Newcastle disease virus pathogenesis in the respiratory tract of local or systemic immunized chickens.

Establishment of selective immunity, local or systemic, made it possible to evaluate the pathogenesis of Newcastle disease virus (NDV) in the respiratory tract of chickens that were previously immunized with beta-propiolactone-inactivated antigen. NDV was inoculated intranasally or intramuscularly to chickens in different states of immunity (local or systemic). Humoral antibodies protected chickens against intranasal as well as intramuscular infection. Local antibodies, on the other hand, conferred immunity only against intranasal challenge. The respiratory tract supported multiplication of the virus, producing a self-limited subclinical infection. Replication of the virus in this system was negligible, playing only a minor role in the pathogenesis of the disease.     

Local immunity of the respiratory mucosal system in chickens and turkeys

This review article presents fundamental mechanisms of the local mucosal immunity in selected regions of the respiratory tract in healthy birds and in some pathological conditions. The respiratory system, whose mucosa come into direct contact with microorganisms contaminating inhaled air, has some associated structures, such as Harderian gland (HG), conjunctive-associated lymphoid tissue (CALT) and paranasal glands (PG), whose participation in local mechanisms of the mucosal immunity has been corroborated by numerous scientific studies. The nasal mucosa, with structured clusters of lymphoid tissue (NALT - nasal-associated lymphoid tissue) is the first to come into contact with microorganisms which contaminate inhaled air. Lymphoid nodules, made up of B cells with frequently developed germinal centres (GC), surrounded by a coat of CD4+ cells, are the major NALT structures in chickens, whereas CD8+ cells are situated in the epithelium and in the lamina propria of the nasal cavity mucosa. Studies into respiratory system infections (e.g. Mycoplasma gallisepticum) have shown the reactivity of the tracheal mucosa to infection, despite a lack of essential lymphoid tissue. Bronchus-associated lymphoid tissue (BALT) takes part in bronchial immune processes and its structure, topography and ability to perform defensive function in birds is largely age-dependent. Mature BALT is covered by a delicate layer of epithelial cells, called follicle-associated epithelium (FAE). Germinal centres (GC), surrounded by CD4+ cells are developed in most mature BALT nodules, while CD8+ lymphocytes are dispersed among lymphoid nodules and in the epithelium, and they are rarely present in GC. Macrophages make up the first line of defence mechanisms through which the host rapidly responds to microorganisms and their products in the respiratory mucosal system. Another very important element are polymorphonuclear cells, with heterophils being the most important of them. Phagocytic cells obtained from lung lavages in birds are referred to as FARM (free avian respiratory macrophages). Their number in chickens and turkeys is estimated to be 20 times lower than that in mice and rats, which indicates a deficit in the first-line of defence in the birds' respiratory system. There are numerous B cells and antibody secreting cells (ASC) present throughout the respiratory system in birds. Their role comes down to perform antigen-specific protection by producing antibodies (IgM, IgY or IgA class) as a result of contact with pathogenic factors.     

Salmonella flagellin enhances mucosal immunity of avian influenza vaccine in chickens

Flagellin, a bioactive Toll-like receptor (TLR) 5 ligand, may trigger the innate immunity that in turn is important for subsequent adaptive immune responses. In the present study, the adjuvant effects of the monomeric and polymeric forms of Salmonella flagellin (mFliC and pFliC, respectively) were examined in specific-pathogen free (SPF) chickens immunized intramuscularly (i.m.) or intranasally (i.n.) with formalin-inactivated avian influenza virus (AIV) H5N2 vaccines. Results showed that mFliC cooperating with the 64CpG adjuvant significantly induced influenza-specific antibody titers of plasma IgA in the i.m.-vaccinated animals. The nasal IgA levels in the i.n.-mFliC-coadministrated AIV vaccinated chickens were significantly elevated compared to levels observed in the control group (H5N2 vaccine alone). The pFliC cooperating with the 64CpG adjuvant significantly enhanced cell proliferation of splenocytes in the i.m.-vaccinated animals. TLR3 and TLR5 expressions were activated by flagellin stimulation in vitro and in vivo. These results suggest that flagellin can be used as an adjuvant in an AIV H5N2 vaccine, especially for mucosal immunity.     

The effect of infectious bursal disease virus infection on local and systemic antibody responses following infection of 3-week-old broiler chickens

Broiler chickens infected at 3 weeks of age with infectious bursal disease virus (IBDV) were given Brucella abortus (BA) or sheep red blood cell (SRBC) antigens before, during, and after the acute phase of the infection. Gland of Harder (GH) extracts and serum samples were used to assay local and systemic antibody titer to each antigen 7 days after antigen was administered. Antibody titers to both BA and SRBC antigens were lower (P less than 0.05) in GH extracts and serum of IBDV-infected broilers than uninfected controls. The responses to BA, a thymus-independent antigen, took longer to become depressed than the responses to SRBC, a thymus-dependent antigen. The depression of antibody titers following IBDV inoculation suggests compromise of both local and systemic immune function, a finding of importance to the broiler industry.     

ISCOM-matrix-based equine influenza (EIV) vaccine stimulates cell-mediated immunity in the horse

The humoral immune response induced by ISCOM-matrix (Immuno Stimulating COMplex-Matrix)-adjuvanted equine influenza virus (EIV) vaccine is well documented in horses. ISCOM-matrix adjuvanted vaccines against human influenza are strong inducers of cell-mediated immunity (CMI), including T cell proliferation and virus-specific cytotoxic T cell. In the horse, the CMI response to equine influenza vaccination is less well characterised. An ISCOM-based vaccine has been shown to induce interferon gamma (IFN-γ) synthesis, a CMI marker, in the horse, but this has not been shown for the ISCOM-matrix vaccine, which is a different formulation. The objective of this study was to measure EIV-specific IFN-γ synthesis after vaccination with an ISCOM-matrix-adjuvanted EIV vaccine. Equilis Prequenza is a commercialised inactivated EIV vaccine containing purified haemagglutinin (HA) and neuraminidase (NA) subunits adjuvanted with ISCOM-matrix. Six influenza-naïve Welsh mountain ponies were vaccinated twice with Equilis Prequenza at an interval of four weeks. Six control ponies received a placebo of physiological water. EIV-specific IFN-γ synthesis by peripheral blood lymphocytes and the antibody response to a panel of representative EIV isolates were measured prior to and after both injections. Immunisation with the ISCOM-matrix-based EIV vaccine stimulated significant EIV-specific IFN-γ synthesis and EIV-specific single radial haemolysis (SRH) antibody. In conclusion, EIV vaccine adjuvanted with ISCOM-matrix stimulates both antibody and a cellular immune response in the horse.     

Limited susceptibility and lack of systemic infection by an H3N2 swine influenza virus in intranasally inoculated chickens

Chickens were intranasally inoculated with the swine influenza virus (SIV) A/swine/NC/307408/04 (H3N2) (NC/04 SIV) to determine the infectivity of a North American SIV for chickens, as well as the possibility of chicken meat serving as a transmission vehicle for SIV. White leghorn (WL) layer-type chickens were used for initial pathotyping and infectivity tests, and a more comprehensive intranasal pathogenesis study was done with white Plymouth rock (WPR) broiler-type chickens. None of the NC/04 SIV-inoculated WL or WPR chickens displayed clinical signs. Serologic tests showed that the virus was able to infect both intranasally inoculated WL and WPR chickens, but the antibody titers were low, suggesting inefficient replication. Some of the NC/04 SIV-inoculated WL chickens shed low levels of virus, mostly from the alimentary tract, but viral shedding was not detected in NC/04 SIV-inoculated WPR chickens. The comprehensive pathogenesis study demonstrated that the virus did not cause systemic infections in WPR chickens, and feeding breast and thigh meat from the NC/04 SIV-inoculated WPR to WL chickens did not transmit NC/04 SIV.     

In vivo function tests of the effect of tilorone and niridazole on cell-mediated immunity in chickens.

The need for effective, safe, specific cellular immune suppression in avian research led to the study of effects of tilorone and niridazole on cell-mediated immunity of chickens. Two in vivo tests for cell-mediated immunity function were used--the graft-vs-host (GvH) test and the delayed hypersensitivity (DH) test. Humoral immunity was evaluated by measuring natural hemagglutination (HA) titers against rabbit red blood cells. Intraperitoneal administration of tilorone to young chickens appeared to have severe toxic side effects and was of little value as an immune suppressant. Oral administration of tilorone to 6-week-old chickens caused DH suppression, but no marked effect was seen on GvH reactions or HA titers. Toxicosis appeared less severe. Oral administration of niridazole to 6-week-old birds caused nearly complete loss of GvH and DH reactivity but caused an increase in HA titers. General toxic effects of niridazole were not apparent.     

Adenovirus infection associated with respiratory disease in commercial chickens

The lesions and etiologic agents associated with 13 outbreaks of respiratory disease in commercial chickens were investigated. Adenoviruses were isolated from tracheal and lung tissues of affected chickens in all 13 outbreaks. Escherichia coli was isolated from the lung of an occasional bird. The tracheal specimens were consistently negative for Bordetella avium, but E. coli and occasionally Staphylococcus aureus were isolated. There was also serological evidence in one outbreak, and pathological evidence in another, of a concurrent infectious bursal disease virus (IBDV) infection of chickens affected with the disease. Gross and microscopic alterations in the tracheas and lungs of affected chickens were similar in all outbreaks and consisted of catarrhal tracheitis and occasionally multifocal pneumonia with mononuclear cell infiltrates. Hepatitis and splenitis with heterophil infiltrates occasionally were seen in birds with coliform septicemia. The tracheal and lung lesions in the present investigation were considered primarily of adenovirus etiology, complicated by secondary bacterial infection.     

Specific cell-mediated immunity in fish

This review describes the fish immune system, focusing on specific cell-mediated immunity. Specific in vivo cell-mediated immune responses have been shown by allograft rejection, graft-versus-host reaction (GVHR) and delayed hypersensitivity reaction (DTH). Recent in vitro studies also showed specific cell-mediated cytotoxicity against allogeneic target cells. These in vivo and in vitro experiments strongly suggest the presence of cytotoxic T cells in fishes. Also described are current studies on shark and trout MHC class I polymorphism and function that demonstrate strong similarities between fish and mammals.     

REV和ALV-J感染对肉用型鸡细胞免疫反应的影响

以网状内皮增生症病毒（REV）和禽白血病病毒J亚群（ALV-J）单一感染和共感染1日龄商品代AA肉鸡后不同时间,采用3H-TdR掺入法测定血液和脾脏的淋巴细胞对ConA的增殖反应能力。结果表明,血液淋巴细胞对ConA增殖反应能力在REV和ALV-J共感染后7 d均下降,REV单一感染组在感染后17、37 d均极显著低于对照组（P〈0.01）,ALV-J单一感染组也呈现下降趋势。在脾淋巴细胞反应中,REV感染组在感染后37 d极显著降低（P〈0.01）,ALV-J组显著降低（P〈0.05）。REV和ALV-J共感染抑制淋巴细胞对ConA增殖反应较单一感染强,效应期也较长,在感染后37 d,共感染对血液和脾淋巴细胞反应的抑制作用均大于REV和ALV-J的单一感染（P〈0.05）。在感染后273、7 d检测NDV抗体,单一感染组降低显著（P〈0.05）,而共感染组下降极显著（P〈0.01）,且显著低于单一感染组（P〈0.05）。本研究表明REV、ALV-J感染不仅能抑制体液免疫反应,也能抑制细胞免疫反应,且共感染比单一感染的抑制作用更强。     

Bacteriophage treatment of a severe Escherichia coli respiratory infection in broiler chickens

A bacteriophage to a serotype 02, nonmotile Escherichia coli was isolated from municipal waste treatment facilities and poultry processing plants. A study was conducted to determine the efficacy of multiple vs. single intramuscular (i.m.) injections of bacteriophage to treat a severe E. coli respiratory infection. The birds were challenged at 7 days of age by injection of 6 x 10(4) colony-forming units (cfu) of E. coli into the thoracic air sac followed by an i.m. injection into the thigh with either heat-killed or active bacteriophage. There were 16 treatments with three replicate pens of 10 birds. There were four control treatments, which included untreated birds, birds injected with either heat-killed or active bacteriophage, and birds challenged only with E. coli. In the remaining treatments, birds were injected with heat-killed or active bacteriophage either once immediately after E. coli challenge or immediately after challenge and at 8 and 9 days of age, once at 8 days of age or at 8, 9, and 10 days of age, and once at 9 days of age or at 9, 10, and 11 days of age. Mortality was significantly decreased from 57% to 13% in the birds given a single i.m. injection of bacteriophage immediately after E. coli challenge, and there was complete recovery in birds treated immediately after challenge and at 8 and 9 days of age, which was a significant improvement from the single injection treatment. There was a significant reduction in mortality from 57% to 10% in the birds treated with bacteriophage once at 8 days of age and those birds treated at 8, 9, and 10 days of age, with no difference between single or multiple treatments. The mortality in the single or multiple phage treated birds that started at 9 days of age was reduced from 57% to 28% and 27%, respectively, but was not statistically different from the control. These data suggest that bacteriophage can be an effective treatment when administered early in this experimental E. coli respiratory disease and that early multiple treatments are better than a single treatment. The efficacy of bacteriophage treatment diminishes as it is delayed, with no difference between single or multiple treatments. Bacteriophage may provide an effective alternative to antibiotics, but like and biotic therapy, the effectiveness of phage to rescue animals decreases the longer treatment is delayed in the disease process.     

不同品种地方鸡对柔嫩艾美球虫的易感性分析

按每只鸡12×10~4个孢子化卵囊的剂量,分别感染20日龄大骨鸡、鹿苑鸡、油鸡和固始鸡,以存活率、相对增重率、血便扣分、病变扣分、卵囊扣分和抗球虫指数为评价指标,分析比较4个地方品种鸡对柔嫩艾美球虫的易感性。试验重复1次。结果显示,4个地方品种鸡对柔嫩艾美球虫的易感性不同。固始鸡对柔嫩艾美球虫易感性最高,表现为感染后的死亡率最高,病变扣分最多,抗球虫指数也最低。油鸡对柔嫩艾美球虫的易感性最低,表现为感染后的死亡率为零,病变扣分和血粪扣分最少,每鸡平均排卵囊数最少,抗球虫指数最高。大骨鸡和鹿苑鸡对柔嫩艾美球虫的易感性相近,位于固始鸡与油鸡之间。     

A DNA vaccine coding for glycoprotein B of pseudorabies virus induces cell-mediated immunity in pigs and reduces virus excretion early after infection

Glycoproteins B (gB), gC and gD of pseudorabies virus (PRV) have been implicated as important antigens in protective immunity against PRV infection. As cell-mediated immunity plays a major role in this protective immunity, we determined the significance of these glycoproteins in the actual induction of cell-mediated immunity. We vaccinated pigs with plasmid DNA constructs coding for gB, gC or gD and challenged them with the virulent NIA-3 strain of pseudorabies virus. Vaccination with plasmid DNA coding for gB induced the strongest cell-mediated immune responses including cytotoxic T cell responses, whereas plasmid DNA coding for gD induced the strongest virus neutralising antibody responses. Interestingly, vaccination with gB-DNA reduced virus excretion early after challenge infection while vaccination with gC-DNA or gD-DNA did not.This is the first study to demonstrate that DNA vaccination induces cytotoxic T cell responses in pigs and that cell-mediated immunity induced by vaccination with gB-DNA is important for the reduction of virus excretion early after challenge infection.     

Systemic and local antibody responses after experimental infection with Actinobacillus pleuropneumoniae in piglets with passive or active immunity

The objectives of the present study was to describe different dynamics of humoral immune responses to experimental infection in piglets of different stages of infection and immunity. Two groups of piglets originating from non-immune (group 1) and immune (group 2) sows at the age of 3 weeks were subdivided as follows: a half of each group of piglets was exposed to a low-dose infection with Actinobacillus pleuropneumoniae (APP) strain 9. At the age of 8 weeks, all four groups of piglets were challenged with a high infection dose of APP of the same strain. Isotype characterization of the specific antibodies in sera and in bronchoalveolar lavage fluids (BALF) to a lipopolysaccharide was carried out, besides monitoring clinical signs and post-mortem examinations. A typical primary immune response was observed in specific antibody-free piglets infected with a challenge infection. Colostrum-derived immunoglobulin-G (IgG) antibodies persisted in sera and BALF of piglets up to the age of 8 weeks. However, they did not prevent induction of specific-primary antibody response, either in 8 or 4 weeks of age, when levels of specific colostrum-derived antibodies were still high. It was demonstrated by the increase of specific IgM antibodies in sera. The infection induced an increase in the levels of IgA antibodies in BALF regardless the severity of infection and presence of specific colostrum-derived antibodies. The specific antibodies of IgG isotype increased only in BALF from piglets without colostrum-derived antibodies.     

鸡的气雾免疫

气雾免疫,省工省力,且对呼吸道有亲嗜性的疫苗特别有效(例如鸡新城疫Ⅱ、Ⅳ系弱毒疫苗和传染性支气管炎弱毒疫苗等),所以近年来采用气雾免疫的鸡群正在逐渐增多。     

Duration of circulating antibody and immunity following infection with equine influenza virus

The duration of immunity as measured by virological, serological and clinical responses following infection with influenza A/equine/Newmarket/79 (H3N8) was assessed in repeated challenge experiments in which ponies were infected by exposure to aerosols of infectious virus. Previous infection stimulated complete clinical protection which persisted for at least 32 weeks as demonstrated by the absence of febrile responses and coughing in two groups of ponies infected 16 weeks or 32 weeks after the first infection. Partial clinical protection persisted for over a year as demonstrated by the absence of coughing and a reduction in the number of febrile responses in a group of ponies infected 62 weeks after their first infection. These results contrasted with those observed in immunologically naive control ponies which developed pyrexia, dyspnoea and nasal discharge and coughing. The kinetics of virus specific antibody production in primary and secondary infections with equine influenza were studied by the single radial haemolysis test and a radioisotopic antiglobulin binding assay which measured virus specific IgGab antibody isotype. Antibody to the haemagglutinin, as measured by the single radial haemolysis test, declined rapidly after primary infection whereas the IgGab responses to whole virus antigens persisted for longer. The single radial haemolysis test was therefore particularly useful for the detection of antibody responses in multiple infections or exposures to influenza antigens. The radioisotopic antiglobulin binding assay was more sensitive for identifying infections which had occurred more than six months previously, as evidenced by anamnestic IgGab responses in ponies with low levels of antibody before rechallenge.     

Lachrymal antibody response of specific pathogen free chickens and chickens with maternal immunity after infectious bronchitis virus vaccination

Lachrymal fluid specific IgG and IgA were detected by ELISA in chickens with specific maternal antibodies and in chickens free of antibodies (SPF), after vaccination at 1 day of age with the H-120 vaccine strain of infectious bronchitis virus. Samples were obtained at 3 day intervals and until Day 37 of age. Optical densities were in all instances low but significant differences could be detected within and between the experimental groups. Both class-specific immunoglobulins showed a similar kinetic pattern. Nevertheless, the SPF group increased its IgA level on Day 13 while chickens with maternal immunity increased their level on Day 16. The antibody levels of both IgG and IgA were also different, being higher in the SPF group. In both chicken groups, higher levels of IgA than IgG were detected.     

Lesions in broiler and layer chickens in an outbreak of highly pathogenic avian influenza virus infection

Fifteen chickens, five broilers and ten layers, from the Pennsylvania 1983 outbreak of highly pathogenic avian influenza virus infection, were examined. Gross lesions in the broilers were limited to serosal petechiae and dehydration. In the layers there was comb edema, vesiculation, and necrosis. Microscopic lesions were mild to severe diffuse nonsuppurative encephalitis, very mild to severe diffuse necrotizing pancreatitis, and very mild to severe subacute necrotizing myositis involving numerous skeletal muscles and most severe in the external ocular muscles and limbs. While many of these lesions have been seen in experimental infections of chickens with influenza viruses, the pattern of organs involved in this group of chickens is distinctive.     

T cell mediated and humoral immunity in a mouse Chlamydia psittaci systemic infection

Immunity against Chlamydia psittaci, an obligate intracellular parasite, was studied in a mouse model of systemic infection. Sera (0.1 ml) and splenic cells (2 X 10(8)) from immunised mice were given intravenously to susceptible mice 16 hours before intravenous challenge with 1 X 10(5) plaque forming units (pfu) of virulent strain AB7. Transfer of immune cells primed with virulent strain AB7 or vaccinal strain 1B, lowered splenic and hepatic colonisation by approximately 5.5 log pfu. Treatment of immune cells with antithymocyte serum plus complement, before transfer, abrogated the protection. Transfer of sera raised against the virulent strain AB7, or the attenuated vaccinal strain 1B, lowered hepatic colonisation by approximately 1.5 log pfu. Sera containing antigenus antibodies, raised against heat-killed chlamydiae from strain AB7 or the non-virulent intestinal strain iB1, were not protective. Cellular immunity is mainly responsible for the observed protection, although humoral immunity may play some role.