Specificity of the indirect enzyme-linked immunosorbent assay for detection of pseudorabies virus antibodies in pigs exposed to bovine herpesvirus-1

Six 5-week-old pigs were inoculated intranasally (IN) with 10(7.6) TCID50 of bovine herpesvirus-1 (BHV-1). Three of the pigs also were inoculated IV with a similar dose of BHV-1. Clinical responses were not observed in these 6 pigs before oronasal challenge exposure with 10(7.8) TCID50 of virulent pseudorabies virus (PRV) at postinoculation day 42. Two pigs inoculated IN with BHV-1 and challenge exposed with PRV remained healthy, whereas the remaining 4 pigs developed severe clinical signs of pseudorabies and were moribund at postinoculation day 50 (8 days after challenge exposure). Anti-BHV-1 antibodies were demonstrable by ELISA in all 6 pigs and by serum neutralization (SN) in 5 pigs before challenge exposure with PRV. Anti-PRV antibody was not detected by ELISA or SN before challenge exposure to PRV. After challenge exposure to PRV, pigs with humoral antibody to BHV-1 responded anamnestically, and anti-PRV antibody activity was demonstrable by ELISA and SN in the 2 surviving pigs.     

In vivo and in vitro reactivation of latent pseudorabies virus in pigs born to vaccinated sows

Latency of pseudorabies virus (PRV) was established in 8 of 9 pigs born to 2 vaccinated sows. Pigs had high, low, or no maternal antibody titers at the time of the initial inoculation. At postinoculation months 3 to 4, latent PRV could be reactivated in vivo by the administration of large doses of corticosteroids. In most pigs, the stress-simulating treatment resulted in recrudescence of virus shedding after lag periods of 4 to 11 days. In 3 pigs, virus shedding was without clinical signs of disease, whereas clinical signs that developed in 4 pigs appeared to be due to the corticosteroid treatment, rather than to the reactivation of PRV. Pigs with a log10 neutralizing antibody titer of less than or equal to 2.55 at the onset of corticosteroid treatment had a booster response. Reactivated PRV spread to sentinel pigs housed with the inoculated pigs. Reactivation of PRV was also demonstrated in vitro. Explant cultures of trigeminal ganglia from pigs killed between postinoculation months 4 to 5 produced infectious virus. Restriction endonuclease analysis indicated that the reactivated PRV was indistinguishable from virus isolated shortly after the primary infection. Seemingly, pigs with maternal antibodies can become latently infected and therefore may be regarded as potential sources of dissemination of PRV.     

Virus isolation and immune responses in susceptible swine exposed with pseudorabies virus (Shope strain).

Eighteen seronegative swine weighing from 9 to 11 kg were exposed intranasally with the Shope strain of pseudorabies virus (PRV) and were observed for 21 days in an experiment to detect virus shedding and immune responses. All swine had PRV in their nasal passages at 7 days after exposure; they also had precipitating antibodies to PRV as determined by the microimmunodiffusion test (MIDT) and very low levels of virus-neutralizing (VN) antibodies. The PRV was isolated from only 2 swine at postexposure day 14; all swine were MIDT positive, and VN titers ranged from 4 to 128. Virus was not isolated from the swine at 21 days after exposure, but all were MIDT positive; VN titers ranged between 8 and greater than or equal to 256.     

Immunogenicity and safety of an attenuated Bordetella bronchiseptica vaccine in pigs

The immunogenicity and safety of an attenuated Bordetella bronchiseptica vaccine for swine atrophic rhinitis (AR) was evaluated in 22 hysterectomy-produced, colostrum-deprived pigs and 18 conventional pigs. None of 8 pigs inoculated at 7 days of age intranasally with greater than or equal to 3 X 10(5) colony-forming units (CFU) of vaccinal strain/pig and 2 of 5 pigs inoculated at 7 days of age intranasally with 3 X 10(4) CFU of the vaccinal strain/pig developed AR after intranasal challenge exposure with a virulent strain at postinoculation week (PIW) 3. The remaining 3 vaccinated pigs and 4 nonvaccinated pigs developed AR. Thirteen pigs were inoculated intranasally with 3 X 10(6) to 3 X 10(9) CFU of the vaccinal strain at 7 days of age. At PIW 12, the pigs were killed and necropsied. None of the pigs had clinical signs of AR and/or pneumonia. Virulence was studied by transmission of vaccinal strain through 3 serial growing passages on the nasal mucosa of a litter of hysterectomy-produced colostrum-deprived pigs. Inoculum (nasal swab samples from 2 pigs 4 days after inoculation with 10(8) CFU of vaccinal strain at 5 days of age) was inoculated into the nasal cavity of 2 nonvaccinated pigs. This procedure was repeated 3 times. After the 1st passage, the vaccinal strain was recovered on postinoculation day 4, but after postinoculation day 4, the vaccinal strain was not recovered until the end of the 3rd passage. Turbinate atrophy or pneumonia was not recognized in these inoculated pigs. The vaccinal strain provided immunogenicity without ill effects.     

Cellular immunity shown in pseudorabies virus-infected pigs by leukocyte migration-inhibition procedure.

Cellular immunity in pigs inoculated with pseudorabies virus (PRV) was studied by the agarose plate technique of direct leukocyte migration-inhibition procedure. Migration of leukocytes from PRV-infected pigs was inhibited in the presence of PRV antigen, whereas migration of leukocytes from nonexposed pigs was not inhibited in the presence of the same antigen. The migration of leukocytes collected 4 days after intranasal exposure to PRV was inhibited; humoral antibodies could not be detected until 7 days after exposure. Cellular immunity was present in pigs 14 days after inoculation with inactivated PRV antigens; low concentrations of neutralizing and precipitating antibodies were present at this time. The leukocyte migration-inhibiton procedure was found to be a useful tool in studying the role of cellular immunity in PRV infections.     

伪狂犬病弱毒株的分离鉴定及生物学特性的研究

在流行病学调查中分离到1株病毒,经鉴定为伪狂犬病弱毒株,定名为F971株。分离病毒经克隆纯化后测得其毒价为10^7.59TCID50/ml,通过细胞中和试验表明分离病毒能也有效地被猪伪狂犬病毒闽A株阳性血清中和。病毒在电镜下可以清楚地观察到囊膜及外周纤突。分离株对3日龄乳鼠有一定的致病力,但对家兔、3日龄乳猪及妊娠母猪都有很高的安全性。用不同的剂量10^0、10^-1、10^-2肌肉注射3日龄乳猪后14天用10^5.7TCID50伪狂犬病强毒攻击,所有试验仔猪均得到保护。用分离株免疫母猪,其后代可获高滴度的母源抗体,15日龄的仔猪能抵御10^5.7TCID50强毒的攻击。用ELISA普查试剂盒测定免疫猪抗体,结果均为阳性,而用g^1-ELISA试剂盒测定抗体时,结果均为阴性。证明分离株具有缺损g^1糖蛋白的特性。综合上述特性,确定F971为1株g^1糖蛋白缺损的猪伪狂犬病弱毒株。     

伪狂犬病病毒弱毒株LY株的分离鉴定

从辽阳某猪场的10日龄仔猪中分离到1株病毒,经纯化后测得其毒价为107.29TCID50/mL.细胞中和试验表明,该病毒能被猪伪狂犬病病毒标准阳性血清所中和.电镜下可见到典型的疱疹病毒粒子,具有囊膜及外周纤突.所分离的病毒对氯仿、胰蛋白酶、乙醚敏感,在pH5.0～9.0下稳定,56℃ 30 min可以灭活.应用特异性引物,通过PCR能扩增出伪狂犬病病毒1 240 bp的gD基因.分离病毒对3日龄乳鼠有一定的致病力,但对家兔、3～5日龄仔猪及妊娠母猪都有很高的安全性.用不同剂量的病毒培养液肌肉注射于3～5日龄仔猪,14 d后用105.7TCID50伪狂犬病病毒强毒攻击,所有试验仔猪均可得到有效保护.用分离毒免疫母猪,其后代可获高滴度的母源抗体,15日龄的仔猪能抵抗105.7TCID50强毒的攻击.试验的结果初步说明,所分离的病毒为伪狂犬病病毒(命名为PRV LY株),并可能是一株弱毒株,而且具有很好的免疫保护作用.     

Vaccination of newborn pigs with an attenuated strain of transmissible gastroenteritis virus.

Clinical signs of transmissible gastroenteritis were not observed in newborn pigs orally inoculated with the high-passaged vaccinal transmissible gastroenteritis virus (TO-163 strain). Vaccinal viral multiplication in digestive tract of newborn pigs fed colostrum before inoculation and kept at 21 to 22 C was diminished, but was not diminished in those fed colostrum and kept at 10 to 11 C. Other groups of newborn pigs inoculated with the attenuated vaccinal virus and kept at 18 to 22 C or at 31 to 34 C were challenge exposed with virulent intestinal virus on the 1st, 2nd, . . ., or 6th postinoculation (PI) days. In the groups kept at 18 to 22 C, 2 of 7 inoculated pigs challenge exposed with virulent virus on the 3rd PI day, 4 of 7 pigs exposed on the 4th PI day, and all of the pigs exposed on and after the 5th PI day survived the exposure. In the groups kept at 18 to 22 C, the attenuated vaccinal virus was distributed mainly in the respiratory organs and lymphatic tissues. On the contrary, in the groups kept at 31 to 34 C, all of the pigs died in 2 to 5 days after challenge exposure, and the attenuated vaccinal virus was scarcely detected in any of the pigs.     

Attenuated properties of thymidine kinase-negative deletion mutant of pseudorabies virus

A thymidine kinase (TK)-negative (TK-) deletion mutant of the Bucharest (BUK) strain of pseudorabies virus (PRV) was isolated. The mutant, designated as PRV (BUK d13), did not revert to TK-positive (TK+), even when propagated in medium that selected for TK+ viruses. The mutant also replicated equally well at 39.1 C and 34.5 C, and was easily distinguished from other PRV strains by molecular hybridization experiments, restriction nuclease fingerprints, and plaque autoradiography or other assays for the TK phenotype. The PRV (BUK d13) had greatly reduced virulence for mice and rabbits, compared with parental TK+ strains, PRV (BUK-5) and PRV (BUK-5A-R1), and provided mice with solid protection against the TK+ BUK and Aujeszky strains of PRV. Experiments were done in 5- to 6-week-old pigs to assess the safety and efficacy of PRV (BUK d13) in the natural host. In one experiment, pigs were vaccinated IM with 7.5 X 10(8) plaque-forming units of TK- PRV (BUK d13), and were then challenge exposed intranasally (IN) with 4.3 X 10(8) TCID50 of virulent PRV [Indiana-Funkhauser (IND-F)]. Vaccinated pigs did not have clinical signs of illness after vaccination or after challenge exposure. One nonvaccinated control pig died on postchallenge day 4; a 2nd nonvaccinated control pig became moribund, but eventually recovered. Pigs developed virus-neutralizing antibodies after vaccination, and had a secondary immunologic response after challenge exposure; however, PRV was not isolated from the tonsils or trigeminal ganglia of vaccinated pigs at postchallenge exposure day 11.(ABSTRACT TRUNCATED AT 250 WORDS)     

Evaluation in swine of a subunit vaccine against pseudorabies

A subunit vaccine against pseudorabies virus (PRV) was prepared by treating a mixture of pelleted virions and infected cells with the nonionic detergent Nonidet P-40 and emulsifying the extracted proteins incomplete Freund's adjuvant. Three 7-week-old pigs without antibodies against PRV were given 2 IM doses of this vaccine 3 weeks apart. Thirty days after the 2nd vaccination, 10(6) median tissue culture infective doses (TCID50) of a virulent strain of PRV were administered intranasally. Tonsillar and nasal swabs were collected daily between 2 and 10 days after challenge exposure. The pigs vaccinated with the subunit vaccine were not found to shed virulent PRV. Two groups of five 7-week-old pigs vaccinated with commercially available vaccines, either live-modified or inactivated virus, and subsequently exposed to 10(6) TCID50 of virulent PRV, shed virulent virus for up to 8 days. The subunit vaccine induced significantly higher virus-neutralizing antibody titers than either the live-modified or inactivated virus vaccine.     

High- and low-challenge exposure doses used to compare intranasal and intramuscular administration of pseudorabies virus vaccine in passively immune pigs.

We compared 3 modified-live pseudorabies virus (PRV) vaccine strains, administered by the intranasal (IN) or IM routes to 4- to 6-week-old pigs, to determine the effect of high- and low-challenge doses in these vaccinated pigs. At the time of vaccination, all pigs had passively acquired antibodies to PRV. Four experiments were conducted. Four weeks after vaccination, pigs were challenge-exposed IN with virulent virus strain Iowa S62. In experiments 1 and 2, a high challenge exposure dose (10(5.3) TCID50) was used, whereas in experiments 3 and 4, a lower challenge exposure dose (10(2.8) TCID50) was used. This low dose was believed to better simulate field conditions. After challenge exposure, pigs were evaluated for clinical signs of disease, weight gain, serologic response, and viral shedding. When vaccinated pigs were challenge-exposed with a high dose of PRV, the duration of viral shedding was significantly (P less than 0.05) lower, and body weight gain was greater in vaccinated pigs, compared with nonvaccinated challenge-exposed pigs. Pigs vaccinated IN shed PRV for fewer days than pigs vaccinated IM, but this difference was not significant. When vaccinated pigs were challenge-exposed with a low dose, significantly (P less than 0.05) fewer pigs vaccinated IN (51%) shed PRV, compared with pigs vaccinated IM (77%), or nonvaccinated pigs (94%). Additionally, the duration of viral shedding was significantly (P less than 0.05) shorter in pigs vaccinated IN, compared with pigs vaccinated IM or nonvaccinated pigs. The high challenge exposure dose of PRV may have overwhelmed the local immune response and diminished the advantages of the IN route of vaccination.(ABSTRACT TRUNCATED AT 250 WORDS)     

Immune response of pigs inoculated with virulent pseudorabies virus and pigs inoculated with attenuated or inactivated pseudorabies virus vaccine before and after challenge exposure

Pseudorabies virus (PRV) antibodies, detectable by indirect radioimmunoassay (IRIA), serum-virus neutralization test (NT), or microimmunodiffusion test (MIDT) were developed within 8 days after pigs were inoculated with virulent PRV or attenuated PRV vaccine. Indirect radioimmunoassay and NT titers in pigs inoculated with virulent PRV were developed at the same rate, with IRIA titers being higher than NT titers. Pigs inoculated with attenuated or inactivated PRV vaccine developed peak mean prechallenge NT antibody titers of 4 and 1 (reciprocals of serum dilutions), respectively. Pigs inoculated with attenuated PRV vaccine had peak mean prechallenge IRIA antibody titers of 6, whereas pigs inoculated with inactivated PRV vaccine had mean IRIA antibody titers of 64. Challenge exposure of swine inoculated with attenuated or inactivated PRV vaccine elicited quantitatively equivalent responses, as measured by IRIA or NT, which were higher than prechallenge titers. There were no false-positive IRIA, NT, or MIDT results obtained when sera from nonvaccinated, nonchallenge-exposed pigs were tested. It appears that the PRV infection status of a seropositive swine herd could be ascertained by serologically monitoring several representative animals from a herd, using the NT. If 2 or more tests of representative animals at 14-day intervals were done and the mean NT titer was 4 or less, it could be concluded that the herd was vaccinated against, but not infected with, virulent virus.     

Inoculation of pigs with Streptococcus suis type 2 alone or in combination with pseudorabies virus.

Pigs (9 [+/- 1] weeks old) were inoculated with Streptococcus suis type 2, pseudorabies virus (PRV), or both. For each pig of groups A, B, and C the inoculum of S suis was 10(9) colony-forming units. For each pig of groups A, B, and D the inoculum of PRV was 5 x 10(3) TCID50 of either PRV strain 4892 (group A, n = 9) or PRV isolate B (group B, n = 9). The PRV strain 4892 is a highly virulent strain; isolate B causes mild clinical signs of infection in inoculated pigs. Group-C pigs (n = 9) were given S suis alone, and group-D pigs (n = 3) were inoculated only with PRV isolate B. Clinical signs of infection and development of lesions were readily seen in pigs of groups A, B, and C. Duration and severity of clinical signs of disease and lesions were reduced in pigs of group C, compared with those of the other 2 groups. Lesions, such as polyarthritis and fibrinous pericarditis, were more abundant and acute in the groups of pigs given mixed challenge exposure, compared with pigs inoculated exclusively with S suis type 2 (group C). The group of pigs inoculated with PRV isolate B alone did not manifest clinical signs of disease or lesions. Average daily gain for group-C pigs was higher, compared with that of other groups; the difference was statistically significant at P less than 0.02 and P less than 0.05 for groups B and D, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)     

Blocking ELISA to distinguish pseudorabies virus-infected pigs from those vaccinated with a glycoprotein gIII deletion mutant

A blocking enzyme-linked immunosorbent assay (ELISA) test has been developed to distinguish pseudorabies virus (PRV)-infected pigs from those immunized with a glycoprotein g92(gIII) deletion mutant, PRV(dlg92dltk). The blocking ELISA utilizes 96-well microtiter test plates coated with a cloned PRV g92(gIII) antigen, a mouse monoclonal antibody against gIII antigen (moMCAgIII): horseradish peroxidase (HRPO) conjugate, and undiluted test sera. Analyses can be completed in less than 3 hours with results printed out by an automated plate reader. Analyses on over 300 pig sera from PRV-free farms, on sera from other species, and on control sera containing antibodies to microorganisms other than PRV showed that the ratio of the optical density at 405 nm for the test sample to the optical density at 405 nm for the negative control (S/N value) was greater than 0.7 for all sera. No false positives were identified. Likewise, the S/N values were greater than 0.7 for over 400 sera obtained from pigs vaccinated twice with more than 1,000 times the standard PRV (dlg92dltk) dose or 1-4 times with the standard dose (2 x 10(5) TCID50/pig). Following challenge exposure to virulent PRV, the S/N values of the vaccinates were 0.1, showing that g92(gIII) antibodies in the sera of experimentally challenged pigs strongly blocked the binding of the moMCAgIII:HRPO conjugate to the antigen-coated wells. Sera of 233 pigs from PRV-infected herds with virus neutralization (VN) titers of 1:4 or greater were tested. All except 2 of these sera had S/N values less than 0.7 and more than 175 had S/N values less than 0.1. Sixteen sera from fetal pigs with VN titers of 1:4 or greater had S/N values of 0.24 or less, but 2 sera with VN titers of 1:4 when tested 5 years prior to the PRV g92(gIII) blocking ELISA test gave false negative S/N values. Twenty-four of 29 pig sera from PRV-infected herds with VN titers less than 1:4 were positive for g92(gIII) antibodies, illustrating the sensitivity of the PRV g92(gIII) blocking ELISA test. Analyses on 7 sera with VN titers of 1:4-1:64 showed that titers obtained with the PRV g92(gIII) blocking ELISA test were from 2- to 16-fold greater than the VN titers. The accuracy and sensitivity of the PRV g92(gIII) blocking ELISA test was further demonstrated by analyses of 40 unknown sera supplied in the National Veterinary Services Laboratories 1988 PRV check test kit.     

The response of pigs inoculated with a thymidine kinase-negative (TK-) pseudorabies virus to challenge infection with virulent virus

12 Large-White-Landrace piglets were subdivided in four groups of 3 and housed in separate units. The piglets of three groups were inoculated with the 86/27V 6C2 thymidine kinase negative (TK-) mutant of pseudorabies virus (PRV), by different routes. A second inoculation with the same mutant was given to the pigs 21 days later. The animals of a fourth group were left as uninoculated controls. 21 days following the second inoculation with the TK- mutant all pigs were challenge infected with the virulent PRV. On post challenge day (PCD) 30 all pigs were killed and samples for virus detection and histology were taken from several organs. The inoculated TK- mutant of PRV did not induce any ill effects in the pigs except a transient febrile reaction in some animals. Virus was recovered from nasal swabbings from one pig 2 days after the first inoculation of the mutant. After challenge exposure with virulent PRV, the TK- mutant-inoculated pigs were apparently protected, whereas the control pigs all were severely affected and recovered very slowly over 3 weeks. Virus was isolated from the nasal swabbings from the TK- mutant-inoculated pigs on PCDs 2 and 4, whereas the nasal swabbings from the control piglets were all positive for virus from PCD 2 through PCD 10. DNA analysis of the virus recovered showed a pattern identical to that of the virulent PRV. Histologic lesions were found in the respiratory and the central nervous systems, however, the lesions in the TK- mutant-inoculated pigs were much milder compared to those registered for the control pigs. Virus was not isolated from any of the tissue samples that were tested, but viral DNA with sequences typical of PRV genome was detected by PCR in all samples of trigeminal ganglia from either the TK- mutant-inoculated pigs or from the controls.     

Abortion induced by cell-associated pseudorabies virus in vaccinated sows.

Pregnant sows, immune against pseudorabies after vaccination, were inoculated at 70 days of gestation either with autologous blood mononuclear cells that had been infected in vitro with pseudorabies virus (PRV) or with cell-free PRV. The infected cells or cell-free PRV were inoculated surgically into the arteria uterina. Eight sows (A to H) had been vaccinated with an inactivated vaccine. The titer of seroneutralizing antibodies in their serum varied between 12 and 48. Five sows (A to E) were inoculated with autologous mononuclear cells, infected either with a Belgian PRV field strain or with the Northern Ireland PRV strain NIA3. These 5 sows aborted their fetuses: 2 of them (B and C) 3 days after inoculation, and the other 3 (A, D, and E) 10, 11, and 12 days after inoculation, respectively. Sows F, G, and H were inoculated with a cell-free PRV field strain. They farrowed healthy litters after normal gestation. Neutralizing antibodies were absent against PRV in the sera of the newborn pigs, which were obtained prior to the uptake of colostrum. The 23 fetuses that were aborted in sows B and C 3 days after the inoculation were homogeneous in appearance and size. Foci of necrosis were not detected in the liver. Viral antigens were located by immunofluorescence in individual cells in lungs, liver, and spleen of 15 fetuses. Virus was isolated from the liver, lungs, or body fluids of 12 fetuses. The 39 fetuses that were aborted in sows A, D, and E between 10 and 12 days after inoculation were of 2 types: 17 were mummified and 22 were normal-appearing.(ABSTRACT TRUNCATED AT 250 WORDS)     

Antibody response of pigs to inactivated monovalent and bivalent vaccines for porcine parvovirus and pseudorabies virus

Groups of pigs vaccinated with an inactivated bivalent vaccine containing porcine parvovirus (PPV) and pseudorabies virus (PRV) developed geometric mean titers (GMT) of humoral antibody for each of the viruses as high or slightly higher than those of other groups of pigs that were vaccinated with inactivated monovalent vaccines containing one or the other of the same viruses. An increase in GMT after challenge exposure of vaccinated pigs to live virus indicated that vaccination did not prevent virus replication. However, an indication that replication was less extensive in vaccinated pigs was provided by the following. Although neither vaccinated nor nonvaccinated (control) pigs had clinical signs after exposure to the live PPV, the effect of vaccination was evident by the fact that GMT were higher in nonvaccinated pigs after exposure than they were in vaccinated pigs. Conversely, all pigs exposed to live PRV had clinical signs, but these signs varied between mild-to-moderate and transient for vaccinated pigs to severe and fatal for nonvaccinated pigs.     

Hematologic Studies of Rinderpest-Infected Swine

Complete hematologic studies on swine inoculated with virulent rinderpest virus are reported. There was a 67 per cent reduction in total leukocyte counts on the third day postinoculation; counts returned to normal by the eighth day. The remainder of the hematologic values showed no significant changes. There was a febrile response at 3 days postinoculation; by the eighth day, temperature had returned to normal. Other clinical signs were less conspicuous and consisted of anorexia, stiff gait, and arched back occurring only on the third and fourth days after inoculation. The immunity of previously inoculated swine was challenged with virulent rinderpest virus 23 days after initial infection and no abnormal change in hemograms or body temperature resulted. The rinderpest-inoculated groups developed antibodies as demonstrated by the virus neutralization tests in rabbits.     

3种非猪瘟病毒单独或混合感染对猪瘟弱毒疫苗免疫效力的影响

将 2 0头 9月龄左右猪瘟、伪狂犬、猪繁殖与呼吸障碍综合征抗原、抗体阴性猪分成 6组 ,分别利用猪细小病毒(PPV)、猪伪狂犬病毒 (PRV)和猪繁殖与呼吸障碍综合征病毒 (PRRSV)单独或混合感染。 7d后连同对照猪 4头 ,免疫接种猪瘟兔化弱毒疫苗 (HCL V) ,13d后连同 4头阴性对照猪一起攻击猪瘟石门强毒。整个试验期间分别每天测温 ,观察临床症状 ,每周采集扁桃体和血样做各种病毒抗原及抗体检测。结果表明 ,非猪瘟病毒感染 7d后 ,所有各组猪均从体内检测到了相应感染的病原 ,表明 3种非猪瘟病毒感染成功。在攻击猪瘟石门强毒后 2周 ,感染了非猪瘟病毒后接种 HCL V疫苗的 4个免疫组 12头猪除 1头外 ,11头全为猪瘟病毒 (HCV)抗原检测阳性 ,且多呈强阳性 ;而单一 HCL V疫苗免疫组在猪瘟强毒攻击后检测不到 HCV;所有 HCL V疫苗免疫猪均存活 ,而非免疫对照组 4头猪全部在攻毒 16 d内死亡。     

Inoculation of pigs against Trichinella spiralis, using larval excretory-secretory antigens

Pigs were inoculated with Trichinella spiralis excretory-secretory products derived from short-term in vitro maintenance of infective muscle larvae. Intraperitoneal administration of excretory-secretory products in Freund's complete adjuvant or aluminum hydroxide induced moderate, but variable, degrees of immunity to challenge exposure in a nondose-dependent manner; IM administration of products in Freund's incomplete adjuvant was less successful. Inoculated pigs harbored fewer adult worms, and the fecundity of female worms (numbers of newborn larvae shed in vitro) recovered after challenge exposure was significantly lower (alpha = 0.05) than the fecundity of females recovered from control pigs. The degree of resistance in inoculated pigs was directly related to serotiter against excretory-secretory antigens, as determined in an enzyme-linked immunosorbent assay.