Efficacy of vaccination in preventing giardiasis in calves

The objective of this study was to evaluate the efficacy of a vaccine in the prevention of Giardia duodenalis infection in calves. Six 2-week old calves were vaccinated subcutaneously with a sonicated G. duodenalis trophozoite vaccine. Six 2-week old control calves received a subcutaneous injection of sterile phosphate-buffered-saline mixed with adjuvant. Injections were repeated after 28 days. Eleven days after the second injection, calves were challenged orally with 1x10(5) purified G. duodenalis cysts from a naturally infected calf. Throughout the study, fecal samples were collected at regular intervals and examined for the presence of G. duodenalis cysts. Blood samples were collected weekly until G. duodenalis challenge and bi-weekly following challenge. Calves were euthanized 14 days after challenge and G. duodenalis trophozoites within the small intestines were enumerated. Serum antibody titers were significantly higher in vaccinated compared to non-vaccinated calves. Vaccinated calves tended to excrete more G. duodenalis cysts in their feces than non-vaccinated calves. The number of trophozoites in the small intestine was not different between vaccinated and non-vaccinated calves. Changes consistent of moderate enteritis were found in the intestines of one vaccinated and one non-vaccinated calf. Despite a serological immune response following vaccination, this vaccine was not efficacious in preventing giardiasis or reducing cyst shedding in calves.     

Efficacy of vaccination with porcine reproductive and respiratory syndrome virus following challenges with field isolates in Japan

The objective of this study was to evaluate the influences of genetic and antigenic variations in field isolates of porcine reproductive and respiratory syndrome virus (PRRSV) on vaccine efficacy. Four-week-old pigs were vaccinated with a commercial modified live virus vaccine. Four weeks after vaccination, pigs in both the vaccinated group and the non-vaccinated group were challenged intranasally with 10(7) TCID(50) of PRRSV wt-11 (Experiment 1) or PRRSV wt-7 (Experiment 2). Based on genome sequencing of ORF5 and cross neutralization test results, PRRSV wt-11 is similar to the vaccine strain, whereas wt-7 is distinct from the vaccine strain. In the vaccinated challenged groups, clinical signs were less severe, the mean rate of weight gain was greater, and gross lung lesions were less severe when compared with the non-vaccinated challenged groups in both experiments. In Experiment 1, the virus was isolated from serum at 3 days post-challenge, and the mean virus titers in broncho-alveolar lavage fluids (BALF) and tissues were lower in pigs in the vaccinated challenged groups compared with those in the non-vaccinated challenged group. In Experiment 2, virus isolation from serum, BALF and tissues showed no significant differences between the groups. These results suggest that commercial PRRSV vaccine could be effective in reducing clinical disease following a challenge with field isolates of PRRSV. However, with regards to virological protection, the efficacy of the vaccine may be affected by the nature of the PRRSV isolates.     

The effectiveness of vaccinating gilts against parvoviruses in a herd with endemic parvovirus infection

An inactivated vaccine against swine parvovirosis with a lipoid adjuvant was tested in a herd infested with parvoviruses. The titre of the haemagglutination-inhibition antibodies was studied at the time of the first pregnancy in two groups of gilts included in the herd at the age of 7.5 months - one group vaccinated, the other left untreated. In the vaccinated group the geometrical means of the titres were significantly higher than in the non-vaccinated group throughout the time of study. The difference in the average number of piglets per litter between the two groups was evaluated after parturition. On an average, the gilts of the vaccinated group had 1.5 more live pigs per litter (P less than 0.05). As also found, when the antibody titre increases by log 10, the number of piglets per litter increases by 1.55. On the basis of the results the vaccination of gilts against swine parvovirosis in endemically infested herds is considered an efficient preventive measure having a high economic effect.     

Program of vaccination and antibiotic treatment to control polyserositis caused by Haemophilus parasuis under field conditions

The present study investigated the effects of vaccinating sows and piglets or piglets alone against Haemophilus parasuis on the prevalence of H. parasuis in nasal swabs, on the humoral and cellular immune responses, and on the production parameters of piglets at 3 Korean farms with a clinical history of polyserositis caused by H. parasuis. Piglets born to vaccinated or non-vaccinated sows were subdivided into 3 groups: vaccinated sows and vaccinated pigs (VS-VP), non-vaccinated sows and vaccinated pigs (NVS-VP), and non-vaccinated sows and non-vaccinated pigs (NVS-NVP). The proportion of piglets with positive nasal swabs was significantly lower (P < 0.05) in the vaccinated animals (VS-VP and NVS-VP groups) than in the non-vaccinated animals (NVS-NVP group) at 35 and 60 d of age at the 3 farms. The overall growth performance (from 7 to 60 d of age) of the vaccinated piglets was significantly better (P < 0.05) than that of the non-vaccinated piglets at the 3 farms. Piglets in the VS-VP group had significantly higher levels (P < 0.05) of H. parasuis-specific IgG antibodies, lymphocyte proliferation, and interferon-γ-secreting cells than piglets in the NVS-VP and NVS-NVP groups on days 1, 7, 21, 35, and 60 after birth at the 3 farms.     

Anaplasma marginale inactivated vaccine: dose titration against a homologous challenge

The present study was performed to dose-titrate an Anaplasma marginale experimental immunogen derived from partially purified initial bodies from three geographically different Mexican strains. Three five-bovine groups were inoculated twice on days zero and 21 with A. marginale initial bodies equivalent to 1.5×10¹⁰ (group I), 3×10¹⁰ (group II) or 6×10¹⁰ (group III) infected erythrocytes mixed with STDCM® adjuvant. A similar group served as non-vaccinated controls. All four groups were challenged with 1×10⁸ infected erythrocytes from a donor cow with an increasing rickettsemia of strain MEX-15 on day 87 post-vaccination. The prepatent period was very similar for all four groups. All five non-vaccinated controls presented typical acute anaplasmosis syndrome reaching a mean of 30.9% rickettsemia and a loss of 73.4% in the packed cell volume (PCV). Two of five controls died of acute anaplasmosis. Within the vaccinated groups only one animal (group II) suffered acute disease and died. Although all the other vaccinated animals were free of clinical signs, they developed very low rickettsemias (3.2, 3.8 and 4.3%) and PCV losses of 49.9, 47.8, and 49.3% for groups I, II and III. The starting mean weight was very similar for all four groups. All animals lost weight following challenge but losses for groups I and II were lower and significantly different from group IV losses (P0.1). Although there were no significant differences among vaccinated groups, group III was more severely affected. Taken altogether, these results show a 93.3% protection against both illness and death for all groups; and 100% protection for groups I and III, and 80% for group II.     

Impact of field vaccination with a Theileria annulata schizont cell culture vaccine on the epidemiology of tropical theileriosis

Tropical theileriosis, caused by Theileria annulata, is an important tick-borne disease of cattle. A cell culture attenuated vaccine has been developed in our laboratory by long-term in vitro propagation of the schizont stage of the parasite. A longitudinal study was conducted at selected farms housing indigenous, cross-bred and exotic animals to investigate the effect of vaccination on the epidemiology of the disease. A total of 120 animals in 4 age groups were vaccinated with the vaccine before the onset of disease season. An equal number of age-matched animals were kept as controls at the same sites. Animals were monitored for 14 months at monthly intervals. The 97.5% vaccinated animals showed a rise in antibody titres 1 month post-vaccination, as determined by single dilution ELISA. The 78.3% of non-vaccinated animals became sero-positive over the period of observation. Mean antibody titres were significantly higher in vaccinated than non-vaccinated animals. Cross-bred animals showed higher antibody titres followed by exotic and indigenous animals in both the vaccinated and non-vaccinated groups. However, the antibody titres in animals of different ages were similar. The 36.7% vaccinated and 64.2% non-vaccinated animals became carriers (<0.5% piroplasms in erythrocytes) during the observation period. Clinical cases of theileriosis were recorded only in the non-vaccinated group suggesting that vaccinated animals were sufficiently immune to withstand field tick challenge for at least 14 months.     

Antibody response of calves to immunoaffinity-purified bovine respiratory syncytial virus VP70 after vaccination and challenge exposure.

Immunoaffinity-purified bovine respiratory syncytial virus (BRSV) fusion (F) protein elicited anti-BRSV-specific antibody responses in BRSV-seronegative calves. After primary vaccination, all calves seroconverted to BRSV as determined by the virus neutralization (VN) test and developed anti-F protein antibodies detectable by protein immunoblot analyses. Subsequent vaccinations induced greater than twofold increase in VN titer in 3 of 9 (33%) calves, and 1 calf became VN-negative, but still had nonneutralizing antibody detectable by protein immunoblot analysis. This calf remained seronegative after challenge exposure. Two groups of calves were vaccinated IM with immunoaffinity-purified BRSV F protein. Each dose was 2 ml containing 20 micrograms of purified F protein. Freund's adjuvants were used for all vaccinations, with Freund's complete adjuvant used for the primary vaccination and Freund's incomplete adjuvant for subsequent vaccinations. The vaccine was administered to both groups at weeks 0 and 3; the first group received a third vaccination at weeks 21. Group-1 and -2 vaccinated calves and non-vaccinated contact controls were intranasally aerosol challenge-exposed with low cell culture-passage BRSV on weeks 22 and 9, respectively. Eight of 9 vaccinated calves did not develop a humoral anamnestic response following challenge exposure, as demonstrated by VN test and protein immunoblot analyses. Calf 14 from group 1 which had a 1:2 VN antibody titer prior to vaccination, was the only calf that developed an anamnestic response.(ABSTRACT TRUNCATED AT 250 WORDS)     

Prevention of bovine respiratory syncytial virus infection and clinical disease by vaccination

A double blind field trial was carried out with a live attenuated bovine respiratory syncytial virus vaccine. The trial involved 530 calves, two to 10 months old, on 27 dairy farms, where respiratory problems due to bovine respiratory syncytial virus infections had been observed during the preceding year. In 17 herds either all calves were vaccinated (nine groups) or all calves received a placebo (eight groups). In 10 herds half the number of calves were vaccinated and the other half kept as non-vaccinated controls. Calves were vaccinated intramuscularly twice with an interval of four to five weeks. These groups were under regular clinical observation and animals were tested periodically for antibodies to bovine respiratory syncytial virus and parainfluenza type 3 virus. Serological examination indicated that no bovine respiratory syncytial virus infection had occurred prior to the first vaccination in August. Vaccination did not cause adverse reactions. Low concentrations of neutralising and complement fixing antibodies were induced by vaccination and a sharp increase of antibody titres was observed after natural infection of vaccinated animals. Infections with bovine respiratory syncytial virus occurred in six out of eight non-vaccinated groups, in nine out of 10 partly vaccinated groups and in only two out of nine completely vaccinated groups. Virus infection in completely vaccinated groups was significantly reduced compared with partly vaccinated and non-vaccinated groups. The incidence of bovine respiratory syncytial virus lower respiratory disease was significantly reduced in completely vaccinated groups compared to non-vaccinated groups. Generally only mild signs of upper respiratory disease were present in completely vaccinated groups after bovine respiratory syncytial virus infection.(ABSTRACT TRUNCATED AT 250 WORDS)     

Ear necrosis reduction in pigs after vaccination against PCV2

The influence of sows vaccination against PCV2 on the prevalence of ear necrosis syndrome (ENS) reduction among weaners was analyzed using 12,931 piglets from 45 consecutive batches, born to both, vaccinated and non-vaccinated sows. The results were statistically tested with a nonparametric Kruskal-Wallis and Chi-square tests.The results show that vaccination against PCV2 significantly reduced the prevalence of ENS (p < 0.05). The percentage of affected pigs born to vaccinated sows was about over two times lower than in both groups of pigs born to non-vaccinated females (before the vaccination implementation and after its withdrawing). Even more distinct were the differences in the intensity of the lesions (p < 0.05). In the group of pigs born to vaccinated sows, the percentage of severe lesions was three times lower than in the pigs born to non-vaccinated sows.It conclusion, it could statement that vaccination against PCV2 might be effective in reduction of ENS.     

The effect of a killed porcine reproductive and respiratory syndrome virus (PRRSV) vaccine treatment on virus shedding in previously PRRSV infected pigs

Two experiments were conducted to investigate if virus shedding could be reduced following a killed porcine reproductive and respiratory syndrome virus (PRRSV) vaccination (KV) of PRRSV infected pigs. In experiment 1, PRRSV infected pigs were vaccinated with KV on days 14 and 28 following infection. Viremia and serum neutralizing (SN) antibody were compared to infected pigs with no KV. The second experiment was conducted in an identical manner. In addition to viremia and SN antibody, virus in oropharyngeal scrapings and interferon gamma (IFN-gamma) producing cells were monitored. Magnitude and duration of viremia were not different between KV vaccinated and non-vaccinated groups. No virus was detected in oropharyngeal scraping from any pig, nor was there a difference in the detection of viral RNA. In both experiments, however, increases in SN titer and number of IFN-gamma producing cells were observed. The SN titer was significantly higher in KV vaccinated groups than in non-vaccinated group on days 42 and 42-56 following infection in experiments 1 and 2, respectively. The number of IFN-gamma producing cells was slightly higher in KV vaccinated groups than in non-vaccinated group on days 42 and 63. These observations suggest that KV had no effect on virus shedding. However, previously infected pigs responded immunologically to KV, as demonstrated by increases in SN antibody titers and IFN-gamma producing cells.     

The effect of season and vaccination for Glässer's disease and post-weaning Colibacillosis in an outdoor pig unit endemically infected with virulent strain of Haemophilus Parasuis serotype 5 and pathogenic Escherichia coli

The objective of this field trial was to determine if vaccination against Haemophilus parasuis serovar 5 (HPS 5) and pathogenic serotypes of Escherichia coli would improve nursery pig performance in an outdoor unit in different seasons. The unit was concurrently infected with HPS 5 and with different serotypes of E. coli. All piglets were born to HPS 5 vaccinated sows. The trial was carried out in four (two summer and two winter) groups. Group 1 (E. coli and HPS vaccinated, summer season) (n = 362): Piglets were vaccinated pre-weaning with inactivated E. coli-VT2e-toxin and post-weaning against HPS 5. Group 2 (non-vaccinated, summer season) (n = 349): Piglets were not vaccinated. Group 3 (E. coli and HPS vaccinated, winter season) (n = 358): The animals were analogously treated as Group 1. Group 4 (non-vaccinated, winter season) (n = 353): Piglets were not vaccinated. The following parameters were evaluated: A: average daily nursery weight gain (ADG), B: nursery mortality, C: feed efficiency (FE). No significant weight differences were detected within the vaccinated and non-vaccinated summer or winter raised groups of weaners. Summer raised weaners were significantly (P<0.05) heavier from day 35 on than winter raised animals. ADG and FE of summer raised pigs were significantly better (weeks 1-3 P<0.05; fourth week post-weaning P<0.01) during the nursery period than that of the winter raised groups. Winter raised vaccinated weaners showed during the last week of nursing significantly (P<0.05) better daily gain and feed efficiency compared with the non-vaccinated winter raised animals. Non-significant ADG and FE differences were detectable between the summer raised vaccinated or non-vaccinated groups of pig. Winter raised non-vaccinated animals suffered significantly (P<0.05) higher nursery mortality (10.63%) compared to the winter raised vaccinated animals. Implication: In cases of concurrent infections with HPS 5 and with different serotypes of E. coli, especially during winter season, vaccination against both diseases is suggested.     

Vaccination as a possible means of preventing lantana poisoning

The toxic triterpene acids lantadene A and lantadene B were isolated from Lantana camara and conjugated to bovine serum albumen or haemocyanin. The conjugates were emulsified with complete Freund's adjuvant and injected into sheep and cattle. Vaccinated animals produced antibodies against the toxic compounds. Cholestasis was less severe in vaccinated than in non-vaccinated sheep challenged with a toxic dose of lantana. The results indicated a mild protective effect of vaccination against the hepatotoxic effects of lantana toxins.     

Vaccination of rabbits against coccidiosis using precocious lines of Eimeria magna and Eimeria media in Benin

Three groups of twelve 35-day-old rabbits were used for the experiment. Two groups were vaccinated with a mixture of precocious lines of Eimeria magna and Eimeria media originating from corresponding wild strains isolated in Benin. One group benefited of a booster whereas the second one was kept without booster. A third non-vaccinated group was used as control. All groups were challenged per os with an equal mixture of the wild strains of E. magna and E. media at a dose of 104 oocysts per animal. Three weeks after the challenge inoculation, no case of diarrhoea was recorded in the two groups of vaccinated rabbits, as compared to the non-vaccinated rabbits that developed diarrhoea. No mortality was recorded in the three groups. During the patent period, oocyst output of vaccinated rabbits was significantly lower than that of control animals (P < 0.01), confirming a good immunogenic characteristic of the precocious lines. No booster effect was noticed for the boost vaccinated group. The daily weigh gain of the two groups of vaccinated rabbits was significantly higher than that of the non-vaccinated rabbits (P < 0.05). Consequently the precocious lines of Benin origin turned out to be immunogenic and therefore constitute good potential candidates for vaccine production for this country.     

Changes in plasma fibrinogen levels in experimental Mycoplasma bovis arthritis in calves

Plasma fibrinogen levels were measured as a means of following the course of an intravenous and intraperitoneal challenge of vaccinated and non-vaccinated animals in an experimental Mycoplasma bovis arthritis in calves. Intraperitoneal challenge failed to induce as much elevation of fibrinogen concentration as intravenous challenge in both the vaccinated and non-vaccinated groups.The elevation of fibrinogen levels among the vaccinated calves remained within the normal range of 300–800 mg% throughout, irrespective of the route of challenge. In contrast, the level rose to over 1600 mg% ten days postchallenge in all but one of the non-vaccinated calves that were challenged intravenously. The relatively low plasma fibrinogen levels in non-vaccinated calves that were challenged intraperitoneally correlated with the absence of arthritis in this group. In general, there was an inverse correlation between high fibrinogen levels and protection from M. bovis arthritis.     

Effect of sow vaccination against Mycoplasma hyopneumoniae on sow and piglet colonization and seroconversion, and pig lung lesions at slaughter

The objectives of the present study were to compare Mycoplasma hyopneumoniae (Mh) colonization and serologic status on Mh vaccinated and non-vaccinated sows and to assess the effect of sow vaccination on colonization and serologic status of their piglets at weaning as well as presence of enzootic pneumonia (EP) lung lesions at slaughter. Fifty sows (25 vaccinated and 25 unvaccinated) as well as five of their piglets were included in the study. Blood samples and nasal swabs from sows at 7 weeks pre-farrowing and 1 week post-farrowing and from piglets at 3-4 weeks of age were taken. Nasal swabs and sera were tested by a nested polymerase chain reaction (nPCR) to detect Mh DNA and by an enzyme-linked immunosorbent assay (ELISA) test to detect antibodies to the pathogen, respectively. Finally, at 23 weeks of age, pigs were sent to the slaughter where the extension of EP-compatible gross lesions was assessed. Vaccination with two doses of Mh vaccine resulted in a significantly higher (p<0.05) percentage of seropositive sows than in the non-vaccinated group at 1 week post-farrowing. On the contrary, no statistical significant differences were found in the number of nasal nPCR positive sows among different treatments (p>0.05). At 3-4 weeks of age, a significantly higher percentage (p<0.001) of seropositive piglets came from vaccinated than from non-vaccinated sows. Although the number of Mh infected piglets coming from non-vaccinated sows was higher than the one from vaccinated sows, the difference was not statistically significant (p>0.05). Overall, piglets from vaccinated sows had a significant lower (p<0.05) mean of EP-compatible lung lesions (1.83+/-2.8) than piglets from non-vaccinated sows (3.02+/-3.6). Under the conditions described in this study, sow vaccination did not affect sow or piglet colonization but increased the percentage of seropositive sows and piglets at weaning and reduced significantly the mean EP-compatible lung lesion scoring at slaughter.     

Strain specificity of the immune response of pigs following vaccination with various strains of porcine reproductive and respiratory syndrome virus

The primary objective of the study was to determine strain specificity of the immune response of pigs following vaccination with selected strains of porcine reproductive and respiratory syndrome virus (PRRSV). The experimental design included five groups (I through V, six pigs per group) free of antibody for PRRSV at the beginning of the experiment (day 0). On day 0, groups III, IV, and V were vaccinated with attenuated versions of PRRSV strains 8, 9, and 14, respectively. On day 21, the immunity of group II (non-vaccinated/challenged controls) and groups III, IV, and V was challenged by exposing each pig to a composite of the virulent versions of these same three strains. On day 35, all pigs, including non-vaccinated/non-challenged pigs of group I, were necropsied. Lungs and selected lymph nodes were examined for lesions. Serum samples obtained at weekly intervals throughout the study and lung lavage fluids obtained at necropsy were tested for the presence of PRRSV and its strain identity. Before challenge the strain of PRRSV identified in the sera of vaccinated pigs was always that with which the particular pig had been vaccinated (i.e. homologous strain), whereas, with one exception, only heterologous strains were identified after challenge. This apparent strain exclusion as a result of vaccination was statistically significant (P = 0.004). The tendency for heterologous strains to predominate after challenge suggests that a pig's immune response to PRRSV has some degree of strain specificity. Whether this finding has any clinical relevance in regard to immunoprophylaxis remains to be determined.     

Modulary effects of temperature on antibody response and specific resistance to challenge of channel catfish, Ictalurus punctatus, immunized against Edwardsiella ictaluri

The effects of various temperature treatments on the level of the humoral antibody response in channel catfish immunized with formalin killed Edwardsiella ictaluri was determined in laboratory controlled experiments. Immunized fish that were held at 25 degrees C for 30 days and 12 degrees C for an additional 30 days had higher antibody titers, and were more protected upon challenge, than immunized fish held at 25 degrees C for 60 days. Also immunized catfish held at 25 degrees C for 5 or 10 days followed by 12 degrees C water had higher antibody titers than immunized fish held at 12 degrees C or 25 degrees C for 60 days. In a field experiment carried out during winter and spring (February-May) fingerling channel catfish were vaccinated with E. ictaluri using intraperitoneal injection or immersion with either sonicated or whole cell preparations. Following challenge, the fish vaccinated by immersion in the sonicated preparation had 11.8% mortality whereas the groups immersed in whole cell bacterin, injected with the whole cell bacterin in adjuvant, or injected with sonicate showed 24.6, 57.9 and 41.7% mortality, respectively. Although the fish vaccinated by immersion with the sonicated bacteria had lower antibody titers than those vaccinated by the other methods the immersion vaccinates were more protected against challenge with the pathogen.     

Immunity to Escherichia coli in pigs: Antibody Secretion by the Mammary Gland after Intramammary or Intramuscular Vaccination with an E. coli Vaccine

Indirect hemagglutinating antibody titres in individual gland samples of colostrum and milk from 13 sows were measured. Five of the sows were vaccinated via a mammary gland and five by the intramuscular route with a live formalinised Escherichia coli vaccine and three remained as non-vaccinated controls.

Antibody titres were higher in colostral and milk whey from the vaccinated sows than from non-vaccinated groups. The inoculated gland in the group of sows given vaccine by the intramammary route secreted milk containing markedly more antibodies to the vaccine E. coli strain than did the non-vaccinated glands. Milk from the vaccinated gland did not contain higher titres to heterologous E. coli O antigens than milk from non-vaccinated glands. Serum titres were the same or higher than the titres in colostrum from non-vaccinated glands.

     

Vaccination of cattle with Mycobacterium bovis culture filtrate proteins and CpG oligodeoxynucleotides induces protection against bovine tuberculosis

Culture filtrate protein (CFP) vaccines have been shown to be effective in small animal models for protecting against tuberculosis while immunisation with these types of vaccines in cattle has been less successful. A study was conducted in cattle to evaluate the ability of selected adjuvants and immunomodulators to stimulate protective immune responses to tuberculosis in animals vaccinated with Mycobacterium bovis CFP. Seven groups of cattle (n=5) were vaccinated with M. bovis CFP formulated with either Emulsigen or Polygen adjuvant alone or in combination with a specific oligodeoxynucleotides (ODN), polyinosinic acid: polycytidylic acid (poly I:C) or poly I:C and recombinant granulocyte-macrophage colony stimulating factor. Two additional groups were vaccinated subcutaneously with BCG or non-vaccinated. In contrast to the strong interferon-gamma (IFN-gamma) responses induced by BCG, the CFP vaccines induced strong antibody responses but weak IFN-gamma responses. The addition of CpG ODN to CFP significantly enhanced cell-mediated responses and elevated antibody responses to mycobacterial antigens. Of the CFP vaccinated groups, the strongest IFN-gamma responses to CFP vaccines were measured in animals vaccinated with CFP/Emulsigen+CpG or CFP/Polygen+CpG. The animals in these two groups, together with those in the BCG and non-vaccinated groups were challenged intratracheally with virulent M. bovis at 13 weeks after the first vaccination and protection was assessed, by examination for presence of tuberculous lesions in the lungs and lymph nodes, 13 weeks later at postmortem. While BCG gave the best overall protection against tuberculosis, significant protection was also seen in animals vaccinated with CFP/Emulsigen+CpG. These results establish an important role for CpG ODN in stimulating protective Th1 responses to tuberculosis in cattle and indicate that a sub-unit protein vaccine can protect these animals against tuberculosis.     

接种猪肺炎支原体疫苗后抗体水平变化规律的研究

为探讨免疫接种5种猪肺炎支原体疫苗后血清抗体的变化规律,选用120头健康仔猪作为实验动物,随机分成A、B、C、D、E5个试验组和1个对照组,每组20头猪。在7日龄和21日龄左右,按照各个疫苗厂商提供的最佳免疫程序,对试验组的仔猪进行免疫接种,对照组的仔猪颈部肌肉注射2.0mL生理盐水。分别于20、50、80、140日龄采血分离血清,并用ELISA方法检测血清中的猪肺炎支原体抗体水平。结果表明,不同疫苗免疫接种试验猪后抗体产生不同。20日龄时,各试验组抗体水平差异不显著(P>0.05),且抗体阳性率不高;50日龄时,抗体阳性率明显升高,A、C两组产生的抗体水平极显著高于B、D组及对照组(P<0.01),E组极显著高于D组及对照组(P<0.01),B组显著高于D组及对照组(0.01相似文献