Vaccination of calves against Ostertagia ostertagi with cysteine proteinase enriched protein fractions

Cysteine proteinase enriched fractions obtained by thiol-sepharose chromatography of Ostertagia ostertagi membrane-bound protein extract (S3-thiol) or total adult excretory-secretory (ES-thiol) products were tested in a vaccination experiment to evaluate their protective efficacy against O. ostertagi in cattle. Calves were vaccinated three times and subsequently challenged with a trickled infection of 25,000 infective larvae in total over 25 days (1000 L3/day, 5 days/week). Geometric mean cumulative egg counts in the ES-thiol group were reduced by 60% during the 2-month period between the first challenge infection and necropsy, compared to the control group (P < 0.002). No reduction in egg output was observed in the S3-thiol group. At necropsy, calves immunized with ES-thiol had a significantly higher percentage of inhibited L4 larvae (9.8%) and had in total 18% less worms than the control calves, but this reduction was not statistically significant. Both the female and male adult worms were significantly smaller in the ES-thiol group than in the control group. Although no significant difference was observed in the number of eggs per female worm between the groups, there was a trend to less eggs per female worm in the ES-thiol group. Number of worms, size of adult worms and number of eggs per female worm were not significantly different between the S3-thiol group and the control group. Systemic immunization with QuilA as adjuvant induced a significant rise in Ostertagia-specific antibody levels in the abomasal mucosa. Ostertagia-specific local antibody levels showed a significant negative correlation with the size of the adult worms, the number of eggs per female worm and the cumulative faecal egg counts. However, these correlations were quite weak and did not appear to be isotype-specific.     

Protective immunity induced by vaccination with two Haemonchus contortus excretory secretory proteins in sheep

Two excretory secretory (ES) antigens of adult Haemonchus contortus with molecular weights of 15 and 24 kDa, respectively, were evaluated as protective immunogen against haemonchosis. Sheep were vaccinated three times and subsequently challenged with 20 000 infective larvae. Vaccination induced significant reduction (>70%) in mean faecal egg counts and abomasal worm burden compared to the non-vaccinated control group or adjuvant control group. Vaccination induced ES-specific antibodies and stimulated infiltration of mast cells in the abomasal tissue.     

Vaccine testing of a recombinant activation-associated secreted protein (ASP1) from Ostertagia ostertagi

Previous vaccination trials against the economically important cattle parasite Ostertagia ostertagi have indicated the protective capacity of activation-associated secreted proteins (ASPs). The further development of these antigens into a commercial vaccine will require their recombinant expression. The aim of the current study was to clone and express Oo-asp1 in a baculovirus expression system and to evaluate the protective capacity of the recombinant protein against an O. ostertagi challenge infection in cattle. The full coding sequence of Oo-asp1 was cloned in a baculovirus expression vector in frame with a carboxy-terminal Histidine tag and recombinant virus was used to infect an insect cell culture. Western blot analysis with anti-His and anti-Oo-ASP1 antibodies showed the production of recombinant Oo-ASP1. The cell pellet containing the recombinant was subsequently used to immunize seven calves three times intramuscularly with QuilA as adjuvant. Control animals were solely injected with the QuilA adjuvant. The challenge infection with O. ostertagi consisted of 30,000 L3 larvae per animal given over 30 days (1000 larvae/day, 5 days/week) and started the same day as the final immunization. Immunization with the recombinant Oo-ASP1 did not result in any level of protection against the challenge infection. There was no reduction in faecal egg output or in worm burdens. Moreover, Western blot analyses and ELISA indicated that, although the animals raised an antibody response against the recombinant Oo-ASP1, there was hardly a response against the native Oo-ASP1, suggesting that the baculovirus expressed recombinant was wrongly folded or lacked essential secondary modifications. Further analysis of the structure of the native ASPs and their glycosylations is being done.     

Evaluation of immunization with gut membrane glycoproteins of Ostertagia ostertagi against homologous challenge in calves and against Haemonchus contortus in sheep

Peanut and ConA lectins were used as ligands to isolate glycoproteins from detergent extracts of adult Ostertagia ostertagi membranes. As judged by their profiles following SDS-PAGE, these fractions closely resembled the equivalents from Haemonchus contortus which are derived from the nematode intestinal cell microvillar membranes and which are highly protective when used as antigens. Groups of calves were immunized with the peanut and ConA binding fractions of Ostertagia, either as separate or pooled antigens mixed with QuilA as adjuvant. All calves, including controls immunized with adjuvant only, were challenged with a single dose of infective Ostertagia larvae and faecal egg counts were monitored for 5 weeks. In two experiments where the antigen fractions were pooled, moderate (30-50%), but statistically significant reductions in egg output were observed, but the number of worms was not diminished. No significant protection was observed in a third trial where groups of calves were immunized with peanut or ConA binding proteins given separately. Two further trials were conducted in sheep immunized with the same Ostertagia fractions but challenged with Haemonchus. Irrespective of whether they were administered separately or together, the Ostertagia antigens cross protected efficiently against Haemonchus reducing egg counts by between 81% and 97% and worm numbers by between 57% and 84%.     

Protection of calves against Haemonchus placei and Haemonchus contortus after immunization with gut membrane proteins from H. contortus

A vaccine containing integral membrane glycoproteins from the intestine of Haemonchus contortus was evaluated in four groups of nine worm-free calves challenged with either 8000 H. contortus or Haemonchus placei infective larvae. Vaccinates received 50 μg of the antigen and 1 mg QuilA adjuvant three times 21 days apart, while the controls got adjuvant alone. The calves were challenged 7 days after the last immunization and killed for worm counts 43 days later. Immunization resulted in high titre antibodies against the vaccine antigens and significant reduction in egg output and worm numbers of both challenge species, compared with control calves. It was concluded that vaccination of calves with native parasite gut membrane glycoproteins obtained from H. contortus conferred protection against both H. placei and H. contortus.     

日本血吸虫多价分子疫苗的保护性免疫力研究

本实验将从日本血吸虫成虫分离纯化出的２８ｋＤａ、３１／３２ｋＤａ及９７ｋＤａ蛋白混合组成多价分子疫苗免疫小鼠,再行攻击感染,观察其保护性免疫力。结果：疫苗加佐剂组成虫减虫率、肝组织减卵率及肠壁组织减卵率分别为５０．３％、７２．０％和８１．５％,均显著高于对照组（Ｐ＜０．０１）;实验组肝虫卵肉芽肿较对照组炎症反应程度轻,虫卵肉芽肿周长及面积均低于对照组（Ｐ＜０．０１）。结果提示,由日本血吸虫成虫２８ｋＤａ、３１／３２ｋＤａ及９７ｋＤａ蛋白联合组成的多价分子疫苗,具有较高的减虫率、减卵率及抑制虫卵肉芽肿形成的作用,有一定的应用前景     

Attempts to immunize sheep against Teladorsagia circumcincta using fourth-stage larval extracts

A ConcanavilinA (ConA)-binding fraction of a detergent-soluble membrane extract from Teladorsagia circumcincta (formerly Ostertagia circumcincta) fourth-stage larvae was isolated, and two vaccine trials were conducted with this preparation in groups of 7 worm-free sheep. All groups were challenged with a total of 5000 T. circumcincta larvae from 1 week after the final immunization and protection assessed by comparing the egg and worm counts, and length of developing worms, of the immunized groups with their respective controls. Immunization with the ConA-binding antigen induced high-titre serum antibody responses in both trials. However, no significant reduction in either egg count or worm burdens was observed in the vaccinated groups in either trial. It was concluded that detergent-soluble, ConA-binding extracts prepared from T. circumcincta fourth-stage larvae did not contain significantly protective antigens, despite the fact that an extract prepared in a similar manner from Ostertagia ostertagi had previously significantly protected calves against homologous challenge.     

Regulation of egg production, worm burden, worm length and worm fecundity by host responses in sheep infected with Ostertagia circumcincta

Following infection with Ostertagia circumcincta there was considerable variation in worm burdens, worm size and number of inhibited larvae even among sheep matched for age, sex, breed, farm of origin and history of parasite exposure. There was also substantial variation among sheep in the concentration of mast cells, globule leucocytes, eosinophils, IgA-positive plasma cells and parasite-specific IgA in the abomasal mucosa. With the exception of faecal egg counts over time, the parasitological and immunological traits were all continually distributed among animals and sheep did not fall into discrete high and low-responder categories. The responses were correlated. Sheep with more mast cells also had more globule leucocytes, more eosinophils, more IgA plasma cells and greater amounts of parasite-specific IgA in the abomasal mucosa. Female worm length was strongly and positively correlated with the number of eggs in utero. Faecal egg counts were associated with variation in worm number and with variation in the number of eggs in utero. The worm burden was negatively correlated with the number of globule leucocytes in the abomasal mucosa, suggesting that worm numbers are regulated by immediate hypersensitivity reactions. Decreased female worm length was associated with an increased local IgA response to fourth stage larvae. The number of inhibited larvae was positively associated with the size of the local IgA response and positively associated with the size of the worm burden. The results suggest that variation among mature sheep in faecal egg counts is due, at least in part, to variation in local IgA responses which regulate worm fecundity and to variation in local immediate hypersensitivity reactions which regulate worm burdens.     

日本血吸虫肌钙蛋白T(SjTnT)基因克隆 表达及免疫保护效果评估

目的 目的 克隆、 表达日本血吸虫肌钙蛋白T （SjTnT） 编码cDNA, 评估重组抗原抗血吸虫感染的免疫保护效果。方 方 法 法 利用PCR技术扩增SjTnT基因, 构建重组表达质粒pET28a （+） ?SjTnT并诱导表达, 用重组蛋白rSjTnT免疫BALB/c小 鼠制备免疫血清。利用免疫印迹试验 （Western blotting） 和酶联免疫吸附试验 （ELISA） 检测rSjTnT诱导的免疫反应。采 用rSjTnT免疫小鼠, 评估其诱导的免疫保护效果。结果 结果 成功克隆、 表达了日本血吸虫SjTnT基因。Western blotting显 示rSjTnT能被该重组蛋白免疫小鼠血清识别, 具有良好的免疫原性。rSjTnT能诱导小鼠产生高水平的特异性IgG抗体。 动物免疫保护试验表明, rSjTnT能诱导小鼠产生33.89%的减虫率以及43.94%的肝脏减卵率。结论 结论 制备的rSjTnT在小 鼠体内能诱导产生部分抗血吸虫感染的免疫保护效果, 为评估SjTnT的生物学功能奠定了基础。     

Immunization against sheep scab: preliminary identification of fractions of Psoroptes ovis which confer protective effects

In an attempt to enrich for potentially protective Psoroptes ovis antigens, three separate vaccine trials were conducted in which groups of sheep were immunized three times with various fractions of a soluble extract of P. ovis mites using QuilA as adjuvant. These groups, as well as controls that received adjuvant only, were challenged with P. ovis, and protective immunity was assessed by measuring lesion areas and conducting mite counts 4 and 6 weeks later. All fractions stimulated high titre serum antibodies. Most conferred some protection on sheep with active disease, although there was considerable variation between sheep in all groups, including the controls. Some fractions were more protective than the extract itself, suggesting that the protective components had been concentrated. Indeed the best fraction, obtained by ion exchange chromatography, followed by a gel filtration step, slowed lesion growth to less than a third by 6 weeks after challenge and reduced mite numbers by more than 13 times compared to control sheep vaccinated with QuilA only. However, as judged by polyacrylamide gels, the polypeptide profile of this fraction was still complex, indicating that further work is required to identify the protective components.     

Suppression of Schistosoma bovis egg production in cattle by vaccination with either glutathione S-transferase or keyhole limpet haemocyanin

Two of the antigens which have shown vaccine potential in animal experiments against Schistosoma mansoni are glutathione-S-transferase (GST) and GP38, protective epitopes of which are shared with keyhole limpet haemocyanin (KLH). We therefore tested S. bovis GST and KLH for vaccine efficacy against S. bovis in the natural Zebu cattle host. In a preliminary experiment three vaccinations with a total of 1.39 mg of native GSTs of S. bovis induced specific antibody at the time of challenge as detected by Western blotting and ELISA and mean faecal egg counts between weeks 6-10 post-challenge were reduced by 56.4 to 82.5% compared to non-vaccinated controls. Mean adult worm recoveries and tissue egg densities in large intestine and liver samples were also reduced in the vaccinated group, but these differences were not statistically significant. In a subsequent experiment one group of calves was vaccinated with a similar schedule to that used above; a second group of calves was given only two injections of GST (total 0.48 mg protein); a third group of calves was vaccinated twice with a total of 2.0 mg KLH in PBS. All three vaccination schedules induced specific antibody. Both GST vaccination schedules induced significant reductions in faecal egg counts compared to non-vaccinated controls and in this experiment tissue egg densities were also significantly reduced. A striking finding, however, was that adult worm counts were not reduced by vaccination. An essentially similar outcome resulted from KLH vaccination, since there were significant reductions in faecal and tissue egg counts in the absence of a reduction in adult worm numbers. This type of immunity mimics that induced by natural or experimental infections in the calf and clearly has implications for vaccine design.     

佐剂对日本血吸虫31/32kDa蛋白保护性免疫力的影响

本实验用纯化的日本血吸虫３１／３２ｋ Ｄａ 蛋白（ Ｓｊ３１／３２ 蛋白）辅以ｐｏｌｙａｌｐｈａｏｌｅｆｉｎ（ Ｐ Ａ Ｏ）佐剂免疫小鼠,同时比较了 Ｓｊ３１／３２ 蛋白辅以福氏完全佐剂（ Ｆ Ｃ Ａ）对小鼠保护性免疫力的影响。 Ｓｊ３１／３２ 蛋白＋ Ｐ Ａ Ｏ 组小鼠减虫率为３７５５％ ,肝减卵率为６７０２％ ; Ｓｊ３１／３２ 蛋白组小鼠减虫率为２１１８％ , 肝减卵率为 ４９０３％ ; Ｓｊ３１／３２ 蛋白＋ Ｆ Ｃ Ａ 组小鼠减虫率为 ２４０２％ , 肝减卵率为５２２４％ 。结果提示, Ｓｊ３１／３２ 蛋白辅以 Ｐ Ａ Ｏ 佐剂的减虫作用优于 Ｓｊ３１／３２ 辅以 Ｆ Ｃ Ａ 的减虫作用（ Ｐ＜ ００５）,且明显强于单纯 Ｓｊ３１／３２ｋ Ｄａ 蛋白的保护性免疫作用（ Ｐ＜ ００１）。     

Observations on cattle schistosomiasis in the Sudan, a study in comparative medicine. VI. Demonstration of resistance to Schistosoma bovis challenge after a single exposure to normal cercariae or to transplanted adult worms

Calves were immunized with Schistosoma bovis by a single experimental exposure to 10,000 normal cercariae. Some of these calves were perfused 14 weeks later, and a part of their worm loads was surgically transplanted into groups of normal recipient calves: "WPR" group calves received 500 pairs of worms; "MR" group calves received between 650 and 1,000 male worms alone. All three groups were subsequently challenged 10 weeks after surgery with 20,000 cercariae, as were a previously unexposed group of controls ("CC"). Mean post-challenge fecal egg counts in the animals immunized with cercariae ("PC" group) rose to a maximum of only 60 eggs per gram (e.p.g.), compared to 376 e.p.g. in the CC, and maximum fecal egg counts in the WPR and MR groups were also somewhat lower than in the CC, at 152 and 250 e.p.g., respectively. In spite of the much lower fecal egg counts in the PC than in the CC group, calculated adult "challenge" worm recoveries were only reduced by 11%, but PC group tissue egg densities derived from the challenge were 78-100% lower than in the CC. The WPR and MR groups had 43% and 37%, respectively, fewer worms than the CC, and mean tissue egg densities were lower by 39-63% and 63-76%, respectively, though in most cases there were no statistically significant differences from the CC.(ABSTRACT TRUNCATED AT 250 WORDS)     

旋毛虫机蚴抗原诱导小鼠抗日本血吸虫保护性免疫的研究

目的：探讨旋毛虫幼虫抗原免疫小鼠对日本血吸虫攻击感染的交叉保护作用。方法：用4种不同的旋毛虫幼虫抗原制剂经颈部皮下多点免疫小鼠，然后用日本血吸虫尾蚴30条或100条攻击感染，攻击后45d剖杀小鼠，收集成虫、肝组织和粪便中的虫卵，并计数。结果：4种不同制剂均可诱导不同程度的保护性免疫效应，以旋毛虫幼虫匀浆上清可溶性抗原（TsSA）效果较好，减虫率为21．3％，加用福氏佐剂时，其减虫率为29．3％，肝组织和粪便中的虫卵减少率分别达48％和58．5％，平均每鼠肝组织和粪便中的虫卵EPG减少率分别为41．7％和48．9％；当抗原剂量为10000条旋毛虫并加用福氏佐剂时，其减虫率达39．6％。结论：旋毛虫抗原免疫小鼠能诱导抗日本血吸虫攻击感染的免疫效应。     

重组日本血吸虫四跨膜蛋白第二亲水基团对小鼠免疫保护作用的研究

目的探讨重组日本血吸虫四跨膜蛋白第二亲水基团融合蛋白（GST-TSP2HD）抗血吸虫感染免疫保护效果。方法采用Glutathione sepharose 4B胶亲和层析法大量制备GST-TSP2HD蛋白。实验组以GST-TSP2HD融合蛋白的福氏佐剂抗原免疫C57BL/6J小鼠,同时设置佐剂对照组及GST蛋白免疫对照组,每2周加强免疫1次。加强免疫2次后每只小鼠经腹部皮肤感染（45±2）条血吸虫尾蚴。感染42 d后剖杀小鼠,经生理盐水静脉灌注收集成虫,计数减虫率,用KOH溶液消化肝组织收集虫卵,计算减卵率。组织切片观察小鼠肝组织病理变化,通过酶联免疫吸附试验检测小鼠血清中的抗体水平。结果与佐剂对照组相比,GST-TSP2HD融合蛋白免疫组的减虫率为27.10%,减卵率为32.30%;与GST蛋白免疫组相比,GST-TSP2HD融合蛋白免疫组可获得39.57%的减虫率,43.53%的减卵率。GST-TSP2HD融合蛋白免疫组肝组织中的虫卵肉芽肿数量明显减少,单个虫卵肉芽肿平均直径比佐剂对照组、GST蛋白免疫组分别下降了27.08%（P〈0.05）和40.53%（P〈0.01）,差异均有统计学意义。GST-TSP2HD能诱导高水平抗TSP2HD蛋白的特异性抗体IgG,其中IgG1、IgG2b和IgG2c亚类可能在小鼠抗血吸虫感染保护性免疫中发挥重要作用。结论日本血吸虫四跨膜蛋白是一个有效的日本血吸虫病疫苗候选分子。     

日本血吸虫重组抗原rSjGST-32诱导小鼠保护性免疫效果的比较

目的　探索日本血吸虫重组抗原rSjGST-32适合的免疫剂量。　方法　以50、100、200μg3个不同剂量rSjGST-32加佐剂皂角甙A(QuilA)50μg免疫BALB/c小鼠,同时设QuilA和PBS对照组。ELISA法检测抗体水平。末次免疫4wk后攻击感染,用减虫率及减卵率表示保护力。　结果　与PBS对照组比较,50、100、200μgrSjGST-32组的减虫率分别为38.1%,47.8%和48.8%;每克肝卵(LEPG)减少率分别为39.1%,53.5%和53.6%;每条雌虫每克肝所含虫卵数(LEPF)减少率分别为22.5%,22.8%和21.8%;抗体滴度分别达1∶51200,1∶102400和1∶102400。　结论　重组抗原rSjGST-32加QuilA佐剂免疫小鼠,以100μgrSjGST-32剂量较为适合。     

Vaccination of goats with recombinant galectin antigen induces partial protection against Haemonchus contortus infection

The efficacy of vaccination against Haemonchus contortus infection with two recombinant proteins, rHco-gal-m and rHco-gal-f, was studied in 9-10-month-old goats. Vaccination with 100 microg protein reduced faecal egg output and worm burdens by 37.25% and 41.1%, respectively. Corresponding reductions with 200 microg protein were 48.03% and 46.19%. Vaccinated groups had significantly higher IgG levels than the negative and positive controls. Significant negative correlations were detected between IgG level, mucosal homogenate IgA concentration, haemoglobin and abomasal worm burden at necropsy. By contrast a positive correlation was found between the percentage of B cells, monocytes and abomasal worm burden. These findings suggested that vaccination with a combination of recombinant rHco-gal-m/f proteins had a role in protecting goats against H. contortus infection.     

重组日本血吸虫超氧化物歧化酶融合蛋白对小鼠免疫保护作用的研究

目的 探讨重组日本血吸虫胞浆内超氧化物歧化酶（SOD）融合蛋白在抗血吸虫感染中的免疫保护作用。方法采用亲和层析方法制备纯化表达的重组SOD融合蛋白。用重组SOD融合蛋白加福氏佐剂,免疫C57BL／6J小鼠,4周后用（45±2）条日本血吸虫尾蚴攻击感染,45d后剖杀小鼠,计算减虫率和减卵率,组织切片观察小鼠肝脏的病理变化。结果实验组减虫率为35．63％,减卵率为31．17％。实验组小鼠肝脏虫卵肉芽肿数比对照组少,单个肉芽肿的平均直径比对照组小22．32％,血清抗SOD融合蛋白特异性抗体亚类IgG1、IgG2a、IgG2b水平明显高于对照组（P均〈0．05）。结论重组SOD分子能诱导一定水平的抗日本血吸虫感染免疫保护作用。     

日本血吸虫重组硫氧还蛋白小鼠保护性免疫研究

目的 观察日本血吸虫（大陆株）硫氧还蛋白重组抗原在小鼠诱导抗血吸虫感染的免疫保护作用。 方法 30只雌性C57BL/6小鼠随机分为3组，reSjcTrx免疫组：reSjcTrx（15mg/鼠）和ISA720佐剂乳化后采用小鼠相背部多点皮下注射，共免疫3次，间隔2周；ISA720佐剂对照组：小鼠仅注射ISA720佐剂和生理盐水；感染对照组不作任何处理。于末次免疫后3周，各组小鼠经腹部皮肤感染（30±1）条日本血吸虫尾蚴，感染后6周剖杀，门静脉灌注法收集成虫，计成虫数和每克肝组织虫卵数。在免疫前、攻击感染前和小鼠剖杀前分别采血并分离血清，用ELISA检测重组抗原特异性IgG抗体。并对reSjcTrx 进行十二烷基磺酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）和蛋白质印迹（Western blotting）分析。 结果 ELISA检测表明，reSjcTrx免疫组小鼠产生特异性IgG抗体应答，并诱导小鼠产生对攻击感染的减虫率和肝组织减卵率分别为22.8%和29.5%，与ISA720佐剂对照组和感染对照组相比，差异均有统计学意义（P﹤0.05）。SDS-PAGE和Western blotting的结果表明，该重组抗原相对分子质量（Mr）约14 000（含载体的6个氨基酸），可被日本血吸虫感染兔血清和reSjcTrx免疫小鼠血清所识别。 结论 reSjcTrx免疫小鼠可产生一定的抗血吸虫感染的保护作用。