-pressure liquid chromatography. Plasma pharmacokinetics were determined by use of noncompartmental methods. RESULTS: Body clearance of fenbendazole after IV administration was 1.36 L/h/kg, volume of distribution at steady state was 3.35 L/kg, and mean residence time was 2.63 hours. After oral administration, peak plasma concentration of fenbendazole was 0.07 microg/ml, time to peak plasma concentration was 3.75 hours, and mean residence time was 15.15 hours. Bioavailability of fenbendazole was 27.1%. Oxfendazole was the major plasma metabolite, accounting for two-thirds of the total area under the plasma concentration versus time curve after IV and oral administration. Fenbendazole accounted for 8.4% of the total AUC after IV administration and 4.5% after oral administration. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicate that fenbendazole was rapidly eliminated from plasma of pigs. The drug was rapidly absorbed after oral administration, but systemic bioavailability was low.     

Pharmacokinetics and pharmacodynamics of furosemide after oral administration to horses

Furosemide is the most common diuretic drug used in horses. Furosemide is routinely administered as IV or IM bolus doses 3-4 times a day. Administration PO is often suggested as an alternative, even though documentation of absorption and efficacy in horses is lacking. This study was carried out in a randomized, crossover design and compared 8-hour urine volume among control horses that received placebo, horses that received furosemide at 1 mg/kg PO, and horses that received furosemide at 1 mg/kg IV. Blood samples for analysis of plasma furosemide concentrations, PCV, and total solids were obtained at specific time points from treated horses. Furosemide concentrations were determined by reversed-phase high-performance liquid chromatography with fluorescent detection. Systemic availability of furosemide PO was poor, erratic, and variable among horses. Median systemic bioavailability was 5.4% (25th percentile, 75th percentile: 3.5, 9.6). Horses that received furosemide IV produced 7.4 L (7.1, 7.7) of urine over the 8-hour period. The maximum plasma concentration of 0.03 microg/mL after administration PO was not sufficient to increase urine volume compared with control horses (1.2 L [1.0, 1.4] PO versus 1.2 L [1.0, 1.4] control). There was a mild decrease in urine specific gravity within 1-2 hours after administration of furosemide PO, and urine specific gravity was significantly lower in horses treated with furosemide PO compared with control horses at the 2-hour time point. Systemic availability of furosemide PO was poor and variable. Furosemide at 1 mg/kg PO did not induce diuresis in horses.     

Immune responses of teleost fish

In fish all the pre-requisites to mount a specific immune response are present, but the main differences from the mammalian system are that the secondary response is relatively minor and IgG is not present. In teleosts mainly IgM is present, and IgD has been recently described but its function is, as yet, unknown. However, different forms of fish IgM and its observed flexibility of structure may compensate for a lack of Ig class diversity. The innate immune response of teleosts is highly developed. Multiple forms of key constitutive and inducible components, such as lysozyme, C3, alpha2-macroglobulin and C-reactive protein, are present, and may enhance immune recognition. Low ambient temperature appears to have an impact on all aspects of the immune response, particularly the T-dependent specific immune response due to the non-adaptive lipid composition of T-cell membranes. Temperature effects on the nonspecific immune system are less well characterised, but there is evidence that low temperatures are also suppressive. Knowledge of immune system function becomes essential for disease prevention strategies such as the development of vaccines, selection for increased disease resistance and identification of genes suitable for trangenesis.     

Immune responses of cattle to experimental anti-Fasciola hepatica vaccines.

Fasciola hepatica infection of cattle and sheep is an important cause of clinical disease and production losses, and is controlled at present by a combination of chemotherapy and management measures. However, the prospects for the control of F. hepatica infection by vaccination are good, and we have previously shown substantial protection of cattle against experimental challenge infection following immunisation with a combination of the purified fluke-derived enzymes cathepsin L1 (CATL 1), cathepsin L2 (CATL 2) and fluke-derived Hb fraction (FHB). This and other recent studies have also demonstrated fundamental differences between protective and non-protective immune responses to liver fluke infection. In this present study we have further analysed the response of animals to liver fluke challenge following experimental vaccination. Calves were vaccinated with either CATL 2 plus FHB, or CATL 1 plus CATL 2. Partial protection against challenge infection was achieved in both vaccinated groups, with the greatest level of protection (55 per cent reduction in fluke burdens) recorded in the group vaccinated with CATL 1 plus CATL 2. This latter group also showed the greater level of lymphocyte proliferation and the greater production of gamma-INF in response to stimulation with fluke antigen in vitro following challenge. These results are significant in our attempts to characterise the elements within the immune response to vaccination which are protective.     

Pharmacokinetics of oestriol after repeated oral administration to dogs

The aim of the present study was to investigate the pharmacokinetics of oestriol in plasma in the dog after repeated oral administration of oestriol tablets, a preparation intended for the treatment of urinary incontinence in the bitch. The study was performed in six healthy, entire, adult female beagle dogs. The bitches were treated once daily with two tablets, containing 1 mg oestriol per tablet, for seven consecutive days (days 1-7). Blood samples were taken from the jugular vein before treatment, frequently on days 1, 3 and 7 of the treatment period and daily just before (C(trough)) and 1 h after dosing (C(t=1h)). During the washout period samples were taken at a 24 h interval up to four days post-treatment. Oestriol concentrations were determined in plasma by radioimmunoassay. Pharmacokinetic parameters, AUC, C(max) and t(max), were determined from the plasma concentration-time curves using non-compartmental methods. The between animal variation in C(max) and the AUC was high. Individual values of the C(max) varied from 206 pg/ml (day 1) to 1128 pg/ml (day 7) and the AUC(0-24h) from 789 pg x h/ml (day 1) to 5718 pg x h/ml (day 7). t(max) occurred within 1 h. The mean C(trough) value was slightly above the pre-treatment level ( 38+/-2 pg/ml vs. 18+/-5 pg/ml). Within 48 h after the last treatment the concentrations had returned to the pre-treatment values. C(max) and C(trough) did not increase during the treatment period, indicating that no accumulation occurred. A shoulder in the concentration-time curve around 8-12 h after treatment strongly suggested the existence of enterohepatic recirculation (EHR). The average relative contribution of the EHR to the AUC(0-24h) was estimated to be 22%, 38% and 44% on days 1, 3 and 7, respectively. These mean values were calculated from five animals per time point, because one dog failed to show EHR on days 1 and 3 and was therefore excluded from the calculations.     

分枝杆菌Hsp70对PCV2 Cap蛋白的免疫佐剂作用研究

为了研究分枝杆菌热休克蛋白(Hsp70)对猪圆环病毒2型(PCV2)Cap蛋白的免疫佐剂作用,以自聚肽ELK16为纯化标签,分别与Hsp70和PCV2 Cap基因融合后诱导表达,利用离心洗涤法进行融合蛋白纯化,获得了纯化的融合蛋白ELK16-Cap、ELK16-Hsp70和ELK16-Cap-Hsp70,其纯度高达95%、96%和85%,产量分别为92、84和83 mg/L;接着用PBS、ELK16-Cap、ELK16-Cap+弗氏不完全佐剂(IFA)、ELK16-Cap+ELK16-Hsp70和ELK16-Cap-Hsp70分别免疫小鼠,初免后21 d ELK16-Cap-Hsp70免疫组抗体水平达到最高;在二免后2周取免疫小鼠脾脏淋巴细胞,用试剂盒检测细胞因子表达,TNF-α浓度依次为588.55、802.55、995.55、1 382.55和1 719.55 pg/mL,IFN-γ浓度依次为46.30、92.22、155.56、470.37和518.15 pg/mL,IL-12浓度依次为14.72、28.06、20.83、31.39和34.72 pg/mL。这些研究结果表明,Hsp70对刺激PCV2 Cap蛋白ELISA抗体产生的作用优于IFA,但两者融合蛋白的刺激作用较强;与Cap蛋白融合的Hsp70对刺激TNF-α、IFN-γ和IL-12产生的作用较强,而ELK16-Hsp70+ELK16-Cap对3种细胞因子产生的刺激作用次之。