Resistance of broiler chickens to Escherichia coli respiratory tract infection induced by passively transferred egg-yolk antibodies

Egg-yolk antibodies induced by immunizing hens with selected Escherichia coli antigens were evaluated for their ability to protect broiler chickens against respiratory/septicemic disease caused by avian pathogenic E. coli (APEC). Seven groups of broiler breeder hens were vaccinated three times, 1 week apart with live E. coli, killed E. coli, E. coli antigens [lipopolysaccharide (LPS), type 1 pilus adhesin (FimH), P pilus adhesin (PapG), aerobactin outer membrane receptor (IutA)] or phosphate buffered saline (PBS). An O78 APEC strain was used for preparation of all the antigens. Egg yolk immunoglobulins (IgY) were purified from eggs of each group and antibody activity in serum and purified IgY was determined by enzyme-linked immunosorbent assay (ELISA). IgY (100mg) was injected intramuscularly into 11-day-old broiler chickens, which were challenged 3 days later with homologous (O78) or heterologous (O1 or O2) E. coli by the intra-air sac route. Mortality was recorded and surviving chickens were euthanized 1 week after the challenge and examined for macroscopic lesions. Passive antibodies against all antigens except FimH were protective (90-100%) against the homologous challenge, but only anti-PapG and anti-IutA were effective against heterologous challenge. Anti-PapG IgY provided the greatest protection against the three serogroups of E. coli used for challenge. Hence vaccination of broiler breeders to induce anti-PapG and anti-IutA antibodies may provide passive protection of progeny chicks against respiratory/septicemic disease caused by APEC.     

Safety,immunogenicity, and efficacy of two Escherichia coli cya crp mutants as vaccines for broilers

Attenuated derivatives (delta cya delta crp mutants) of an O2 and an O78 avian septicemic Escherichia coli strain were used to immunize broiler chickens by spray to determine the safety, immunogenicity, and efficacy of the derivatives in single- and double-dose regimens. In the safety and immunogenicity studies, groups of 10 chickens were vaccinated by spray (droplet size approximately 20 microm) with the parent E. coli, the mutant organisms, or phosphate-buffered saline (PBS) at 14 days of age and euthanatised 21 days later. There was no deaths or gross pathologic finding in any of the chickens immunized with the vaccine strains. Compared with the levels in chickens exposed to PBS, there were significantly higher levels of immunoglobulin (Ig) G antibody in serum and air sac washings and of IgA antibody in air sac washings in response to the virulent parent strains than to the vaccine strains. In efficacy studies, chickens were immunized with the O2 or the O78 vaccine strain or PBS at day 14 and with the O2 vaccine strain or PBS at days 10 and 14 and challenged with the parent strain 10 days after the last vaccination. There was no significant difference in local IgA and IgG and serum IgG responses between vaccinated and control groups. Chickens vaccinated with the O2 strain, but not the O78 strain, had significantly lower air sac lesion scores compared with those of the unvaccinated groups in both single- and double-dose regimens. We conclude that the mutant O2 strain provided moderate protection against airsacculitis.     

Construction, characterization, and evaluation of the vaccine potential of three genetically defined mutants of avian pathogenic Escherichia coli

The delta galE, delta purA, and delta aroA derivatives of avian septicemic Escherichia coli EC99 strain (O78 serogroup) were constructed with a suicide vector containing the pir-dependent R6K replicon and the sacB gene of Bacillus subtilis. The resultant isogenic mutants were stable and lacked approximately 45%, 36%, and 52% of the genes for galE, purA, and aroA, respectively. The delta purA and delta aroA mutants did not grow on minimal medium, whereas the delta galE mutant grew on minimal medium but was sensitive to galactose-induced lysis. The reversion frequencies of all three mutants were <10(-12). The mutants were highly attenuated for virulence as determined by administration of approximately 10(7) colony-forming units of each mutant to 1-day-old chicks by the subcutaneous route. Chickens were vaccinated with the mutants by spray (droplet size approximately 20 microm) at 1 and 14 days of age to determine safety, immunogenicity, and efficacy. The mutants were found to be safe. Seven days after a second vaccination, immunoglobulin (Ig)Y antibodies to E. coli in serum and air sac washings were detected by enzyme-linked immunosorbent assay. In both serum and air sac washings, IgY antibodies were significantly higher in chickens vaccinated with the mutants as compared with phosphate-buffered saline-treated controls but were significantly lower compared with chickens that were vaccinated with the parent strain. In serum, but not in air sac washings, IgY antibodies were significantly lower in chickens vaccinated with the mutants compared with the parent strain. The vaccinated chickens were given infectious bronchitis virus intranasally at 17 days of age and were challenged with homologous (EC99 strain) or heterologous (O2 serogroup) E. coli 4 days later. Chickens that received wild-type EC99 strain or its mutant derivatives were protected from homologous but not from heterologous challenge. This study indicates that the delta galE, delta purA, and delta aroA mutants are safe and moderately immunogenic but the protection conferred by the mutants is serogroup specific.     

Serum and mucosal antibody responses and protection in pigs vaccinated against Mycoplasma hyopneumoniae with vaccines containing a denatured membrane antigen pool and adjuvant

Objective To investigate the protective efficacy of a pool of denatured membrane protein antigens of Mycoplasma hyopneumoniae (J strain) in the molecular size range 70 to 85 kDa (F3 antigen) in combination with adjuvants for pigs challenged with M hyopneumoniae .
Design A vaccine efficacy experiment with assessment of serum and respiratory tract antibody responses.
Procedure F3 antigens were emulsified with five different adjuvants. To groups of three pigs per vaccine, four vaccines were given by intramuscular injection, and two vaccines, including one of those given intramuscularly, were given by intraperitoneal injection.
Results Compared to six unvaccinated pigs, animals vaccinated with F3 antigen displayed significantly reduced pneumonia (54% reduction in mean lung score) following experimental challenge. Analysis of post-vaccination, pre-challenge IgG and IgA ELISA antibody absorbances in serum and respiratory tract washings revealed no correlation with lung score. Six weeks after challenge, pigs previously vaccinated intramuscularly mostly demonstrated greater IgG and IgA responses in respiratory tract washings, and greater IgG serum antibody responses, than those vaccinated by intraperitoneal injection.
Conclusion Pigs vaccinated with M hyopneumoniae antigens in the molecular size range of 70 to 85 kDa showed a significant reduction in lung lesions compared with unvaccinated control animals after experimental challenge. IgG and IgA antibody concentrations in serum and respiratory tract washings after vaccination do not provide a useful prognostic indicator of protection from enzootic pneumonia.     

Recombinant Iss as a potential vaccine for avian colibacillosis

Avian pathogenic Escherichia coli (APEC) cause colibacillosis, a disease which is responsible for significant losses in poultry. Control of colibacillosis is problematic due to the restricted availability of relevant antimicrobial agents and to the frequent failure of vaccines to protect against the diverse range of APEC serogroups causing disease in birds. Previously, we reported that the increased serum survival gene (iss) is strongly associated with APEC strains, but not with fecal commensal E. coli in birds, making iss and the outer membrane protein it encodes (Iss) candidate targets for colibacillosis control procedures. Preliminary studies in birds showed that their immunization with Iss fusion proteins protected against challenge with two of the more-commonly occurring APEC serogroups (O2 and O78). Here, the potential of an Iss-based vaccine was further examined by assessing its effectiveness against an additional and widely occurring APEC serogroup (O1) and its ability to evoke both a serum and mucosal antibody response in immunized birds. In addition, tissues of selected birds were subjected to histopathologic examination in an effort to better characterize the protective response afforded by immunization with this vaccine. Iss fusion proteins were administered intramuscularly to four groups of 2-wk-old broiler chickens. At 2 wk postimmunization, chickens were challenged with APEC strains of the O1, O2, or O78 serogroups. One week after challenge, chickens were euthanatized, necropsied, any lesions consistent with colibacillosis were scored, and tissues from these birds were taken aseptically. Sera were collected pre-immunization, postimmunization, and post-challenge, and antibody titers to Iss were determined by enzyme-linked immunosorbent assay (ELISA). Also, air sac washings were collected to determine the mucosal antibody response to Iss by ELISA. During the observation period following challenge, 3/12 nonimmunized chickens, 1/12 chickens immunized with 10 microg of GST-Iss, and 1/12 chickens immunized with 50 microg of GST-Iss died when challenged with the O78 strain. No other deaths occurred. Immunized chickens produced a serum and mucosal antibody response to Iss and had significantly lower lesion scores than nonimmunized chickens following challenge, regardless of the challenge strain. This study expands on our previous report of the value of Iss as an immunoprotective antigen and demonstrates that immunization with Iss can provide significant protection of chickens against challenge with three different E. coli strains.     

鸡大肠杆菌Ⅰ型菌毛亚单位苗交叉保护的初步研究

含Ⅰ型菌毛的３ 个不同血清型（Ｏ１ 、Ｏ７８ 及Ｏ８８） 的菌株， 大容量培养后提取菌毛制备３ 种单价菌毛油乳苗。用１ 日龄雏鸡分别免疫３ 种单价菌毛油乳剂苗， 每雏免疫量为１２５ μｇ ， 隔离饲养至２ 周龄经气囊攻毒， 并评价疫苗的免疫原性。结果未免疫鸡出现８７－５ ％ ～１００ ％ 的死亡率， 免疫鸡用同源菌株攻毒后死亡率仅１２－５ ％ ， 用异源菌株攻毒出现３７－５％ ～６２－５ ％ 的死亡率。免疫鸡攻毒后未死亡者， 经扑杀观察， 可见在气囊、心包及肝脏的病变非常轻微， 且攻毒后比非免疫鸡能更有效地清除攻入气囊的大肠杆菌     

Immunogenicity of an Escherichia coli multivalent pilus vaccine in chickens

Immunogenicity of an oil-emulsified Escherichia coli multivalent pilus vaccine was evaluated in 4-week-old chickens. The vaccine contained 180 micrograms of pilus protein from each of serotypes O1 and O78 and 170 micrograms of pilus protein from serotype O2. Chickens were vaccinated twice subcutaneously at 4 and 6 weeks old and challenged via the posterior thoracic air sac with E. coli serotype O1, O2, or O78 2 weeks after the last vaccination. Unvaccinated challenged chickens suffered 8% to 26% mortality; no vaccinated chickens died. Vaccinated chickens had very mild gross lesions in the air sacs, livers, and pericardial sacs and eliminated E. coli more efficiently than the unvaccinated challenged chickens. The results showed that a multivalent pilus vaccine protects chickens against active respiratory infection.     

Experimental intramammary inoculation with Mycoplasma bovis in vaccinated and unvaccinated cows: effect on local and systemic antibody response.

Four cows were vaccinated with Mycoplasma bovis five times at two week intervals: three times subcutaneously in Freund's complete adjuvant, and two times with M. bovis alone in two of four quarters by intramammary infusion. The effect of vaccination on the immune response was evaluated in the serum and whey of the four vaccinated and control (placebo) cows experimentally challenged in two of four quarters with live M. bovis. Vaccination resulted in markedly increased M. bovis-specific, serum IgM, IgG and IgG2, but not IgA, reactivity. Challenge exposure with live M. bovis by intramammary infusion resulted in high specific serum IgM, IgG1 and IgG2 reactivity and a noticeable IgA response in both vaccinated and control cows. Whey from quarters on vaccinated cows had elevated, specific IgG1 reactivity at the time of challenge but no other differences were observed. Challenge exposure with live M. Bovis resulted in high antibody levels of all isotypes in quarters which were challenged, but highly elevated reactivities in unchallenged quarters occurred only with IgG1 and IgG2. These results indicate that vaccination elevated M. bovis-specific IgG1 but not other immunoglobulin reactivity in quarters on vaccinated cows, and that live organisms are necessary to elicit a local, specific IgA response.     

Immunogenic potency of an oil-emulsified Escherichia coli bacterin

Immunogenicity of an oil-emulsified Escherichia coli (O1:K1) bacterin with an aqueous-phase-to-oil-phase ratio of 1:4 was evaluated in chickens. Chickens were vaccinated subcutaneously with 0.5 ml of the bacterin at 4 and 6 weeks of age. At 8 weeks, the vaccinated chickens and unvaccinated controls were challenged via air sacs with 10(4) colony-forming units (CFU) of homologous E. coli. Vaccinated chickens were protected against active respiratory infection in that they (a) gained body weights comparable to those in unvaccinated, unchallenged chickens, (b) suffered no morbidity or mortality, (c) had gross lesions so mild that the scored values were comparable statistically to the 0 lesion scores of the negative controls, and (d) did not yield E. coli when their heart blood, pericardial sacs, livers, and air sacs were cultured. Unvaccinated challenged chickens had severe respiratory distress, suffered 36% mortality, and had average air sac, pericardial sac, and liver lesion scores significantly (P less than or equal to 0.05) different from both the vaccinated and negative control chickens. Also, the challenge strain of E. coli only was isolated from the affected tissues of 5 of 14 chickens. Protection against active respiratory infection was again demonstrated in a second experiment, though the challenge dose was 1.06 X 10(6) CFU of E. coli. The immunity, however, was partially overcome, as the vaccinated chickens gained less body weight and the scored values for lesions in the air sacs, pericardial sacs, and livers were significantly higher than those of the negative controls (P less than or equal to 0.05).     

Immunogenicity of Mycoplasma gallisepticum

The serological response and protective immunity elicited in the chicken by the pathogenic Ap3AS strain and the moderately pathogenic 80083 strain of Mycoplasma gallisepticum and variants of strain 80083 attenuated by repeated passage in mycoplasma broth were investigated. Strain 80083 elicited a substantial serum antibody response after administration either in drinking water or by conjunctival sac instillation to 7-week-old SPF chickens. No vaccinated chickens developed air sac lesions when challenged by intra-abdominal (IA) injection with the virulent Ap3AS strain. Chickens vaccinated with strain 80083M (50 broth passages) showed only a weak serological response but were substantially protected when challenged 4 weeks after vaccination. Chickens vaccinated with 80083H (100 broth passages) were serologically negative 4 weeks after vaccination and developed severe air sac lesions after challenge. Thirty-seven-week-old hens vaccinated 6 months previously with strain 80083 had high serum antibody levels and were completely protected against IA challenge with the homologous strain. However, 4/6 showed mild air sac lesions when challenged intra-abdominally with strain Ap3AS. Another group showed high M. gallisepticum serum antibody levels 6 months after vaccination with strain Ap3AS but 4/6 and 2/6 showed mild lesions after IA challenge with strains Ap3AS or 80083, respectively. Strains 80083 or 80083M were administered by conjunctival sac instillation to susceptible 11-week-old commercial pullets at the time of fowl pox vaccination. The concurrent use of both vaccines had no apparent adverse effect on the health of the chickens. Similar protection against IA challenge with strain Ap3AS was produced with the M. gallisepticum vaccines whether used alone or in combination with fowl pox.     

Protection against enteric colibacillosis in pigs suckling orally vaccinated dams: evidence for pili as protective antigens

Pregnant gilts were vaccinated orally with Escherichia coli that produced pilus antigens K99 or 987P. The vaccines were live or dead enterotoxigenic E coli (ETEC) or a liver rough non-ETEC strain which has little ability to colonize pig intestine. Pigs born to the gilts were challenge exposed orally with K99+ or 987P+ ETEC, which did not produce heat-labile enterotoxin or flagella and which produced somatic and capsular antigens different from those of the vaccine strains. Control gilts had low titers of serum and colostral antibodies against pilus antigens, and their suckling pigs frequently had fatal diarrhea after challenge exposure. Serum antibody titers against pilus antigens of the vaccine strains increased in the gilts after vaccination with liver ETEC, and the colostral antibody titers of these gilts were higher than those of controls. Pigs suckling such vaccinated gilts were more resistant than controls to challenge strains were of different pilus types, and it could not be attributed to enterotoxin neutralization by colostrum. In contrast to the live ETEC vaccines given to the pregnant gilts, the liver rough non-ETEC and dead ETEC vaccines stimulated little or no production of antibody against pilu, and the pigs born of these vaccinated gilts remained highly susceptible to challenge exposure. The results support the hypothesis that pilu can be protective antigens in oral ETEC vaccines. It was indicated that in the system reported, protection depended on living bacteria for the production of pilus antigens in vivo or for the transport of pilus antigens across intestinal epithelium.     

Immunogenicity of an Escherichia coli (serotype O1) pili vaccine in chickens

Immunogenicity of an oil-emulsified Escherichia coli (serotype O1) pili vaccine was evaluated in chickens. Chickens were vaccinated with 116 micrograms or 29 micrograms of pili protein and challenged with the homologous E. coli via the posterior thoracic air sac. Unvaccinated chickens were challenged to serve as positive controls or left unchallenged to serve as negative controls. Vaccinated chickens were protected against challenge because they suffered low or no mortality; had mild gross lesions in air sacs, pericardial sacs, and livers, and the scored values were significantly (P less than or equal to 0.05) lower than those in the positive controls; and eliminated E. coli from tissues more efficiently than the positive controls.     

Brucella abortus-specific immunoglobulin in isotypes in serum and vaginal mucus from cattle vaccinated with strain 19 and challenge exposed with virulent strain 2308

The immunoglobulins (IgG1, IgG2, IgM, and IgA) of the Brucella-specific antibody response of 69 crossbred beef heifers were studied after Brucella abortus strain 19 vaccination and strain 2308 challenge exposure. The immunoglobulin isotype responses in serum and vaginal mucus were measured by use of fluorescent immunoassay. Serum antibody responses were detected also by 3 standard serologic tests (complement fixation [CF], Rivanol precipitation, and the CARD test] and 2 primary bindings assays that detect IgG antibodies. One month after vaccination, mean antibody titers for all immunoglobulin isotypes were higher for vaccinated cattle (n = 46) than for nonvaccinated controls (n = 23). After vaccination, IgA antibody responses in vaccinated cattle were only 2-fold higher than those for controls, whereas IgG1, IgG2, and IgM antibody responses were 3- to 90-fold greater than those for controls. Measurement of IgA antibody responses classified 21 of 39 vaccinates as seropositive after vaccination, whereas the other isotypes classified 28 or 34 cattle as seropositive. Three months after challenge exposure, the mean antibody responses for each isotype were higher in cattle that aborted or were culture positive than in cattle that did not abort and were culture negative. Although IgG1, IgG2, and IgM antibody titers were each of benefit in identifying B abortus-infected cattle, it did not appear that the magnitude of the antibody responses provided sufficient discrimination between S19-vaccinated cattle and S2308 challenge-exposed cattle. Serum IgA antibody responses were 10-fold higher after challenge exposure than after vaccination and may be a response to mucosal infection with the virulent organism.(ABSTRACT TRUNCATED AT 250 WORDS)     

Systemic and local immune responses of gnotobiotic calves to respiratory infection with Mycoplasma bovis

Gnotobiotic calves were inoculated by the intratracheal route with Mycoplasma bovis and the specific antibody response in sera and tracheo-bronchial washings examined by radioimmunoassay. In sera an IgM response which reached a peak two weeks post infection was followed by IgG1 and IgG2 antibody responses. Low levels of IgA antibody were detected in sera three and four weeks after infection. The predominant antibody in tracheo-bronchial washings 2 weeks after infection was IgA. Four weeks after infection IgG1 antibody predominated, but IgG2 and IgA antibodies were also present. Cells containing Ig were present in the cellular accumulations around the necrotic zones produced by M. bovis in the lung parenchyma two and four weeks after infection. IgG1 containing cells predominated in these cellular infiltrates. IgG2 producing cells were the next in frequency. It is concluded that the lung lesion caused by M. bovis is partly due to the host's immune response, presumably contributing to the control of the infection, and that the cells infiltrating the lung are a major source of the local and systemic IgG antibody that is detected after infection. IgA staining cells were observed in the submucosa of tissues from nasal cavity and trachea. These cells are probably the source of IgA in tracheo-bronchial washings and sera since IgA-producing cells were not a predominant component of the lesion in the lung parenchyma.     

Cross-protection against Salmonella Typhimurium infection conferred by a live attenuated Salmonella Enteritidis vaccine

In this study, a genetically engineered live attenuated Salmonella Enteritidis (SE) vaccine was evaluated for its ability to protect against Salmonella Typhimurium (ST) infection in chickens. The birds were orally primed with the vaccine on the 1st day of life and given an oral booster at 5 wk of age. Control birds were orally inoculated with phosphate-buffered saline. Both groups of birds were orally challenged with a virulent ST strain at 9 wk of age. Compared with the control chickens, the vaccinated chickens had significantly higher levels of systemic IgG and mucosal IgA against specific ST antigens and a significantly greater lymphoproliferative response to ST antigens. The excretion of ST into the feces was significantly lower in the vaccinated group than in the control group on days 9 and 13 d after challenge. In addition, the vaccinated group had significantly fewer pronounced gross lesions in the liver and spleen and lower bacterial counts in the internal organs than the control group after challenge. These data indicate that genetically engineered live attenuated SE may induce humoral and cellular immune responses against ST antigens and may confer protection against virulent ST challenge.     

Effect of temperature-sensitive Mycoplasma gallisepticum vaccine preparations and routes of inoculation on resistance of white leghorns to challenge

One-week-old chickens were vaccinated with live or formalin-killed temperature-sensitive (TS) Mycoplasma gallisepticum (MG) either intranasally (IN) or subcutaneously (SQ). Live TS MG protected chickens against S6 strain challenge directly into the air sacs, regardless of route of vaccination. Killed MG, however, protected chickens only when administered SQ. Antibody to MG was detected in sera and in the tracheal and air-sac washings of only the chickens given live vaccine IN. The antibody present in tracheal and air-sac washings may be one of the mechanisms that play a role in resistance to MG challenge.     

Immune response to recombinant Escherichia coli Iss protein in poultry

Colibacillosis accounts for significant losses to the poultry industry, and control efforts are hampered by limited understanding of the mechanisms used by avian pathogenic Escherichia coli (APEC) to cause disease. We have found that the presence of the increased serum survival gene (iss) is strongly associated with APEC but not with commensal E. coli, making iss, and the protein it encodes (Iss), candidate targets of colibacillosis control procedures. To assess the potential of Iss to elicit a protective response in chickens against APEC challenge, Iss fusion proteins were produced and administered subcutaneously to four groups of 2-wk-old specific-pathogen-free leghorn chickens. At 4 wk postimmunization, birds were challenged with APEC from serogroups 02 and 078 via intramuscular injection. At 2 wk postchallenge, birds were necropsied, and lesions consistent with colibacillosis were scored. Also, sera were collected from the birds pre- and postimmunization, and antibody titers to Iss were determined. Immunized birds produced a humoral response to Iss, and they had significantly lower lesion scores than the unimmunized control birds following challenge with both APEC strains. Birds that received the smallest amount of immunogen had the lowest lesion scores. Although further study will be needed to confirm the value of Iss as an immunoprotective antigen, these preliminary data suggest that Iss may have the potential to elicit significant protection in birds against heterologous E. coli challenge.     

The protective effect of two porcine enterovirus vaccines in swine.

The virus neutralizing substance in the gastrointestinal tract of swine vaccinated in different ways with porcine enterovirus strain T80 was characterized by tests for enhancement and absorption of virus neutralizing activity by class specific antiporcine Ig antisera. The gastrointestinal virus neutralizing activity of piglets which were vaccinated with live virus orally resided predominantly in the IgA class, although some activity was present also in the IgM and IgG classes. The serum virus neutralizing activity of this group was present in all three classes but primarily in the IgG class. The IgA in the serum of this group was presumably of gut origin. However, in piglets vaccinated with live virus intramuscularly, with formaldehyde-inactivated virus orally or intramuscularly or with ethylenimine-inactivated virus by both oral and subcutaneous routes, both serum and gastrointestinal virus neutralizing activity were attributable predominantly to antibodies of the IgG and IgM classes. None possessed serum IgA. There was evidence also for the presence of Ig fragments in some gastrointestinal extracts.     

Immune response of heifers to vaginal submucosal or subcutaneous vaccination and intravaginal challenge with Ureaplasma diversum.

Twenty beef heifers were randomly assigned to five equal groups and vaccinated: Group 1--in vaginal submucosa (VM) with Ureaplasma diversum ultrasonicated whole cells (WC) in complete Freund's adjuvant (CFA); Group 2--in VM with U. diversum cell membranes (CM) in CFA; Group 3--subcutaneously (SC) with CM in CFA; Group 4--in VM with CM alone; and Group 5--in VM with phosphate buffered saline (PBS) in CFA. A second vaccination with the same antigens in incomplete Freund's adjuvant was given after four weeks, and three weeks later, all heifers were challenged intravaginally with 3.6 x 10(7) colony-forming units (CFU) of U. diversum strain 2312. Immunoglobulins that reacted with U. diversum were measured in serum and cervicovaginal mucus (CVM) by an enzyme-linked-immunosorbent assay. In groups 1 and 2, vaccination by the VM route with WC or CM antigens, stimulated high levels of U. diversum-reactive IgG1 and IgG2 antibodies in serum as well as CVM, but a low IgA response only in CVM. In group 4, VM vaccination with CM (no adjuvant) elicited a minimal IgG1 and IgG2 response in serum and CVM. In group 3, SC vaccination with CM antigen stimulated high IgG1 and IgG2 reactivity in both serum and CVM, but no IgA reactivity. Very little IgM reactivity was detected in the four vaccinated groups. Intravaginal challenge resulted in characteristic granular vulvitis in all vaccinated and control heifers, with all animals remaining culture-positive for the 35 day observation period. The infection stimulated a marked increase in the specific IgA response in CVM of the three groups vaccinated with either, adjuvanted antigen.(ABSTRACT TRUNCATED AT 250 WORDS)     

感染鸡贫血病毒雏鸡接种新城疫疫苗后免疫功能和免疫调节的变化

雏鸡1日龄感染鸡贫血病毒，8日龄接种Lasota疫苗，以未感染免疫雏鸡为对照，于免疫后7、14、28d检测血清免疫球蛋白IgG、IgM、IgA,在凝抑制抗体（HI）滴度；胸腺、法氏囊、脾脏T细胞、IgG^ 、IgM^ 、IgA^ ,抗体生成细胞数量及T、B细胞增殖反应；胸腺、脾脏细胞因子IL－2、IFN活性的变化。结果发现，感染CAV雏鸡Lasota疫苗免疫后，其血清IgG、IgM、IgA免疫球蛋白含量明显减少，HI抗体滴度降低；胸腺、法氏囊、脾脏T细胞、抗体生成细胞数量降低及T、B细胞增殖反应减弱，胸腺、脾脏IL－2及TNF诱生活性降低，表明其细胞免疫和体流免疫功能以及细胞因子免疫调节作用均未感染免疫雏鸡明显减弱。