IBDV-induced bursal T lymphocytes inhibit mitogenic response of normal splenocytes

We examined the suppressive activity of bursal T cells induced by infectious bursal disease virus (IBDV) in inbred (15x7) and outbred commercial specific-pathogen-free (SPF) chickens. The suppressive activity was measured by the ability of bursal and splenic T cells from IBDV-infected chickens to inhibit mitogenic responses of normal splenocytes. The bursacytes but not the splenocytes of IBDV-infected chickens inhibited the mitogenic responses of normal splenocytes. The mitogenic inhibition by the bursacytes of IBDV-infected chickens was dose-dependent. The suppression was observed both in inbred and non-inbred chickens, and thus, was non MHC-restricted. Cell-sorting experiments revealed that both CD4(+) and CD8(+) cells from the bursa of IBDV-infected chickens, as well as cell-culture supernatants conditioned by these cells, mediated suppression. Suppressor T (Ts) cells may therefore be involved in the immunosuppression induced by IBDV.     

Susceptibility of ducks and duck-origin cell cultures to infectious bursal disease virus

Specific-pathogen-free (SPF) ducks that were 1, 3, 4, 7, 10, 30, and 180 days old were inoculated experimentally orally or nasally with infectious bursal disease virus (IBDV). Attempts to induce clinical disease in ducks with strain J1 or FK-78 of IBDV were unsuccessful. Virus-recovery attempts from organ and intestinal contents were also unsuccessful. No significant gross or histopathological lesions were found in liver, spleen, kidney, heart, or bursa of Fabricius of 1- and 3-day-old ducks at 4 or 7 days postinoculation. The ratios of bursa weight to body weight of 1-, 10-, and 30-day-old inoculated and control ducks revealed no difference at 21 days postinoculation. The ducks responded serologically, however, by developing both virus-neutralizing and agar-gel-precipitin antibodies. Virus multiplied in embryonated duck eggs and duck embryo fibroblast cells but not in duck kidney cells.     

Distribution of immunoglobulin-bearing cells in the gut-associated lymphoid tissues of the turkey: effect of antibiotics

Distribution of immunoglobulin (Ig)-bearing cells in the gut-associated lymphoid tissues of antibiotic treated and untreated control turkeys (Meleagris gallopavo) was compared. Antibiotic treatment was similar to a regimen used in commercial turkey production, which included preincubation dipping of fertile eggs in gentamicin solution, injection of turkeys with gentamicin at hatching, and inclusion of chlortetracycline in the diet. Tissues were examined from turkeys at 3, 7, 14, and 21 days of age with a direct immunofluorescence procedure. Cell distribution in control turkeys was as follows: In the bursa of Fabricius, IgA-carrying cells predominated at 3 days of age, but at later intervals, the 3 classes of Ig-bearing cells were in equal numbers. In the cecal tonsils, IgM- and IgA-bearing cells were in larger numbers at 3 days of age, whereas, the IgG-bearing cells were sparsely distributed. By 7 days of age, IgM cells became more numerous in the cecal tonsils and remained numerous until 21 days of age. At 3 days of age, IgA cells predominated in the small intestines and IgM cells predominated in the large intestine. At 7 and 14 days of age, IgM cells were more numerous in the small and large intestines, but by 21 days of age, IgA cell population equaled that of IgM. The IgG cells were generally sparse in the intestines. Antibiotic treatment often resulted in lower numbers of Ig-positive cells, especially those bearing IgM and IgA. Normal development of the bursa of Fabricius was also retarded in this group.     

Regulatory T cell properties of thymic CD4(+)CD25(+) cells in ducks

Thymic CD4(+)CD25(+) cells from ducks were characterized for mammalian T regulatory cells' suppressive and cytokine production properties. The cross reactivity of anti-chicken CD25 monoclonal antibody with duck CD25 was confirmed by evaluating Concanavalin-A-stimulated CD25 upregulation in splenocytes. CD4(+)CD25(+) cells were detectable in the thymus, spleen, cecal tonsil, and lung (airsacs), but not in the bursa. Duck CD4(+)CD25(+) cells had approximately nine-fold higher IL-10 mRNA, 12-fold higher TGF-β, 16-fold higher CTLA-4, and nine-fold higher LAG-3 mRNA amounts than thymic CD4(+)CD25(-) cells. Thymic CD4(+)CD25(+) cells had no detectable levels of IL-2 mRNA. Duck CD4(+)CD25(+) cells had a three-fold higher IL-10 mRNA amount than chicken CD4(+)CD25(+) cells. Duck CD4(+)CD25(+) cells were anergic in vitro. Duck CD4(+)CD25(+) cells suppressed naive cell proliferation at effector: responder cell ratios above 0.5:1 in both contact-dependent and -independent pathways. It could be concluded that thymic CD4(+)CD25(+) cells in ducks are most likely the counterpart of mammalian T regulatory cells.     

Comparative immunopathogenesis of mild,intermediate, and virulent strains of classic infectious bursal disease virus

Differences in the immunopathogenesis of several strains of infectious bursal disease virus (IBDV) were compared. The strains included a virulent virus (IBDV-IM) and three vaccine viruses that included an intermediate vaccine virus (IBDV-B2) and two mild vaccine viruses (IBDV-Lukert and IBDV-BVM). The most significant differences were found in the systemic effects of these strains. In comparison with other strains, IBDV-IM antigen was detectable for up to 8 days postinfection (PI) in lymphoid tissues that included spleen and cecal tonsils, whereas only a few IBDV-B2- and IBDV-Lukert- and no IBDV-BVM-inoculated birds had detectable IBDV antigen in these tissues. IBDV-IM induced systemic circulating nitrite levels in over 86% of the birds at days 2 and 3 PI. IBDV-IM suppressed most vigorously the splenic mitogenic response on days 3-8 PI. Among the three vaccine strains, IBDV-B2 was the most virulent of the three, inducing a significant suppression of the mitogenic response (P < 0.05) and the most vigorous lesions in the bursa of Fabricius with the highest possible lesion score of 4 at 3 days PI (P < 0.05). IBDV-BVM was the mildest strain, not inducing any detectable lesions in lymphoid tissue at the tested time points. Whereas all IBDV-BVM-inoculated and 67% and 33% of the IBDV-Lukert- and IBDV-B2-inoculated birds, respectively, had detectable IBDV antigen in the bursa at 4 days postchallenge, none of the IBDV-IM-inoculated birds was positive for IBDV by immunohistochemistry. IBDV-IM induced the highest enzyme-linked immunosorbent assay (ELISA) antibody levels detected at days 8-29 PI (P < 0.05) and the best protection against challenge virus replication in comparison with IBDV-B2 and IBDV-Lukert. Only one of five IBDV-BVM-inoculated birds developed anti-IBDV ELISA antibodies at 29 days PI, and none of the birds was protected against IBDV challenge. We speculate that better protection with more virulent strains was due to more systemic antigenic stimulation on the basis of higher replication of IBDV in extrabursal lymphoid tissues. Interestingly, IBDV-IM did not differ from IBDV-B2 and IBDV-Lukert in its ability to induce T cell accumulation in the bursa at 8 days PI and local interferon-gamma induction from days 2 to 5 PI. These results suggested that the local T cell events in the bursa alone may not be indicative of a rapid and protective immune response.     

Immune dysfunction following infection with chicken anemia agent and infectious bursal disease virus. I. Kinetic alterations of avian lymphocyte subpopulations.

The potential effect of chicken anemia agent (CAA) alone or in combination with infectious bursal disease virus (IBDV) on the immune system of young chickens was determined by measuring alterations in hematocrit values, lymphoid organ-to-body weight ratios and lymphoid cell concentrations at 4, 7, 10, 14, 17, 21, 28 and 42 days post-inoculation (PI). Lymphocyte subpopulations were identified and counted by flow cytometry using cell suspensions stained with monoclonal antibodies (Mabs) for panlymphocytes (K55), cytotoxic T-cells (CTLA3), T-helper cells (CT3), Ia-expressing cells (P2M11) and macrophages (P7). Chicken anemia agent induced a substantial but transient decrease in hematocrit value, thymus-to-body weight ratio and bursa-to-body weight ratio between 7 and 21 days PI corresponding to a generalized lymphocytopenia in the thymus, bursa and spleen. However, cytotoxic T-cell, T-helper cell and Ia-expressing cell concentrations increased in the bone marrow of birds inoculated with CAA alone or in combination with IBDV during the same time period. T-helper-to-cytotoxic T-cell ratios increased in the thymus and spleen during severe lymphocytopenia, indicating a selective decrease in cytotoxic T-cells. T-helper-to-cytotoxic T-cells ratios increased in the bone marrow, indicating a selective increase in T-helper cell concentrations. The increase in Ia-expressing cells in the bone marrow may be a reflection of increased number of activated T-cells which express Ia antigen. Infectious bursal disease virus alone induced a persistent depression of Ia-expressing cells in the bursa and the spleen and no measurable change in the bone marrow lymphocyte subpopulations. Chickens inoculated simultaneously with CAA and IBDV experienced clinical signs observed in chickens inoculated with each virus separately with a prolonged acute phase prior to recovery or mortality.     

Gamma/delta T cell response of chickens after oral administration of attenuated and non-attenuated Salmonella typhimurium strains

Poultry represents an important source of Salmonella infection in man. Despite intensive research on immunity, little is known about the involvement of T cell sub-populations in the immunological response of chickens against infection with non-host-adapted Salmonella (S.) serovars. In this study, the T cell composition of blood lymphocytes (CD4(+)CD8(+); CD4(+)CD8(-); CD4(-)CD8(+); CD8(+)TcR1(+); CD8(-)TcR1(+), CD8(+)TcR1(-)) after oral administration of the non-attenuated S. typhimurium wild-type strain 421 (infection) or the attenuated vaccine strain Salmonella vac((R)) T (immunization) to day-old chicks was investigated and compared with non-treated chickens by flow cytofluorometry. Additionally, the occurrence of T cell sub-populations (CD4(+); CD8(+); TcR1(+)(gammadelta); TcR2(+)(alphabeta(1))) in ceca, spleen and bursa of Fabricius of the birds was studied immunohistologically. Blood samples and tissues were examined between days 1 and 12 of age.Chicks inoculated with S. typhimurium 421 or Salmonella vac((R)) T showed significantly elevated percentages of CD8(+)TcR1(+) in blood on days 7, 8 and 9, or on day 8 in comparison to control animals. The CD4 to CD8 cell ratio was about 3:1 in infected animals on day 5 of age. In the organs of treated chicks the numbers of CD8(+)(gammadelta) and TcR1(+)(gammadelta) cells had markedly increased on days 4 and 5 in ceca, 8 and 9 in the bursa and 9 and 12 in the spleen. Moreover, infected or vaccinated birds revealed larger quantities of CD4(+) and TcR2(+) T cells in ceca on days 4 and 5. As shown by double staining, the TcR1(+) cells in the organs of infected animals additionally carried the CD8 antigen.In conclusion, immunization of day-old chicks with the attenuated Salmonella live vaccine strain resulted in the same changes in T cell composition as seen after infection with the non-attenuated Salmonella wild-type strain, but at a lower level. The remarkable increase of CD8(+)TcR1(+)(gammadelta) double positive cells in treated birds indicates an important role of this cell sub-population in the immunological defense of chickens against Salmonella exposure.     

Viral and bacterial agents associated with experimental transmission of infectious proventriculitis of broiler chickens.

Proventriculitis of broilers can be reproduced by oral inoculation of day-old chicks with a proventricular homogenate from affected 3-wk-old broilers. The objective of the following studies was to isolate from this homogenate viral and bacterial isolates that could produce proventriculitis. A monoclonal antibody to infectious bursal disease virus (IBDV) was used to precipitate virus from the homogenate. A primary chicken digestive tract cell culture system was also used to isolate virus from a 0.2-microm filtrate of the homogenate, and a bacterium was also isolated from the homogenate. In trial 1, day-old birds were orally inoculated with either proventriculus homogenate or monoclonal antibody immunoprecipitated IBDV (MAB-IBDV). At 4, 7, 14, and 21 days postinfection (PI), 12 birds from each treatment group were subjected to necropsy. In trial 2, day-old birds were orally inoculated with either infectious proventriculus homogenate, suspect virus isolated in cell culture and propagated in embryo livers and spleens, or a bacterial isolate. Twelve birds from each treatment were subjected to necropsy at days 7, 14, 21, and 28 PI. In trial 3, treatments were maintained in negative pressure isolation chambers, and an additional treatment included virus plus bacterial isolate. Twenty-four birds from each treatment were subjected to necropsy at day 21 PI. In trial 1, infectious homogenate decreased body weight and relative gizzard weights at 4, 7, 14, and 21 days PI. Proventriculus relative weight was increased at days 7, 14, and 21 PI, and proventriculus lesion scores were increased at days 14 and 21 PI. Bursa/spleen weight ratios were decreased at day 14, and feed conversion was increased at days 4 and 21. The MAB-IBDV treatment decreased proventriculus and gizzard relative weights at day 4 PI, increased proventriculus lesion scores and bursa/spleen weight ratios at day 14, and decreased heterophil/lymphocyte ratios at day 21. In trial 2, all infected birds had significantly higher mean relative proventriculus weights at 21 days PI and had higher 4-wk mean proventriculus scores as compared with both control groups. In trial 3, birds treated with homogenate and birds treated with both suspect virus and the bacterial isolate had significantly higher proventriculus lesion scores; higher relative weights of proventriculus, gizzard, liver, and heart; lower body weights; and lower relative bursa weights compared with the saline control group. These studies suggest that infectious proventriculitis has a complex etiology involving both viral and bacterial infection.     

B cell differentiation in the bursa of Fabricius and spleen of embryos and chicks immediately after hatching

Flow cytometric analysis and immunohistochemical observation were used to qualitatively and quantitatively clarify the nature of B cell differentiation in the bursa of Fabricius of chick embryos and to determine the timing of antibody class switching in chicken spleens based on positivity of IgM and IgG on and in the cells. In the bursa, the sIgM‐positive cell population formed from the 12^th to 15^th day of embryogenesis. The proportion of sIgM‐high expressing (sIgM^high) cells was lower among bursacytes than splenocytes of hatched chicks, suggesting that the sIgM^high bursacytes are to be released to peripheral sites. The proportion of sIgM^high cells was higher at 0 days old than at any other examined stage of development. Colonization of the spleen by B cells occurred between the 18^th day of embryogenesis and 0 days old. Antibody class switching was thought to start in the spleen between 1 and 2 weeks of age, because IgG‐positive cells were present in the spleen of 2‐week‐old chicks, but not 0‐day‐old or 1‐week‐old chicks.     

Protective immunity against infectious bursal disease virus in chickens in the absence of virus-specific antibodies

The role of cell-mediated immunity (CMI) in pathogenesis of infectious bursal disease virus (IBDV) was investigated. One-day-old specific pathogen-free chickens were treated with 3mg of cyclophosphamide (Cy) per chicken for 4 consecutive days and, 3 weeks later, infected with the IBDV-IM strain. Chickens were examined for: (a) mitogenic response of splenocytes to ConA, as an indicator of T-cell functions in vitro, (b) antibody against IBDV by ELISA, (c) IBDV genome in various tissues by RT-PCR and (d) immunological memory. At the time of IBDV infection, Cy-treated chickens had depleted bursal tissue (an avian primary B-cell lymphoid organ), severely compromised antibody-producing ability, but normal T-cell response to ConA. In primary infection, no detectable antibody against IBDV antigen in Cy-treated, IBDV-infected chickens was observed up to 28 days post-infection (PI), while IBDV genome was detected by RT-PCR in spleen, thymus, liver and blood until 10 days PI. Like intact control chickens infected with IBDV, Cy-treated, IBDV-infected chickens suppressed splenocytes responses to ConA from 5 to 10 days PI, suggesting that intact control as well as Cy-treated chickens responded similarly to IBDV infection in the early phase. Following re-infection with IBDV, no detectable secondary antibody response to IBDV as well as IBDV genome in tissues were observed in Cy-treated chickens, while intact control chickens developed vigorous secondary antibody response. Similar to intact control chickens infected with IBDV, Cy-treated chickens after second infection with IBDV did not suppress splenocyte response to ConA. These results suggested that in the absence of detectable anti-IBDV antibodies, protection of Cy-treated chickens from IBDV infection may occur via immunological memory mediated by CMI. We concluded that under normal conditions, IBDV induces a protective antibody response, however, in the absence of antibody, CMI alone is adequate in protecting birds against virulent IBDV.     

乳酸菌培养物对肉鸡生长性能及免疫功能的影响

试验旨在研究灭活乳酸菌培养物对肉鸡生长性能及免疫功能的影响。选择300只体重相近的健康1日龄AA肉仔鸡,随机分为5组,每组6个重复,每个重复10只鸡,雌、雄各半。其中对照组饲喂基础日粮,抗生素组在基础日粮中添加0.01%金霉素,乳酸菌培养物组分别在基础日粮中添加0.16%乳酸菌培养物L1、L2、L3。试验期42 d,分1~21日龄(前期)和22~42日龄(后期)2个阶段。结果显示,1~21日龄时,乳酸菌培养物L1组肉鸡平均日采食量极显著高于对照组和抗生素组(P<0.01),血清中白介素-2(IL-2)含量显著低于对照组(P<0.05),脾脏指数、胸腺指数、法氏囊指数均显著高于对照组(P<0.05);乳酸菌培养物L2组肉鸡脾脏指数、胸腺指数显著高于对照组(P<0.05);乳酸菌培养物L3组肉鸡平均日增重极显著高于对照组和抗生素组(P<0.01);抗生素组肉鸡血清中γ-干扰素(IFN-γ)含量显著高于乳酸菌培养物组(P<0.05)。22~42日龄时,乳酸菌培养物L1、L2组肉鸡平均日增重极显著高于对照组和抗生素组(P<0.01);乳酸菌培养物L2组肉鸡血清中免疫球蛋白G(IgG)含量显著高于抗生素组(P<0.05),血清新城疫抗体效价及脾脏指数、胸腺指数、法氏囊指数均显著高于对照组(P<0.05);乳酸菌培养物L3组肉鸡血清中免疫球蛋白A(IgA)含量及胸腺指数显著高于对照组(P<0.05)。由此可知,在肉鸡日粮中添加一定量的灭活乳酸菌培养物可在一定程度上提高肉鸡的生长性能、增强其免疫功能,其中,对于提高肉鸡的生长性能,试验前期添加L3效果较好,试验后期添加L1和L2效果较好;对于增强肉鸡的免疫功能,试验前期添加L1效果较好,试验后期添加L2效果较好。     

Effects of Lactic Acid Bacteria Cultures on Growth Performance and Immunity Function of Broilers

This experiment was conducted to study the effects of inactivated lactic acid bacteria cultures on growth performance and immunity function of broilers.A total of 300 one-day-old AA broilers with similar weight were randomly assigned to 5 groups with 6 replicates per group and 10 broilers per replicate (half male and half female).The control group was fed a basal diet;The antibiotic group was fed the basal diet supplemented with 0.01% chlortetracycline;The lactic acid bacteria cultures groups (L1, L2, L3) were fed the basal diets supplemented with 0.16% lactic acid bacteria cultures L1, L2, L3, respectively.The whole experiment period was 42 days, including two phase of days 1 to 21 (starter period) and days 22 to 42 (finisher period).The results showed as follows:From 1 to 21 days of age, ADFI of broilers in lactic acid bacteria cultures group L1 was extremely significant higher than that in control and antibiotic groups (P<0.01), the serum content of IL-2 was significantly lower than that in control group (P<0.05), the indexes of spleen, thymus and bursa of fabricius were significantly higher than that in control group (P<0.05).The indexes of spleen and thymus of broilers in lactic acid bacteria cultures group L2 were significantly higher than that in control group (P<0.05);ADG of broilers in lactic acid bacteria cultures group L3 was extremely significant higher than that in control and antibiotic groups (P<0.01);The serum content of IFN-γ of broilers in antibiotic group was significantly higher than that in lactic acid bacteria cultures groups (P<0.05).From 22 to 42 days of age, ADG of broilers in lactic acid bacteria cultures group L1 and group L2 were extremely significant higher than that in control and antibiotic groups (P<0.01);The serum content of IgG was significantly higher than that in antibiotic group (P<0.05), Newcastle disease antibody titers in serum and the indexes of spleen, thymus and bursa of fabricius of broilers were significantly higher than that in control group (P<0.05);The serum content of IgA and the thymus index of broilers in lactic acid bacteria cultures group L3 were significantly higher than that in control group (P<0.05).Therefore, supplementing inactivated lactic acid bacteria cultures in a diet could improve growth performance and immunity function of broilers to some extent.Among them, adding L3 was better during starter period for improving growth performance of broilers, while add L1 and L2 during finisher period.Adding L1 was better during starter period for improving immunity function of broilers, while add L2 during finisher period.     

酶解谷朊粉对肉仔鸡免疫功能的影响

为了探究酶解谷朊粉对肉仔鸡免疫功能的影响,本试验选用108只肉鸡,随机分为对照组、谷朊粉组和酶解组3个处理组,每组3个重复。对照组饲喂全价基础日粮,谷朊粉组饲喂添有1.2%谷朊粉的日粮,酶解组饲喂添有1.2%谷朊粉酶解液的日粮。结果表明,日粮中添加谷朊粉酶解物后,在21日龄时,酶解组肉仔鸡的胸腺、法氏囊指数较对照组均有显著提高（P〈0.05）,42日龄时,各处理组肉仔鸡的胸腺、法氏囊指数差异均不显著（P〉0.05）,而在脾脏指数方面,无论是21日龄还是42日龄,添加酶解谷朊粉组脾脏指数均呈升高趋势（P〉0.05）。对于整个试验期,胸腺、法氏囊的发育有不同程度的促进作用,其中对早期免疫器官的发育具有显著的改善作用。在肉仔鸡整个生长阶段,日粮中添加谷氨酰胺可提高新城疫HI滴度,还可促进肉鸡外周血T淋巴细胞的分裂增殖,其中以42日龄时酶解组提高最为显著。     

Quantitative measures of disease in broiler breeder chicks of different major histocompatibility complex genotypes after challenge with infectious bursal disease virus

Criteria for evaluating genetic differences in resistance and susceptibility to infectious bursal disease (IBD) within a commercial broiler breeder line of chickens were compared. Line A broiler breeder chickens were challenged with graded doses of Animal and Plant Health Inspection Service (APHIS) strain IBD virus (IBDV) and evaluated at 2 time points, 3 days postinoculation (PI) and 10 days PI. Measures obtained at both time points included bursa to body weight, bursa histology, bursa lymphocyte count, and percentage of T cells in the bursa. Furthermore, viral load in the bursa was determined 3 days PI and anti-IBDV antibody titers, 10 days PI. A dose of 50 50% embryo infective dose caused IBD in about half the line A birds at the 10-day time point, and this dose was chosen for further studies. The data were analyzed for correlation among the various measures. Comparison of the 3-day- and 10-day-PI bursa lymphocyte counts indicated that birds challenged with low doses of virus suffered lymphocyte depletion at the 3-day time point, but many or all (depending on the dose) recovered by the 10-day time point. With a viral dose that caused bursal atrophy in about half the birds by 10 days PI, families segregating for 2 major histocompatibility complex (MHC) haplotypes were compared in terms of resistance to IBD. Results indicated that there was no difference among the 3 MHC genotypes in incidence of IBD by any of the disease measures.     

鸡传染性法氏囊病的病理学研究

人工接种２８日龄非免疫鸡传染性法氏囊病病毒（ＩＢＤＶ）后,对感染鸡的法氏囊、胸腺、脾、盲肠扁桃体、哈德氏腺、肝、肾进行病理组织学检查。感染后４８ｈ,法氏囊淋巴组织最早出现坏死且长久存在。其他淋巴器官的病变出现较迟,程度轻微且恢复较快。ＩＢＤＶ单抗免疫荧光检测,法氏囊及其他淋巴器官中均检测到病毒,接种后１２ｈ法氏囊中即检出病毒,持续时间也最长（攻毒后１２ｄ）,其次是盲肠扁桃体（攻毒后８ｄ）。攻毒１３ｄ以后,上述器官均未检测到病毒。法氏囊粘膜上皮的扫描电镜观察,攻毒后２ｄ,上皮细胞肿胀,微绒毛减少或消失。攻毒后３ｄ,局部上皮细胞坏死、脱落,并向整个粘膜层扩展,攻毒后１０ｄ,上皮层基本修复。     

Detection of infectious bursal disease vaccine viruses in lymphoid tissues after in ovo vaccination of specific-pathogen-free embryos.

Control of infectious bursal disease virus (IBDV) by vaccination is important for poultry production worldwide. Two vaccines, an IBDV immune complex (ICX) vaccine and an IBDV-2512 vaccine, were administered at 100 mean embryo infectious dose to specific-pathogen-free 18-day-old broiler embryos in ovo. At 3, 6, 9, 15, and 21 days post in ovo vaccination (PIOV), bursa, spleen, and thymus tissues were collected and analyzed for virus protein by antigen capture chemiluminescent enzyme-linked immunosorbent assay (ELISA). Chicks were bled and antibody titers were determined by the antibody ELISA. At 21 days PIOV, chickens were challenged with a 1:500 dilution of an antigenic standard IBDV strain. At 28 days PIOV, birds were euthanatized and bursa weight:body weight ratios were determined. Embryos vaccinated with either vaccine exhibited 92% hatchability; however, within 1 wk of hatch, birds vaccinated with IBDV-2512 showed 56% mortality, whereas those given IBDV-ICX had only 3.2% mortality. Both IBDV-ICX and IBDV-2512 vaccines were detected in bursa, spleen, and thymus at day 3 PIOV. A 5-day delay in virus replication was observed with IBDV-ICX vaccine. By day 15 PIOV, the IBDV-ICX was no longer detectable in the bursa and spleen but persisted in the thymus. The IBDV-2512 vaccine persisted in the spleen and thymus on day 15 PIOV. By day 21 PIOV, neither vaccine virus was detected in any lymphoid organ. This assay can be useful in the early detection of vaccine virus in the tissues of chickens vaccinated via the in ovo route. Both vaccines caused bursal atrophy at all times PIOV. The IBDV-2512 caused splenomegaly at day 6 PIOV, whereas splenomegaly was not seen in IBDV-ICX-vaccinated birds until day 9 PIOV. Thymus atrophy was observed in IBDV-2512-vaccinated chicks from day 3 PIOV, whereas this occurred on day 15 PIOV in IBDV-ICX-vaccinated birds. Bursa weight: body weight ratios in IBDV-ICX-vaccinated unchallenged and vaccinated challenged birds were not different (P < 0.05).     

鸡贫血病—法氏囊病联合免疫母鸡后子代雏鸡免疫器官T细胞和抗体生成细胞数量的动态变化

对鸡传染性贫血病（CIA）－传染性法氏囊病（IBD）联合免疫母鸡后的子代雏鸡免疫器官的免疫学化变化进行了研究。结果发现,混合感染CIAV、IBDV雏鸡免疫器官T细胞和IgG,IgM,IgA抗体生成细胞数量在27日龄内明显未免疫对照组、联合免疫组和联合免疫攻毒组,表明感染CIAV、IBDV的雏鸡全身免疫功能显著下降,CAI－IBD联合免疫母鸡后,子代雏鸡T细胞胞和IgG,IgM,IgA抗体生成细胞数量在27日龄内,较未免疫对照组明显增加,表明CIA－IBD联合免疫母鸡可使子代雏鸡免疫器官的免疫功能增强,能抵御强毒攻击。     

谷氨酰胺对肉鸡免疫器官胚后发育的影响

160只1日龄艾维茵肉仔鸡随机分成4组。分别饲喂添加0％、0．2％、0．4％和0．8％谷氨酰胺（Gln）饲粮28d。每周末取鸡24只，每组6只，颈静脉放血致死，取胸腺、法氏囊和脾脏，称重．制作切片．光镜观察，研究基础日粮中添加Gln对肉鸡免疫器官胚后发育的影响。结果显示：（1）添加0．8％Gln组1、4周龄和添加0．4％Gln组2、4周龄胸腺重量显著高于对照组（P〈0．05），添加0．8％Gln组2周龄极显著高于对照组（P〈0．01）；添加0．4％Gln组1、2、4周龄和添加0．8％Gln组4周龄法氏囊重量显著高于对照组（P〈0．05），添加0．8％Gln组1、2周龄极显著高于对照组（P〈0．01）；试验各组脾脏重量均高于对照组。添加0．8％Gln组4周龄显著高于对照组（P〈0．05）。（2）试验组胸腺小叶皮质增厚，淋巴细胞密集，髓质比例减小。胸腺小体减少、减小。试验组法氏囊皱襞内淋巴滤泡增多，皮质增厚．淋巴细胞增多。试验组脾脏脾小结增多、增大；动脉周围淋巴鞘增厚；椭球增多、增大．细胞排列疏松．鞘毛细血管管腔变大．内皮细胞增高。间隙增大。添加0．8％Gln对肉鸡免疫器官发育影响最为明显。结果表明，日粮中添加Gln对肉鸡中枢淋巴器官胚后发育的促进作用优于外周淋巴器官。并有延缓法氏囊退化作用。本试验从组织学角度证明Gln能够促进机体淋巴细胞的增殖分化及免疫器官的胚后发育，进而提高机体的免疫功能。     

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。     

Response of embryonic chicken lymphocytes to in ovo exposure to lymphotropic viruses.

OBJECTIVE: To examine effects of virus exposure on embryonic lymphoid organ structure, apoptosis, and lymphoid cell subpopulations. ANIMALS: Eggs of specific pathogen free (SPF) White Leghorn chickens at embryonation day (ED) 17. PROCEDURES: Eggs were inoculated with 2,000 plaque-forming units (PFU) of serotype 1 herpesvirus (Marek's disease virus [MDV 1]), 2,000 PFU of herpesvirus of turkeys (MDV 3), or 1,000 embryo infectious doses (EID50) of infectious bursal disease virus (IBDV). On post-inoculation days (PID) 3 and 5, lymphoid organ to body weight ratios were determined, and bursa of Fabricius, thymus, and spleen were evaluated for lesions and apoptosis. Proportions of lymphoid cell subpopulations of PID-3 chicken embryos and 7- to 10-day-old chicks were quantitated by flow cytometry. RESULTS: Lymphoid organ weights were similar in virus-free, MDV1, and IBDV groups. Embryos inoculated with 2,000 PFU MDV 3/egg had lower bursal weights than virus-free controls. In a repeated trial, MDV 3 (1,000 PFU to 4,000 PFU) did not reduce bursal weights among groups. Histologic changes were seen in bursae after MDV 1 and IBDV inoculation. Apoptosis was greater in bursae of MDV 1-infected embryos than controls. Lymphoid cell subpopulations were similar among all groups with the exception of CD8+ and IgM+ cells in spleens of IBDV-infected 10-day-old chicks. CONCLUSIONS AND CLINICAL RELEVANCE: Infection with pathogenic strains of MDV 1 and IBDV did not alter lymphocyte subpopulations in embryos or cause complete destruction of lymphoid organs. Changes in lymphoid cell subpopulations exposed as embryos to IBDV were seen only after hatching.