首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 62 毫秒
1.
Cattle exposed to their third consecutive warble (Hypoderma lineatum and H. bovis) infestation had significantly reduced apparent and accumulative grub populations and produced significantly fewer grubs than animals exposed to their first infestation. These resistant animals had enhanced reactivity to mitogens (concanavalin A (con A) and pokeweed) upon reinfestation and a strong antigen-specific response at 2 months post-infestation. Their responsiveness to con A and antigen was also enhanced at 7 months post-infestation when grubs appeared in the backs, and the response to antigen continued at 10 months post-infestation. Responsiveness to mitogens in previously uninfested animals was similar to the control response throughout the infestation apart from the suppression of the con A response at 7 months post-infestation. These animals finally responded to antigen at 10 months post-infestation. These results suggest that acquired resistance to hypodermosis has a cellular basis with participation of both B- and T-cell components.  相似文献   

2.
An antigen capture assay for the detection of circulating hypodermin C was developed for diagnosis of hypodermosis. A murine monoclonal antibody to recombinant hypodermin C was raised using rapid immunization and a one-step hybridization-cloning technique. A highly reactive, specific monoclonal antibody was tested using sera spiked with known quantities of purified, native hypodermin C or with recombinant hypodermin C. Sensitivity of 96.4% and specificity of 95.6% for the antigen capture assay was assessed using a panel of sera from animals unexposed to cattle grubs and from cattle with palpation proven cattle grub infestations. Data from this panel of sera was used to establish the cut-off OD for further testing. The kinetics of circulating hypodermin C was assessed using the assay in three groups of cattle artificially infested with 50, 100 or 200 first instar Hypoderma lineatum. Antigen was first detected approximately 6 weeks after infestation. The amount of antigen detected increased in each group of animals reaching peaks at different times in each group. Levels of antigen fell quickly following arrival of grubs at the back and completion of the molt to second instar.  相似文献   

3.
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.  相似文献   

4.
Cattle infested with the common cattle grub, Hypoderma lineatum (Villers) develop specific humoral antibodies and a cellular immune reaction, defined by delayed-type hypersensitivity, to purified H. lineatum proteins. This investigation was designed to study the antigen-specific bovine lymphocyte response to hypodermin A (HyA), a serine protease of larval first-instar H. lineatum. Calves were vaccinated with either native or denatured HyA, and challenge-infested with H. lineatum. The kinetic development of a cellular immune response to HyA was monitored during vaccination and infestation. The HyA-specific responses were highly variable and weak during vaccination and infestation. Although HyA-specific lymphocyte blastogenic responses were observed, no correlation was noted between the magnitude of antigen-specific, peripheral lymphocyte proliferation and larval mortality. In striking contrast to responses observed during infestation, intense HyA-specific lymphocyte responses were observed with 3 calves 6 months after recovery from infestation. In addition, those responses were further heightened by a 250 micrograms booster injection of pure HyA.  相似文献   

5.
Sero-prevalence of cattle grubs (Diptera: Oestridae) was monitored on two large western Canadian ranches from 1992 to 1999. One ranch has had a long-term programme for therapeutic control of cattle grubs as required by legislation in the province of Alberta. The other ranch, located in southeast Saskatchewan, has not used any treatment for grub control for an extended period of time. Serum from calves was tested each fall for the presence of antibodies to Hypoderma spp. using an ELISA. Percent positive sera on the Ranch 1 ranged from 8.0 to 73.3%. There was substantial variation among years and among two separate herds maintained on the ranch. Percent infested calves on the Ranch 2 ranged from 76.5 to 99.0%. Improved surveillance for cattle grubs using serological techniques is the only effective means to monitor the status of this important parasite.  相似文献   

6.
The potential for cross-transmission of Hypoderma lineatum from cattle to domestic goats (Capra hircus) was examined using artificial infestation techniques. Two routes of infestation, subcutaneous injection and dermal penetration, were used to expose goats to newly hatched first instars. Presence of antibodies and appearance of circulating antigen (hypodermin C) were evaluated at selected intervals for up to 40 weeks post-infestation. In addition, immunoblots against H. lineatum first-instar proteins were conducted using sera taken at 10 weeks post-infestation. Goats were palpated for the presence of developing larvae at sub-dermal sites beginning at week 30 pi. No developing larvae were palpated at any time, regardless of the route of infestation nor was circulating antigen detected in any infested goats. Antibodies were present at weeks 6 and 10 and week 27 pi in both infested groups. Immunoblots indicated all infested goats produced antibodies to first instar H. lineatum antigens. H. lineatum appears to be incapable of completing development in domestic goats although the transient appearance of ELISA detectable antibodies and the presence of bands on immunoblots suggests that at least some larvae survive long-enough to engender a humoural response. The host specificity of H. lineatum is discussed in light of the general concepts of host-parasite relationships of oestrids.  相似文献   

7.
An antigen capture ELISA, using a murine monoclonal antibody recognising recombinant hypodermin C (rHyC), was used to evaluate the influence of early treatment with eprinomectin (Eprinex) or fenthion (Spotton) on the kinetics of circulating hypodermin C in calves naturally infested with Hypoderma lineatum. No viable larvae were collected from treated animals, whereas a variable number of warbles were found in control animals. Treatment provoked a decrease in circulating HyC levels that was significant 9 days post-treatment (p.t.). Circulating antigen levels in the treated cattle remained detectable for approximately 99 days p.t. In contrast, control animals had no detectable antigen at 64 days p.t., 42 days earlier than in the treated animals. These results suggest that larvae were either gradually killed, resulting in slow release of antigen or they were encapsulated, leading to the slow liberation of antigen. Kinetics of circulating HyC did not differ among the two insecticide treatments. Antibodies persisted, in all groups, throughout the 120-day study. These results suggest that the antigen capture ELISA will be useful as a technique for detecting successful treatment of cattle grub infestations and for the detection of new infestations in previously infested cattle.  相似文献   

8.
Protein species found in soluble crude extracts of Hypoderma lineatum (common cattle grub) 1st-instar larvae (HL1) were separated by non-denaturing and denaturing polyacrylamide gel electrophoresis (PAGE) and analyzed for antigenicity by Western blotting using serum from H. lineatum-infested and vaccinated cattle. All HL1 proteins resolved by non-denaturing PAGE were found to be antigenic in the infested bovine host. Treatment of the proteins with sodium dodecyl sulfate and 2-mercaptoethanol destroyed the ability of hypodermin B and the Peak 2 proteins from DEAE-ion exchange HPLC to be bound by antibody. The principal proteins, hypodermin A and hypodermin C (collagenase), appear to be the most immunogenic of the larval proteins. Although having similar amino acid composition, hypodermin A did not appear to share an antigenic epitope with the most prevalent protein, hypodermin C. These results may allow for the selection of proteins to be used in vaccine trials and studies of protective immunological mechanisms associated with acquired resistance to H. lineatum infestation in the bovine host.  相似文献   

9.
A DNA vaccine expressing glycoprotein C (gC) of bovine herpesvirus-1 (BHV-1) was evaluated for inducing immunity in bovines. The plasmid encoding gC of BHV-1 was injected six times intramuscularly or intradermally into calves at monthly intervals. After immunization by both routes neutralizing antibody and lymphoproliferative responses developed. The responses in the intradermally immunized calves were better than those in calves immunized intramuscularly. However, the intradermal (i.d.) route was found to be less efficacious when protection against BHV-1 challenge was compared. Following intranasal BHV-1 challenge, all immunized calves demonstrated a rise in IgG antibody titre on day 3, indicating an anamnestic response. The control non-immunized calf developed a neutralizing antibody response on day 7 post-challenge. The immunized calves showed a slight rise in temperature and mild clinical symptoms after challenge. The intramuscularly immunized calves showed earlier clearance of challenge virus compared with intradermally immunized calves. These results indicate that DNA immunization with gC could induce neutralizing antibody and lymphoproliferative responses with BHV-1 responsive memory B cells in bovines. However, the immunity developed was not sufficient to protect calves completely from BHV-1 challenge.  相似文献   

10.
Two commercially available synthetic adjuvant systems, trehalose dimycolate (TDM) and TDM + monophosphoryl lipid A (MPL), were compared with Freund complete adjuvant (FCA) for the ability to stimulate antibody production in New Zealand White rabbits (Oryctolagus cuniculus). In addition, each animal was evaluated for adverse reactions. The antigen, rat liver microsomal epoxide hydrolase, was administered SC emulsified with FCA, TDM, or TDM + MPL. Serum antibody titers were stimulated with all 3 adjuvant-antigen combinations. The highest titer was produced by use of FCA; TDM + MPL produced an intermediate response, and TDM produced the lowest titer. All of the rabbits immunized with FCA developed sterile subcutaneous abscesses. Rabbits immunized with TDM or TDM + MPL developed no abscesses, and only slight reactions at the injection site. The synthetic adjuvant system TDM + MPL is recommended for use in rabbits, considering its adequate stimulation of antibody production with minimal adverse reactions.  相似文献   

11.
The feasibility of immunizing calves against Hypoderma lineatum and H. bovis with a crude H. lineatum larval extract or culture-derived antigen was investigated. Larval survival was followed through pupation. Grub appearance in the backs of both of the immunized groups was found to be 50% of that in the control groups. First appearance of H. bovis was significantly retarded in both immunized groups; however, H. lineatum was unaffected. Duration of H. bovis dropping was also shorter in animals receiving crude extract than in controls while duration of dropping of H. lineatum was not influenced by immunization. Survival of H. lineatum larvae to pupation was significantly reduced in animals immunized with crude larval extract, but not in those receiving culture-derived antigen. H. bovis survival was reduced by both treatments.  相似文献   

12.
本研究拟评估仔猪接种猪繁殖与呼吸综合征减毒活疫苗对猪圆环病毒病疫苗、猪瘟疫苗免疫的干扰情况,并分析不同免疫方式对仔猪生长性能的影响,以期为探究PRRSV减毒活疫苗与PCV2、CSF疫苗的联合免疫提供数据参考。本研究先以100头仔猪为研究对象,将其随机分为A、B、C、D 4组。其中A组仔猪免疫PRRSV减毒活疫苗7 d后免疫PCV2疫苗;B组仔猪同期分点注射PRRSV减毒活疫苗和PCV2疫苗;C组仔猪仅免疫PCV2疫苗;D组仔猪仅免疫PRRSV减毒活疫苗。另外再筛选100头仔猪,随机分为E、F、G、H 4组。E组仔猪于免疫PRRSV减毒活疫苗12 d后免疫CSF疫苗;F组仔猪同期分点注射PRRSV减毒活疫苗和CSF疫苗;G组仔猪仅免疫CSF疫苗;H组仔猪仅免疫PRRSV减毒活疫苗。免疫4周后,测定仔猪血清中相关抗体水平。同时,称量免疫前后各组仔猪的体重,计算不同免疫方案仔猪的平均日增重。结果表明：A~D组中, A组和B组仔猪在免疫4周后均产生了较高水平的PRRSV及PCV2抗体,且A组抗体水平略高于B组。C组仔猪仅产生了PCV2抗体,D组仔猪产生了较高水平的PRRSV抗体。E~H 4组中,E组和F组仔猪均产生了较高水平的PRRSV及CSFV抗体。G组仔猪仅产生了高水平的CSFV抗体,H组仔猪仅产生了高水平的PRRSV抗体。A、B、C、D 4组中B组仔猪的平均日增重最高;而E、F、G、H 4组中E组仔猪的平均日增重显著高于其他3组。PRRSV减毒活疫苗与PCV2疫苗或CSF疫苗同期分点免疫、免疫PRRSV减毒活疫苗一段时间后再免疫PCV2或CSF疫苗均能诱导仔猪产生高水平的抗体;在体液免疫方面,PRRSV减毒活疫苗免疫与否均未对另外二种疫苗表现出明显的干扰作用。在仔猪28日龄时同期分点免疫PRRSV减毒活疫苗与PCV2疫苗,12 d后再免疫CSF疫苗的免疫方案不仅能诱导仔猪产生高水平抗体,还可以使仔猪具备较高的平均日增重。  相似文献   

13.
The serum antibody response of calves vaccinated against infectious bovine rhinotracheitis by the intramuscular route was compared to calves vaccinated subcutaneously. Immunological response in the calves as determined by serum neutralization tests was highly variable; however, a significantly greater percentage (87.5%) of the calves inoculated subcutaneously responded to vaccination by producing a four-week post-vaccinal serum titer of two or higher as compared to only 47.8% of the calves that were vaccinated intramuscularly. Of those calves that were vaccinated a second time, all maintained or had produced titers of two or higher within four weeks after the second immunization. However, the existing circulating serum antibody titers resulting from the first vaccination of nine of 22 calves were lowered by repeat vaccination.  相似文献   

14.
Serologic responses in 61 calves 3 to 34 days of age following immunization with bacterins containing a heat-killed rough mutant, Escherichia coli 0111:B4 (strain J5) were determined by an enzyme-linked immunosorbent assay specific for the IgG isotype. Administration of either heat-killed bacteria or oil-based adjuvants alone failed to enhance serologic recognition of common core antigens when comparing to nonvaccinate controls. Increased titers were uniquely and specifically limited to calves receiving the antigen in an oil emulsion. In a second experiment, age and initial, passively acquired titer recognizing the vaccinal antigen were not found to have any effect on the magnitude of the humoral response of 57 calves following immunization.  相似文献   

15.
Previous findings, viz. that mice can be successfully immunized against infection with Salmonella dublin with either live or inactivated vaccine, were confirmed. Immunity lasted for at least 12 weeks in mice which had been immunized with inactivated alum-precipitated vaccine. The immunogenicity of inactivated vaccine gradually decreased on storage at 4 degrees C, but this was only detectable if a single injection was used for immunization: 2 injections virtually eliminated this phenomenon. The immunogenicity of live vaccine in mice was not enhanced by levamizole or the simultaneous injection of inactivated organisms. Both live and inactivated vaccines provided immunity in calves. A single injection of lyophilized vaccine, prepared from live rough Salmonella dublin strain (HB 1/17),protected 3 out of 6 calves, while 2 injections of a formalin-inactivated, alum-precipated vaccine, containing 1% packed cells of S. dublin strain 2652 V, protected 5 out of 6 calves against intraduodenal challenge with 2 x 10(9), S. dublin strain 2652 V. Two calves which had been immunized with an inactivated oil adjuvant vaccine were also solidly immune to this challenge. Serum antibody response in calves was poor when measured by the tube agglutination and the haemagglutination tests. Similarly, the sera had only marginal protective values when tested by means of a passive protection test in mice. Antibody titres alone are not a valid measure therefore, for the immune status of immunized animals.  相似文献   

16.
Sera from calves immunized with Yersinia enterocolitica serotypes O:9 or O:16 were tested by indirect enzyme linked immunosorbent assay (ELISA) using lipopolysaccharide (LPS) preparations from Brucella abortus or Y. enterocolitica O:9 or O:16 for their antibody content of the IgG1 or IgG2 subclasses. High IgG1 responses were present with the three antigens in both groups although some individual variations between animals were noted. The IgG2 responses were modest and in some cases not above background 'noise'. Thus IgG2 antibody was not measurable in sera from serotype O:9 injected calves when using serotype O:16 LPS or in serotype O:16 injected calves when using B. abortus or serotype O:9 LPSs. A competitive ELISA using B. abortus O-polysaccharide and a monoclonal antibody to B. abortus LPS (initially designed to differentiate the antibody responses of cattle naturally infected with B. abortus from those vaccinated with strain 19) was used on sera from both groups of calves. Using this test, no antibody was detected in the group immunized with serotype O:16 and except for one animal in the serotype O:9 immunized group, only low levels of antibody were transiently in evidence. One animal in this group responded with quite high levels of competing antibody which, however, declined towards the end of the test period. The competitive ELISA may prove a useful serological tool for differentiating vaccinal and field infection titers to B. abortus and also to eliminate cross-reactions observed with Y. enterocolitica serotypes.  相似文献   

17.
The aim of this study was to compare the immune responses to live Neospora caninum tachyzoites and N. caninum native antigens formulated with immune stimulating complexes matrix (ISCOM-matrix) in calves. Fifteen calves were used in this study: 3 were intravenously inoculated with 1 × 10(8) live tachyzoites (Group A), 3 were inoculated twice with N. caninum native antigens formulated with ISCOMs (Group B); 3 with N. caninum native antigens in phosphate-buffered saline (PBS) (Group C); 3 received ISCOM-matrix (ISCOMs without antigen) (Group D) and 3 were negative controls receiving PBS (Group E). The last four groups were inoculated subcutaneously. The specific total IgG and its subtypes were analyzed by an indirect enzyme-linked immunosorbent assays (ELISAs) and by Western blot. IFN-γ levels in plasma was quantified using a commercial kit. All calves were challenged intravenously with 1 × 10(8) live tachyzoites at week 11 after receiving the first dose. Parasitemia was assessed in plasma samples by semi-nested PCR. Neospora-specific antibodies were detected in animals from Groups A and B in the week 2 after inoculation. The ELISA OD values were higher in Group B compared with Group A from weeks 6 to 11 (P<0.05). Analysis of the subisotype specific antibodies in experimentally infected calves revealed a predominant IgG(2) response; however, a predominant IgG(1) response was observed in animals inoculated with N. caninum native antigens formulated with ISCOM-matrix. Control calves remained seronegative until challenge infection. The pattern of bands by Western blot was similar when testing sera from animals in Groups A and B. The levels of IFN-γ production after respective immunization schedules were similar between Groups A and B. Neospora-DNA was detected in plasma samples shortly after intravenous challenge in calves from all groups including those receiving the experimental vaccine formulation. The duration of the parasitemia was similar in all groups.  相似文献   

18.
The objective of this study was to compare the immune response to Neospora caninum in naturally infected heifers and heifers inoculated with a killed whole N. caninum tachyzoite preparation during the second trimester of gestation. Nine Holstein heifers were used in this study; three naturally infected heifers were born from seropositive dams, and six seronegative heifers were born from seronegative dams. Four seronegative heifers were subcutaneously vaccinated with a killed whole N. caninum tachyzoite preparation at weeks 13, 15 and 17 of gestation. A killed whole N. caninum tachyzoite preparation containing 45 mg of protein/5 ml dose was formulated with 70% of mineral oil adjuvant (13% consisting of Arlacel C, 85% Marcol 52 and 2% Tween-80). Similarly, two seronegative heifers (negative controls) were inoculated with mock-infected bovine monocytes in oil adjuvant. Humoral immune responses were tested by using an indirect fluorescent antibody test (IFAT) and an indirect enzyme-linked immunosorbent assay (ELISA) for detecting isotype specific antibodies. Cellular immune responses were assessed by lymphocyte proliferation test (LPT) and IFN-gamma production. N. caninum-specific antibody responses increased in immunized cattle by week 15 of gestation (mean reciprocal antibody titers 450+/-252), peaked at week 23 (mean 16,000+/-6400). Maximum antibody response in naturally infected heifers was observed at week 19 of gestation (mean: 3467+/-2810). Mean serum IFAT titers were significantly higher in immunized heifers compared with those in naturally infected heifers from weeks 17 to 25 (P < 0.05). Analysis of isotype specific antibodies in naturally infected heifers revealed a predominant IgG1 response in one heifer and a predominant IgG2 response in the other two. Similar titers of IgG1 and IgG2 occurred in immunized heifers. Control heifers remained seronegative throughout the study by IFAT and ELISA. Significant antigen-specific proliferation responses were only detected in naturally infected heifers in week 19 of gestation. Peripheral mononuclear blood cells (PMBC) from immunized animals produced IFN-gamma in similar concentrations to those of infected animals (P > 0.05). No abortion was seen in any experimental group; however, one calf from a vaccinated heifer died due to dystocia. All calves from vaccinated and control heifers were seronegative by IFAT at 6 months of age; in contrast, calves born from naturally infected heifers remained seropositive with titers > or = 200. Killed vaccine induced similar immune responses to those found in chronically, naturally infected cattle which did not abort; however, different immune pathways may be followed in vaccinated and natural infected heifers with differences in degree of protective immunity.  相似文献   

19.
  相似文献   

20.
Purified enzymes of Hypoderma lineatum (Insecta, Oestridae), were assayed for their proteolytic activity on bovine C3 in normal cattle sera. The products of cleavage by these serine proteases (hypodermins A, B, and C), were analysed by electrophoresis in SDS polyacrylamide gels followed by immunoblotting. The enzymatic attack was initially directed at the alpha polypeptide chain by hypodermin A at a concentration of 1 μg/ml of serum and by hypodermin B at 5 μg/ml. The generated peptides differed in their molecular size from those produced during natural degradation of C3 in a control serum by physiologically relevant enzymes. Hypodermin A, at a concentration of 1 μg/ml, also caused a cleavage of the β chain. At 5 μg/ml, hypodermin A induced total degradation of the C3 molecule. Hypodermin B (5 μg/ml) starts splitting C3 near cleavage sites of factor I. Bovine C3 appears to be highly sensitive to hypodermins A and B in normal sera. Apparent molecular sizes and alignment of the bovine C3 cleavage products are presented schematically. Hypodermin C, a collagenolytic enzyme, had no effect on C3 in normal sera. The biological consequences for the immunopathological reactions associated with hypodermosis are discussed.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号