Sequential Pathology of Experimental Aflatoxicosis in Quail and the Effect of Selenium Supplementation in Modifying the Disease Process

Feeding of aflatoxin B1 @ 1 ppm to 2-week old Japanese quail for a period of 8 weeks produced gross and microscopic changes in the liver, skeletal muscles, heart and bursa of Fabricius. These included fatty changes, bile duct hyperplasia and lymphoid aggregation in liver; haemorrhages in thigh, breast muscles and myocardium; mild depletion of lymphocytes, cystic degeneration and fibrous tissue proliferation in bursa of Fabricius. More or less similar lesions were seen in quail chicks fed on aflatoxin with sodium selenite @ 5 ppm but these were of lesser intensity and appeared at later stages of the experiment thereby indicating that supplementation of selenium had some protective action against the toxic effect of aflatoxin B1 in Japanese quail.     

山羊羔淋巴集结的研究

对不同发育时期山羊羔淋巴集结、简称ＰＰ的显微和亚显微结构的观察显示羊ＰＰ的发生和组织学特征与鸟类法氏囊极为相似。同时,羊羔ＰＰ提取液可提高仔兔和仔鸡血清抗体的滴度,促进淋巴组织的发育。实验结果表明山羊ＰＰ是Ｂ淋巴细胞发生的重要部位,山羊ＰＰ中含有类似法氏囊素的物质。     

The effect of polypeptides from the thymus, bone marrow and bursa of Fabricius on the immunogenesis and hemostasis in neonatally thymectomized and antenatally bursectomized chickens

The effect of polypeptides from the thymus, bone marrow and bursa of Fabricius on immunogenesis and hemostasis was investigated in neonatally thymectomized and antenatally bursectomized chickens. It has been established that polypeptide factors from the bursa of Fabricius have the most pronounced effect on the immunity and hemostasis.     

Nuclei of lymphocytes of the T- and B-cell lines during normal embryogenesis and after treatment with hydrocortisone (morphometric and probabilistic-statistical parameters)

Lymphoid cells of the thymus and of the Fabricius bursa have been studied in 18-day-old chick embryos, normal and after injection of hydrocortisone on the 11th day of embryogenesis. By means of optical-structural computer analysis, the complex of morphometric and probability-statistic parameters of the nuclei in the lymphocytes are estimated: area of the nuclei, optical density of chromatin, asymmetry coefficient and variance. Normal T-lymphocytes possess less density of the nuclei, greater optical density of chromatin, greater values of negative asymmetry. The complex of these parameters can be used for identification of visually similar lymphoid cells of T- and B-lines. Under hydrocortisone effect structural changes of the nuclei in the thymus and Fabricius bursa lymphocytes of the chick embryo are uniform: increase in the area of the nuclei, decrease in optical density of chromatin, the asymmetry coefficient becomes positive.     

Immunomodulatory roles and functional analysis of pre-B lymphocyte DT40 cells with the bursal-derived BSP-II treatment

The bursa of Fabricius, the acknowledged central humoral immune organ, is vital to B cell differentiation. However, the regulatory function of the bursal-derived peptide on avian B cell proliferation has not been reported. BSP-II is a recently reported bursal-derived bioactive peptide. In this paper, 75 days-old chicks were twice subcutaneously immunized with BSP-II and inactivated avian influenza virus (AIV, H(9)N(2) strain). It was proved that BSP-II induced a strongly AIV-specific HI antibody production in the immunized chicks. Also, BSP-II could enhance avian pre-B lymphocyte DT40 cell viability. To investigate the global patterns of gene expression in DT40 cells after BSP-II treatment, gene microarray was carried out. It was identified that the differentially expressed genes were involved in various pathways, of which six pathways were associated with signaling transductions, including ErbB signaling, MAPK signaling, Toll-like receptor signaling, Notch signaling, mTOR signaling, and Wnt signaling. Finally, RT-qPCR was used to confirm the microarray expression data. These results indicated the molecular basis of pre-B lymphocyte viability with BSP-II treatment, which provided a potential mechanism of the bursa of Fabricius on pre-B lymphocyte viability, differentiation, and development. These results are valid for the mechanism of the bursa of Fabricius on B lymphocytes development.     

Regulating properties of peptides of the thymus and bursa of Fabricius in immunodepression in birds

The intensity of nucleic acids and protein synthesis in the cells of the thymus and the bursa of Fabricius was studied in chickens against the background of an immunodepression induced by administration of hydrocortisone and cyclophosphamide. It was found out that hydrocortisone causes in chicken a marked lowering of the intensity of inclusion of 3H-thymidine, 3H-uridine and 14C-glycine in thymic cells, and cyclophosphamide--in the cells of the bursa of Fabricius. Under the conditions of selective immunodepression the preparations on the basis of the peptides of the thymus (thymalin) and of the bursa of Fabricius (bursilin) regulate the processes of nucleic acids and protein synthesis chiefly in the cells of organs which produce them.     

The effects of trichothecene toxins on the Bursa of Fabricius in day-old chicks.

The effects of T-2 toxin, Fusarenon X (FX), and Nivalenol (NV) on the bursa of Fabricius in the day-old chick were examined. After injections of 5 mg/kg of the mycotoxins into the residual yolk sac, cellular injury was limited at first to the smaller epithelial cells with coarse microvilli, which were located in the central portion of the follicle-associated epithelium. Subsequently necrosis spread out to the periphery. Degeneration and necrosis followed in the lymphoid cells in the lymphoid follicles. The other epithelial components in the follicle were relatively resistant to the mycotoxins. Both FX and NV were less potent than T-2 toxin, although the effects on the bursa of Fabricius were essentially the same. These findings suggest that the follicle-associated epithelium is clearly distinguished from other epithelial components in the bursa of Fabricius in day-old chicks.     

Ontogeny of lymphocytes expressing J chain in chickens

The ontogeny of chicken lymphocytes expressing J chain (LEJ) was investigated in the embryonic bursa of Fabricius, the spleen, and the thymus. Simultaneous appearance of LEJ was detected in the bursa and spleen on Day 14 of incubation. These cells were detected later in the thymus. The LEJ were found to increase rapidly in the spleen from the 19th to 20th incubation day. In adult chickens, the highest percentage of LEJ was also found in the spleen. These cells were seen in the thymus at a lower frequency. Intermediate numbers were found in bursal and peripheral blood lymphocytes. The frequencies of the LEJ were similar to those of lymphocytes positive for cytoplasmic immunoglobulins (Ig) IgA and IgM, but were not related to the number of lymphocytes expressing surface Ig. It is possible to consider that the suitable site for LEJ is the spleen, on the basis of the rapid increase in the number of LEJ just before hatching and from the fact that the highest value is found in adult chickens. Furthermore, LEJ may participate in secretion of IgA or IgM but not be associated with the expression of surface Ig.     

Investigation of the site of precursors for IgA-producing cells in the chicken intestine

Bursectomized chicks received lymphocyte single cell suspensions harvested from the bursa of Fabricius (BF), ileal lymphoid aggregate (ILA), caecal tonsils (CT), spleen and peripheral blood. Four days after cell transfer, repopulation of the duodenal and CT lamina propria in age-matched recipient bursectomized chickens with IgA-secreting plasma cells was determined. The results indicate the highest level of reconstitution with cells derived from BF, but substantial numbers of IgA-secreting plasma cells were also observed in a number of birds that received lymphocytes originating from the ILA and CT.     

原位杂交检测人工感染鸭体内鸭瘟病毒的复制

鸭瘟(Duck plague,DP)是由鸭瘟病毒(Duck plague virus,DPV)引起的鸭、鹅和天鹅的一种急性败血性传染病,发病率和死亡率甚高,是养鸭业的一大危害[1-2].     

Selective expression of RAG-2 in chicken B cells undergoing immunoglobulin gene conversion

Chickens create their immunoglobulin (Ig) repertoires during B cell development in the bursa of Fabricius by intrachromosomal gene conversion. Recent evidence has suggested that Ig gene conversion may involve cis-acting DNA elements related to those involved in V(D)J recombination. Therefore, we have examined the potential role of the V(D)J recombination activating genes, RAG-1 and RAG-2, in regulating chicken Ig gene conversion. In contrast to the coexpression of RAG-1 and RAG-2 observed in mammalian B cells that undergo V(D)J recombination, chicken B cells isolated from the bursa of Fabricius express high levels of the RAG-2 mRNA but do not express RAG-1 mRNA. The developmental and phenotypic characteristics of the bursal lymphocytes and chicken B cell lines that express RAG-2 mRNA demonstrate that selective RAG-2 expression occurs specifically in B cells undergoing Ig diversification by gene conversion. These data suggest that RAG-2 plays a fundamental role in Ig-specific gene conversion.     

Localization of vasoactive intestinal peptide binding sites in the thymus and bursa of Fabricius of the chick

The purpose of this study was to determine the distribution of VIP binding sites in the thymus and bursa of Fabricius using receptor binding and autoradiographic techniques. Biochemical characterization of 125I-VIP binding sites determined two classes of specific binding sites in both tissues. The dissociation constants determined in the thymus were 1.12 nM and 88.5 nM, and in the bursa were 0.459 nM and 70.8 nM. Autoradiographic localization of 125I-VIP binding sites within the thymus demonstrated specific binding associated with the medullary region of the thymic lobule and the blood vessels in the interlobular and trabecular areas. Within the bursa of Fabricius, high densities of silver grains corresponded with vascular elements in the interfollicular regions, the epithelial border of the plicae, the muscular layer surrounding the organ, and the diffusely infiltrated area near the burso-cloacal duct.     

Effects of Dietary Selenium on Selenoprotein W Gene Expression in the Chicken Immune Organs

Selenoprotein W (SelW) is expressed in the immune systems of mammals. However, its pattern of expression in the immune organs of birds is still unclear. To investigate the distribution of SelW and effects of dietary Se levels on the SelW mRNA expression in the immune organs of birds, 1-day-old male chickens were fed either a commercial diet or an Se-supplemented diet containing 0.601, 1.058, 1.514, or 2.427?mg Se per kilogram, and 1.0, 2.0, 3.0 or 5.0?mg sodium selenite per kilogram for 90?days. The immune organs (spleen, thymus, and bursa of Fabricius) were collected and examined for Se content and SelW mRNA levels. The mRNA expression of SelW was detected in all the tissues. Although Se content was the highest in the spleen, the remarkable stability of the SelW mRNA level was observed in this organ during different times of dietary Se supplementation. Se-supplemented diet can make the SelW expression levels higher within a certain range in thymus and bursa of Fabricius. The present study demonstrates that SelW is widely expressed in immune organs of birds and that Se-supplementation of the feed increases SelW expression in the thymus and the bursa of Fabricius.     

The latex particle adherence (LPA) assay for detection of leukocytes with adhesive surface properties.

A new, simple, and rapid in vitro assay has been developed for identification of adherent and nonadherent leukocytes. The assay is based on adherence of latex (polystyrene) particles to the cell surface. Using the latex particle adherence (LPA) assay, the percentage of adhesive leukocytes has been determined in human peripheral blood mononuclear preparations and in the lymph nodes, thymus, bursa of Fabricius, spleen, and bone marrow of mouse, chicken, and rat origin. The highest proportion of LPA-positive cells was found in peritoneal exudate, bone marrow, and spleen, the lowest proportion, in thymus and bursa of Fabricius. LPA-Positive cells in human peripheral blood mononuclear preparations were identified as surface immunoglobulin-positive lymphocytes nonrosetting with sheep red blood cells. LPA-Positive cells in peritoneal exudate were identified as macrophages. Incubation of leukocyte suspensions on polystyrene petri dishes or nylon wool columns reduces substantially the percentage of LPA-positive cells in the nonadherent fraction. The LPA assay seems to be a method of choice for establishing the relationship between adhesiveness of the cell surface and other cell membrane markers on a single-cell level.     

The Cell Cycle Arrest and Apoptosis of Bursa of Fabricius Induced by Low Selenium in Chickens

The purpose of this 42-day study was to investigate the effects of low selenium (Se) on immune function by determining cell cycle and apoptosis of bursa of Fabricius. One hundred twenty 1-day-old avian broilers were randomly assigned to two groups of 60 each and were fed on a low Se diet (0.0342 mg/kg Se) or a control diet (0.2 mg/kg Se), respectively. The relative weight of bursa was significantly decreased in low Se group from 28 days of age in time-dependent manner when compared with that of control group. Cell cycle analysis by flow cytometry showed that low Se caused an increase in G₀G₁ phase cells that corresponded to a decrease in S phase cells in bursa of Fabricius. Ultrastructurally, mitochondria injury and increased apoptotic cells with condensed nuclei were observed. Low Se increased the percentage of Annexin V-positive cells, as measured by flow cytometry, in comparison with that of control group. These data suggested that low Se diet restrained the development of bursa of Fabricius by cell cycle arrest and apoptosis.     

Survival and function of bursa-derived cells in bursectomized chickens

Chicken given heterologous antibodies to μ chains as embryos and again following bursectomy at hatching were rendered permanently agammaglobulinemic, whereas treatment with anti-μ alone resulted in transient hypogammaglobulinemia. These and other observations indicate that sites other than the bursa of Fabricius are unable to serve as sources of immunoglobulin-producing cells. Agammaglobulinemia did not develop in birds bursectomized at 1, 14, or 35 days after hatch during an observation period of 21–125 wk. Some bursectomized birds developed 10 × normal IgM levels but were very deficient in IgG; this pattern persisted throughout life. B lymphocytes, identified by surface immunoglobulins in high density, were permanently deficient in bursectomized animals despite development of hypergammaglobulinemia and high levels of antibodies to ferritin following hyperimmunization. In experiments employing embryonic bursectomy, the level of the circulating pool of B lymphocytes was shown to be dependent upon the time allowed for the bursa to function before removal.     

Sequential expression of germ line genes in development of immunoglobulin class diversity.

Differentiation of B cells occurs in two discontinuous stages. Primary differentiation of stem cells to B lymphocytes in birds occurs exclusively in the lymphoepithelial bursa of Fabricius; the fetal liver may serve this function in mammals. In chickens both the size of the B-lymphocyte pool and the generation of precursors for cells secreting different immunoglobulin classes is controlled by the bursa. The latter process involves the sequential expression of genes coding for heavy chain constant regions in the order mu, gamma, alpha. The second stage of B-cell differentiation is antigen-driven, and involves proliferation and maturation of B lymphocytes to plasma cells. Ontogenetic development of different classes of B lymphocytes in mammals is orderly, independent of exogenous antigens, and occurs in the sequence mu, gamma, alpha. A developmental switch in expression of Ch genes, beginning with mu, has been experimentally verified. We favor the hypothesis that generation of class diversity of B lymphocytes occurs during the antigen-independent first stage of differentiation, and that the genetic switch in Ch gene expression follows the sequence mu leads to gamma leads to alpha, but evidence of these points remains inconclusive.     

Biochemical characterization of the progesterone receptor in the chick bursa of Fabricius

In a previous work we demonstrated estrogen-inducible progesterone binding sites in the bursa of Fabricius. In the present study these were characterized and compared to the progesterone receptor (PR) in the chick oviduct. When the size of the binding sites was analyzed with sucrose gradient centrifugation, 2 peaks of bound progesterone were obtained. The sedimentation coefficients of the peaks were 8-9 S and 3-4 S. In size exclusion HPLC only 1 peak was seen with a size corresponding to the 8-9 S in the sucrose gradient. The Stokes radius was 7.7 nm. When the ionic strength was elevated or CaCl2 was added, smaller steroid binding forms were detected. The sizes of these progesterone binding molecules at low and high ionic strength and in the presence of CaCl2 were equal in bursa and oviduct when analyzed with HPLC. The Stokes radii of these forms were 5.6 nm in high salt and 2.1 nm with CaCl2. The steroid binding components in the bursa cytosol eluated as 2 peaks from the DEAE column with KCl gradient. The peaks corresponded to the so-called A and B components in the chick oviduct. In the presence of molybdate, bound progesterone eluated as one peak from DEAE in both oviduct and bursa. The progesterone binding capacity was shown to be heat labile with equal half-lives in the bursa and the oviduct. Progesterone and ORG 2058 had a high affinity for the binding site and their binding was specific for progestins. It is concluded that the estrogen-inducible progesterone binding site in the bursa of Fabricius resembles the oviductal progesterone receptor in structural and binding properties.     

Intraepithelial lymphocytes in the excurrent ducts of the testis of the domestic fowl (Gallus domesticus).

Cells considered to be lymphocytes are reported in the epithelial lining of the excurrent ducts of the testis of normal and vasoligated domestic fowl. They resemble those already reported in the rat and monkey epididymal epithelium, the human intestinal mucosa, and in the bursa of Fabricius. The cytoplasm is usually less dense than that of adjacent epithelial cells, and contains only a few organelles. The nucleus is highly heterochromatic and with no definite nucleolus. Cytoplasmic processes are found to extend from the cell in between epithelial cells. The possible role of these cells in the reproductive tract of the cockerel is discussed.     

Pathological changes in chickens inoculated with reticuloendotheliosis-virus-contaminated Marek's disease vaccine.

A disease characterized by delayed growth, anemia, abnormal feathers, and leg paralysis occurred among chickens inoculated with Marek's disease vaccine over a period from spring to fall in 1974. These chickens were recognized among flocks inoculated with the vaccine produced by two vaccine makers. The affected ones were examined pathologically. Gross examination revealed a slight enlargement of peripheral nerves and atrophy of the spleen, thymus, and bursa of Fabricius. Histopathologically, the peripheral nerves had a mild cell infiltration of lymphoid and plasma cells, edema, degeneration of nerve fibers with Schwann's cell proliferation. Perivascular cuffings consisting mainly of lymphoid cells were seen in the brain and spinal cord. Atrophic changes displayed by prominent reduction of lymphocytes were recognized in the spleen, thymus, and bursa of Fabricius. Etiological examination suggested that most of the chickens examined might have been infected with reticuloendotheliosis virus and not with Marek's disease virus. The pathological changes observed in the peripheral nerves and central nervous system, however, were not distinguishable from those of Marek's disease.