Bursal Follicles Research Articles

Characterization and ontogeny of a novel lymphoid follicle inducer cell during development of the bursa of Fabricius.

The avian bursa of Fabricius (BF) is a primary lymphoid organ, where B-cell development occurs within bursal follicles of epithelial origin. During embryogenesis the epithelial anlage of the BF emerges as a diverticulum of the cloaca surrounded by undifferentiated tail bud mesenchyme. While it is believed that the epithelial-mesenchymal BF primordium provides a selective microenvironment for developing B cells, the initial events inducing lymphoid follicle formation are not fully elucidated. Using wild type and CSF1R-eGFP transgenic chick embryos, we find that separate B cell, macrophage and dendritic cell precursors enter the BF mesenchyme, migrate to the surfaceepithelium, and colonize the lymphoid follicle buds. Detailed immunocytochemical characterization revealed a novel EIV-E12+ blood-borne cell type, colonizing the surface epithelium of the BF rudiment before the entry of myeloid and lymphoid lineages and the appearance of this cell type coincides with the onset of follicle bud formation. Chick-duck chimeras and chick-quail tissue recombination experiments suggest that EIV-E12+ cells represent a transient lymphoid inducer cell population. They are not dendritic or B cells precursors, and they are capable of follicle bud induction in both dendritic cell- and B cell-depleted bursae.

Early-life immunomodulation by carvacrol delivered in ovo in broiler chickens

In the first 2 wk after hatching, broiler chickens are vulnerable to enteric pathogens due to underdeveloped gastrointestinal and immune systems. Carvacrol has been reported to improve digestive and immune functions. This study aimed to optimize immune development of broiler chickens by delivering carvacrol in ovo. Effects of 2 in ovo treatments delivered at embryonic day (E)17.5 (saline or carvacrol) were evaluated at 3 stages (E19.5, hatch, and d 14 posthatch). Hatchability, performance parameters, lymphoid organ and yolk sac weights were determined. Histomorphology assessment was performed for jejunal samples at hatch and bursa of Fabricius samples at hatch and d 14. Gene expression of immune-relevant genes was determined for jejunal, bursal, and yolk sac samples over time. At hatch, BW was 0.85% lower (P = 0.02) after in ovo carvacrol delivery compared to the controls. Interactions between in ovo treatment and age were found for gene expression. At hatch, carvacrol treatment resulted in lower expression of proinflammatory cytokines IL-8 and IFN-γ in the yolk sac compared to the controls (P = 0.05 and < .001, respectively) suggesting a potential role for carvacrol-mediated immune modulation. At d 14, carvacrol treatment led to lower expression of proinflammatory cytokine IL-6 in the bursa compared to the controls (P = 0.002). In ovo carvacrol delivery led to bursal histomorphometric changes, including a larger cortex in the bursal follicles (P = 0.03), and a higher cortex/medulla ratio (P = 0.04) compared to the controls, indicating increased B-cell stimulation and maturation. Main effects were found for carvacrol treatment in the jejunum, with overall higher expression of proinflammatory mediators IL-1β and NF-κB, and anti-inflammatory IL-10 compared to the controls (P = 0.04, 0.02, and 0.02 respectively) from E19.5 to d 14. Age-related main effects showed various alterations in expression dynamics of immune-related genes across all tissues over time. Our findings suggest changes in immune parameters occur as the chicken develops, but these mostly do not interact with in ovo carvacrol treatment. In ovo carvacrol treatment alters immune activity of broiler chickens independent of age.

Protective effects of rabbit sacculus-derived antimicrobial peptides on SPF chicken against infection with very virulent infectious bursal disease virus

Previous studies here have demonstrated that the rabbit sacculus rotundus-derived antimicrobial peptides (RSRP) could alter the intestinal mucosal immune responses in specific-pathogen-free (SPF) chickens, however, the protective effects of RSRP on chickens against infection remain questionable. In the present study, eighty SPF chickens were randomly divided into five groups and challenged with very virulent infectious bursal disease virus (vvIBDV) to determine the protective effects and its underlying mechanism of RSRP. Histopathology examination found that vvIBDV-infection caused severe damage in the bursa of Fabricius, especially the bursal lymphoid follicles underwent severe necrosis, depletion, hemorrhage, and edema. Unexpectedly, RSRP intervention significantly reduced the necrosis and depletion of lymphoid follicles in the vvIBDV-infected chickens. Moreover, RSRP treatment significantly decreased the expression of Bax (P<0.01) as well as remarkably promoted the expression of Bcl-2 (P<0.01), concomitantly alleviated the excessive apoptosis in the immune organs such as the bursa of Fabricius during vvIBDV infection. Notably, consistent with our previous reports that increased mast cell activation and degranulation in the bursa after vvIBDV infection, RSRP administration considerably reduced the mast cell density and the expression of tryptase, a marker for activated mast cells. Collectively, the present study indicates that rabbit sacculus rotundus-derived antimicrobial peptides could effectively protect the major immune organs including the bursa of Fabricius from the damage caused by vvIBDV infection, which provides the possibility and a promising perspective for the future application of antimicrobial peptides for poultry production.

Analysis of the Development of B-Cell Precursors in Day Three Incubated Chicken Embryos

Background: In mammals, birds, and amphibians, the B lineage of lymphoid cells first arise during embryogenesis and are distinguished by their capacity to produce immunoglobulin. For the purpose of researching the development of the B-cell repertoire and the development of self-tolerance, these early B-cell precursors are of utmost importance. The genetic and/or microenvironmental variables that control the beginning of immunoglobulin synthesis in embryonic haemopoietic cells are, however, poorly understood. Purpose: The ontogeny of B-cell precursors in chicken embryos from day three of incubation was examined in this work. Research methods: The terms "ontogeny, B-cell, precursors, chicken embryos, incubation" were used in a thorough literature search in the PubMed, NCBI, and Google Scholar databases. After all articles were picked based on the inclusion and exclusion criteria, 38 papers that satisfied the criteria for inclusion were collected. Result: The study's findings show that clglarge basophilic hemopoietic stem cells and cIg+ small lymphoid B-cell precursors are two types of migrant cells that appear to enter the embryonic bursa of Fabricius. Hence, B lymphopoiesis does not only take place in the bursa of Fabricius in the avian embryo. Although the yolk sac and the hemopoietic tissues around the dorsal aorta are strong candidates, the identity of the extra-bursal location remains unknown. Conclusion: Hence, general haemopoietic organs may serve as the initial site of B lymphopoiesis in both birds and mammals. Only later in the course of avian development do the bursal follicles become accessible and take over.

Morphological, molecular, and pathological studies on Prosthogonimus cuneatus in Indian peacocks (Pavo cristatus)

ABSTRACT This report provides the first record of Prosthogonimus cuneatus infection in Indian peafowl. Chickens, turkeys, geese, ducks, and other pet birds are recognized as direct hosts of Prosthogonimus species; however, P. cuneatus has not been reported to infect peafowl globally. Here, we identify the trematode present in the bursa of the peafowl by both morphological and molecular methods, in addition to the changes in the bursal tissue induced by the parasite, using histopathology. After a necropsy examination, the trematodes were found in the bursa of Fabricius in three peafowl. Morphological and molecular approaches based on taxonomic characteristics and the sequencing of the trematode-specific internal transcribed spacer (ITS) gene, respectively, were employed for trematode identification. The consensus sequences were compared to P. cuneatus reference sequences from GenBank. In order to assess the pathology caused by the parasite, a histological study of the bursa was also performed. Trematodes were confirmed as P. cuneatus based on morphology and DNA sequencing. Further, histopathological evaluation revealed mild lymphoid depletion of the bursal follicles in both the cortex and medulla with associated thinning of the bursal follicular lining epithelium. Indian peafowl can act as a natural host of P. cuneatus. This study provides a detailed pathological and molecular analysis of P. cuneatus affecting Indian peafowl.

Effect of Intermediate Plus Vaccine and vvIBDV on Bursa Secretory Cells and Their Glycoprotein Production.

There are two types of secretory cells in the chicken bursa of Fabricius (BF): (a) interfollicular epithelial cells (IFE), and (b) bursal secretory dendritic cells (BSDC) in the medulla of bursal follicles. Both cells produce secretory granules, and the cells are highly susceptible to IBDV vaccination and infection. Before and during embryonic follicular bud formation, an electron-dense, scarlet-acid fuchsin positive substance emerges in the bursal lumen, the role of which is unknown. In IFE cells, IBDV infection may induce rapid granular discharge, and in several cells, peculiar granule formation, which suggests that the glycosylation of protein is injured in the Golgi complex. In control birds, the discharged BSDC granules appear in membrane-bound and subsequently solubilized, fine-flocculated forms. The solubilized, fine-flocculated substance is Movat-positive and can be a component of the medullary microenvironment, which prevents the medullary B lymphocytes from nascent apoptosis. Vaccination interferes with the solubilization of the membrane-bound substance, resulting in: (i) aggregation of a secreted substance around the BSDC, and (ii) solid lumps in the depleted medulla. The non-solubilized substance is possibly not "available" for B lymphocytes, resulting in apoptosis and immunosuppression. In IBDV infection, one part of the Movat-positive Mals fuse together to form a medullary, gp-containing "cyst". The other part of Mals migrate into the cortex, recruiting granulocytes and initiating inflammation. During recovery the Movat-positive substance appears as solid, extracellular lumps between the cells of FAE and Mals. Possibly the Mals and Movat-positive extracellular lumps glide into the bursal lumen via FAE to eliminate cell detritus from the medulla.

EFFECT OF DRINKING IONIZED WATER ON HISTOLOGICAL CHANGES, BACTERIA COUNT, AND SOME HEMATOLOGICAL PARAMETERS OF JAPANESE QUAIL

This experiment was conducted to study the effect of drinking ionized water on histological changes, bacteria count, and some hematological parameters of Japanese quail. A total of 200-42-day-old Japanese quails were divided into five treatments. The birds of each treatment were divided into four replicates. The pH level of drinking water of the first treatment was 7, whereas the pH levels of drinking water of other treatments were 8, 9, 6, and 5 respectively. The results showed that villi height, crypt depth, and mucous layer thickness of the duodenum were increased (P&lt;0.05) in T4 and T5. The normal histological structure was observed in the microscopic section of the liver of the treated group. The pH 7 of drinking water led to the depletion of the follicles and an increase in the interfollicular space of birds (Fig4). In addition, there was hemorrhage among the bursal follicles in the bursa of birds that received pH8 drinking water (Fig5). The pH5 of drinking water showed mild lymphoid depletion in the section of the bird bursa (Fig6). Also, the pH9 of drinking water showed large vacuoles in the epithelial layer which support the lymphoid follicles in the section of the bursa (Fig 7). There were thickening and degeneration changes in the capsule with lymphocyte aggregation in birds that received pH9 of drinking water (Fig8). The levels of pH of drinking water affect WBC, Hb, and PCV. Drinking acidic ionized water increased the number of Lactobacilli bacteria and decreased the number of Coliform bacteria. Conclusion: The pH 8 and 5 of drinking water had a positive role in the histological changes, bacterial count, and some hematological parameters of Japanese quail.

Immune Response and Histological Changes in Broilers Chickens Vaccinated with Mycoplasma gallisepticum Vaccines.

Mycoplasma is unique among prokaryotes because of its small size, small genomes, and complete lack of cell walls, which makes them cell wall-less prokaryotes. This study aimed to evaluate the effect of vaccinating one-day-old chicks with inactivated and live vaccines (CRDF) of Mycoplasma gallisepticum (MG) on their humoral immune response and immune organs. The Enzyme-Linked Immunosorbent Assay was used to measure Ab titers and investigate histopathological changes. A total of 130 one-day-old broiler chicks were randomly divided into four groups of 30. The groups were treated as follows: G1 included the chicks vaccinated with live F-strain MG vaccine (on eye drop of 0.03ml/dose), G2 included the chicks vaccinated with inactivated MG (0.3 ml s.c) vaccine, G3 included the chicks vaccinated with inactivated and live MG vaccines, and G4 was considered the control group, in which the chicks were not vaccinated. Blood samples were collected on days 21 and 35 of the chick's life to measure the titers of specific antibodies. On day 35, the chicks were dissected, and the bursa of Fabricius, as well as the spleen, were removed for histological evaluations. On day 21, the results showed a significant difference (P≤0.05) between all vaccinated groups in Ab titers, compared to G4, with the highest mean in G3, followed by G2 and G1, in descending order. On day 35, there was a significant difference (P≤0.05) between G3 and other vaccinated groups (G2 and G1), as well as G4. In addition, there was a significant increase in all vaccinated groups on day 35, compared to day 21. In G1, histopathological examination results showed a moderate lymphocytic hyperplasia bursal follicle. In G2, varying degrees of lymphoproliferative were observed in the major bursal follicle, and in G3, a marked lymphocytic hyperplasia bursal follicle was observed. In G4, on the other hand, no obvious histopathological findings were recorded. The results of the spleen histopathological evaluation showed various degrees of lymphoproliferative and moderate neutrophilic infiltrate in the red pulp in G1, and mild sinus congestion with scattered lymphocytes was recorded in the lumen in G2. In the spleen of the chicks in G3, reactive lymphoid hyperplasia was observed. In contrast to the groups mentioned above, in G4, the spleen structure showed a typical structure. It was concluded that the chicks vaccinated with inactivated and live MG vaccines experienced increased production of Ab titers and the immune stimulation of immune organs.

Modulation of Immunity, Antioxidant Status, Performance, Blood Hematology, and Intestinal Histomorphometry in Response to Dietary Inclusion of Origanum majorana in Domestic Pigeons’ Diet

This experiment was conducted to evaluate the effect of adding Origanum majorana (OM) powder to domestic pigeon diets on growth performance, feeding and drinking behaviour, blood hematology, blood biochemical parameters, blood inflammatory and oxidative markers, carcass characteristics, the weights of lymphoid organs, and and intestinal cecal, and bursa of Fabricius histology. A random distribution of fifty-four unsexed pigeon squabs (30 days old, average body weight; 321 g ± 7.5) into three groups was done. The first group was fed the grower basal diet without adding OM powder, while OM powder was added at levels of 0.5 and 1% to the basal diets of the second and third groups, respectively. The changes in growth performance parameters and feeding and drinking behavior under OM powder's effect were insignificant. However, the lymphoid organs (spleen and thymus) significantly increased in weight (p < 0.05) in the OM-fed groups. Moreover, blood examination showed positive responses to OM powder in terms of blood cell counts (RBCs andWBCs), and the values of hemoglobin, hematocrit, mean corpuscular volume, lymphocyte numbers, levels of globulin, and glutathione peroxidase enzyme were significantly increased. The numbers of heterophils, the ratio of heterophil to lymphocyte, malondialdehyde levels were reduced (p < 0.05). Histomorphometry examination revealed increases in intestinal villi height, cecal thickness, and bursal follicle area and number. These results indicated that adding OM powder to the pigeon diet may improve their immunity, increase their antioxidant status, and correct some hematological disorders.

Glycoprotein Production by Bursal Secretory Dendritic Cells in Normal, Vaccinated, and Infectious Bursal Disease Virus (IBDV)-Infected Chickens.

The aim of this study is to follow the gp production in IBDV-vaccinated and challenged birds. The progress of IBDV infection was monitored using anti-VP2 immunocytochemistry, light and transmission electron microscopy. In the medulla of the bursal follicle, the Movat pentachrome staining discovered an extracellular glycoprotein (gp) produced by bursal secretory dendritic cells (BSDCs). The secretory granules of BSDCs either discharge resulting in extracellular gp or fuse together forming intracellular corpuscles. The double fate of granules suggests a dual function of BSDCs: (a.) For the discharged granules, gp contributes to the medullary microenvironment (ME). (b.) The intracellular corpuscles may be the sign of BSDC transformation to a macrophage-like cell (Mal). Infectious bursal disease virus (IBDV) infection accelerates the BSDC transformation to Mal. The decreased number of BSDCs is feedback for the precursor cells of BSDCs lodging in the cortico-medullary epithelial arches (CMEA), where they proliferate. Opening the CMEA, the precursor cells enter the medulla, and differentiate to immature BSDCs. The virus uptake in the corpuscles prevents the granular discharge resulting in the absence of gp and alteration in ME. In vaccine-take birds, the mitotic rate of BSDC precursor cells cannot restore the precursor pool; therefore, in the case of IBDV challenge, the number of newly formed BSDCs is too low for outbreak of clinical disease. The BSDCs, as a primary target of IBDV, may contribute to the long-lasting immunosuppressive status of IBDV-infected chickens.

The morphology and differentiation of stromal cells in the cortex of follicles in the bursa of Fabricius of the chicken.

Mesenchymal reticular cells (MRCs) form a supporting system in the cortex of the bursal follicle. The stellate-shaped MRCs exhibit a low electron density, which is helpful for their identification. A remarkable feature of MRC is the formation of multiple blebs in the nuclear envelope. The large, irregularly shaped blebs-which are perinuclear spaces-may be detached from the nuclear membrane, creating a sac-like granular endoplasmic reticulum (GER). Inside the bleb, membrane-bound bodies originate from cytoplasmic impressions. The cytoplasm contains a few round mitochondria, in which the internal membranes form either ovoid vesicles or the entire internal structure is indistinct. These mitochondria may be associated with the blebs. The classical Golgi complex with cis and trans faces cannot be recognized, but the accumulation of very small vesicles occurs around two or three stacked flat cisterns. The MRC forms a continuous layer along the corticomedullary basal lamina (CMBL), and during cell migration between the cortex and medulla, it may contribute to the temporary closure of the gap in the CMBL. At the outer surface of the cortex, transitory cells between the MRC and fibrocytes of the interfollicular connective tissue are present, and both cells can produce GER by blebbing. This finding suggests that MRCs and fibrocytes may have a common origin. The other stromal cell is the macrophage (Ma), which may fuse together to form multinucleated giant cells. The definition of histological classification of the third type of stromal cell is questionable, but certain morphological features may be referred to as progenitors of MRCs.

The bursal secretory dendritic cell (BSDC) and the enigmatic chB6+ macrophage-like cell (Mal)

The bursal secretory dendritic cell (BSDC) was discovered more than 40 yr ago. It is a highly polarized, granulated cell, locating in the medulla of bursal follicle. The cytoplasmic granules either discharge or fuse together forming large, irregular-shaped, dense bodies. Formation of the dense bodies could be the first sign of BSDC transformation to macrophage-like cell (Mal) which is the result of terminal maturation of BSDC. The BSDC is non-phagocytic, unlike Mal. The discharged substance may be attached to the cell membrane (membrane-bound form) and after detaching, appears as a flocculated substance in the extracellular space of medulla. Movat pentachrome staining shows, that this substance is a glycoprotein (gp), which may be contributed to the microenvironment of the medulla. Medullary lymphocytes are floating in the gp. Precursors of the BSDC locate in the corticomedullary epithelial arches, which operate under the effect of Notch/Serrate signaling. The Notch signaling determines the fate of lymphoblast-like precursor cells and inhibits the appearance of immunoglobulin heavy chain. In the arches, the precursor cells proliferate and entering the medulla differentiate. The dense bodies pack the virus particles, which prevents the granular discharge, resulting in disappearance of extracellular gp, but gp emerges inside the virus containing Mal. In infected birds, the Mal contains either apoptotic cells or virus particles. If vaccination or infectious bursal disease virus (IBDV) infection use up the BSDC precursors, the recovery of follicle is critical.

Characterization and functional properties of a novel monoclonal antibody which identifies a B cell subpopulation in bursa of Fabricius

The bursa of Fabricius (BF) plays a central role in the development of B lymphocytes in birds. During embryonic development the BF primordium is colonized by myeloid and lymphoid prebursal stem cells to form the follicle buds, which ultimately develop into lymphoid follicles with a central medullary and an outer cortical region. Lympho-myeloid differentiation within the medulla is fundamental to normal B cell development. In contrast, the complexity of the cellular composition of the follicular cortex and its role in B cell differentiation has only recently begun to be studied. As an effort to characterize the different bursal cells we have produced a large panel of monoclonal antibodies (mAbs) by immunizing mice with a BF cell suspension of guinea fowl (Numida meleagris). One of these antibodies (clone: 7H3) was found to recognize a 80 kDa cell surface antigen expressed first in the yolk sac blood island of 2-day-old guinea fowl and chicken embryos, and later detected in the embryonic circulation and primary lymphoid organs. Double immunofluorescence revealed that chB6+ (Bu-1+) B cells of embryonic BF co-express the 7H3 antigen. 7H3 immunoreactivity of the bursal follicles gradually diminished after hatching and only a subpopulation of cortical B cells expressed the 7H3 antigen. In addition, in post-hatched birds 7H3 mAb recognizes all T lymphocytes of the thymus, peripheral lymphoid organs and blood. Embryonic BF injected with the 7H3 mAb showed a near complete block of lymphoid follicle formationIn conclusion, 7H3 mAb labels a new differentiation antigen specific for avian hematopoietic cells, which migrate through the embryonic mesenchyme, colonize the developing BF lymphoid follicles, and differentiate into a subpopulation of cortical B cells. The staining pattern of the 7H3 mAb and the correlation of expression with cell migration suggest that the antigen will serve as valuable immunological marker for studying the ontogeny of avian B cells.

Pathology of offbeat lesions in an outbreak of systemic histomoniasis in desi chickens

An outbreak of multisystemic histomoniasis in six weeks-old desi chickens from a rural based poultry farm holding 500 birds for commercial purpose associated with unusual visceral lesions and high mortality is reported. Birds were reported to have clinical signs of depression, loss of production, yellowish diarrhoea and high mortality. Cumulative mortality of the affected flock was reported to be 60% within a period of 7-10 days. Postmortem examination of the dead birds revealed enlargement of liver covered with pale whitish viscous membranous layer. Hepatic parenchyma showed multifocal, pale whitish to yellow, circular, press button like necrotic lesions varying from 0.3 to 0.5 cm diameter. Few of these lesions were coalescing and appeared as lesions of lymphoma. Spleen was slightly enlarged and congested. Bursa of Fabricius was distended and contained well organised, creamy white, firm mass exhibiting casting of bursal plicae. Kidney revealed multifocal greyish white foci (3-5 mm). Caecum showed moderate longitudinal corrugation of the mucosa. Microscopically, liver showed multifocal necrotic hepatitis with numerous scattered degenerative forms of histomonads surrounded by clear halo, having bull’s eye appearance within the necrotic areas. Mature trophozoites of invasive form of histomonads were also found in the hepatic sinusoids. Bursa of Fabricius revealed severe subacute to chronic cloacal bursitis associated with presence of histomonads within the follicle. Bursal follicles revealed severe lymphoid depletion and cystic degeneration. Multifocal myocarditis, pancreatitis, pneumonia and neuronal degeneration with satellitosis were the other associated lesions observed. Periodic-acid Schiff stained tissue sections revealed intense purple magenta-coloured degenerative forms of histomonads within the necrotic areas of liver, bursa of Fabricius and caecum. This report records the outbreak of naturally occurring multisystemic histomoniasis in layer-type desi chicken associated with unusual lesions including cloacal bursitis, myocarditis, pancreatitis and pneumonia. The present study also validates the earlier postulates of immunosuppression induced primarily by histomoniasis causing severe lymphoid depletion in bursa of Fabricius.

From nasal to basal: single-cell sequencing of the bursa of Fabricius highlights the IBDV infection mechanism in chickens

BackgroundChickens, important food animals and model organisms, are susceptible to many RNA viruses that invade via the nasal cavity. To determine the nasal entry site of the virus and clarify why avians are susceptible to RNA viruses, infectious bursal disease virus (IBDV) was selected because it is a typical avian RNA virus that infects chickens mainly via the nasal route.ResultsFirst, we found that IBDV infected the posterior part of the nasal cavity in chickens, which is rich in lymphoid tissue and allows the virus to be easily transferred to the blood. Via the blood circulation, IBDV infected peripheral blood mononuclear cells (PBMCs) and was transferred to the bursa of Fabricius to damage the IgM + B lymphocyte population. Subsequently, the single-cell RNA sequencing (scRNA-seq) results suggested the more detailed response of different bursal cell populations (B cells, epithelial cells, dendritic cells, and fibroblasts) to IBDV. Regarding B cells, IBDV infection greatly decreased the IgM + B cell population but increased the IgA + B cell population in the bursal follicles. In contrast to B cells, bursal epithelial cells, especially basal cells, accumulated a large number of IBDV particles. Furthermore, we found that both innate RNA sensors and interferon-stimulated genes (ISGs) were highly expressed in the IBDV-infected groups, while dicer and ago2 expression was largely blocked by IBDV infection. This result suggests that dicer-related RNA interference (RNAi) might be an effective antiviral strategy for IBDV infection in avian.ConclusionOur study not only comprehensively elaborates on the transmission of airborne IBDV via the intranasal route and establishes the main target cell types for productive IBDV infection but also provides sufficient evidence to explain the cellular antiviral mechanism against IBDV infection.Graphical

Elucidating antiviral activity of Curcuma longa against H9 N2 influenza virus using embryonated chicken egg model.

Curcumin is a potent antimicrobial herb used traditionally as a spice in culinary. This study was designed to evaluate the antiviral effects of curcuma longa extract against H9 influenza virus. A total of 60 embryonated eggs were equally divided into 5 groups with 12 eggs in each group. Group 1 (G1) served as uninfected negative control. Whereas Group 2 (G2) was kept as positive control infected with known virus @ 0.2 ml with 10-9.3 EID50. Group 3 (G3) was offered Curcuma longa @ 0.2 mg/0.2 ml and H9N2 virus (@ 0.2 ml with 10-9.3 EID50. Similarly, Group 4 (G4) was inoculated with extract of Curcuma longa @ 0.2 mg/0.2 ml per egg, whereas Group 5 (G5) was given Ribazole @ 0.2 ml/ egg. The crude extract and virus were administered on the 15th day of incubation and were checked after every 24 hours up to 96th hour post inoculation by random selection of 3 eggs. Death and survival rate were noted in all groups. Gross and histopathological lesions were also observed. Results revealed that Curcuma longa extract had significantly (p<0.05) reduced the mortality rate of embryos infected with H9N2 virus. In G3, increased lymphocytes and mild fatty changes were seen in liver. Whereas, mature RBCs, plasma cells and some lymphoblast's were observed in Spleen. Similarly, the bursa follicles were with lymphocytic aggregation. The G4 (Curcuma longa) and G5 (Ribazole) were with maximum embryo survival after 48 and 72 h post inoculation. This study revealed potential antiviral activity of Curcuma longa against H9N2 influenza viruses and can be opted as alternative to antibiotics and antiviral drugs to minimize the antimicrobial resistance in human and animal population.

Tissue distribution and developmental changes of PTEN in the immune organs of chicken and effect of IBDV infection on it

Phosphatase and tensin homolog (PTEN), a tumor suppressor gene, functions in antiviral innate immunity and regulates the development and function of T cells and B cells. However, limited information about PTEN is available in poultry. In the present study, quantitative real-time polymerase chain reaction and immunohistochemistry staining were used to study the tissue distribution and developmental changes of PTEN in the main immune organs of chicken. The effects of infectious bursal disease virus (IBDV) infection on PTEN mRNA expression in the bursa of Fabricius (BF) of chickens were also investigated. The results are as follows. 1) The order of PTEN mRNA expression levels at the 18th d of hatching (E18) was: muscle and immune organs (spleen and thymus) > visceral organs (heart, lung, kidney, and liver) > hypothalamus and digestive tracts (duodenum, jejunum, ileum, cecum, proventriculus, BF [originates from cloaca], and cecum tonsil [locates at the lamina propria of cecum]). However, at the 15th d of raising (D15), the PTEN mRNA expression in the heart was the highest among all the tissues, followed by those in the liver, proventriculus, and kidney. The PTEN mRNA expression levels in the rest tissues were very low and were only 1.20 to 19.47% as much as that in the heart (P < 0.05). 2) The changes in the expression of PTEN mRNA in the BF, spleen, and thymus from E15 to D15 had no obvious regularity. PTEN-immunopositive (PTEN-ip) cells in the BF were distributed in epithelium mucosa, bursal follicles and interfollicles before hatching, but only in bursal follicles after hatching. PTEN-ip cells in the spleen were expressed in the periarterial lymphatic sheath from E18 to D15. Most of PTEN-ip cells distributed in the thymic medulla and only a few distributed in the thymic cortex during the whole experiment. 3) Chicken with IBDV infection had a remarkable decrease in PTEN mRNA expression from 1 d postinfection (dpi) to 7 dpi. Although PTEN mRNA level was reversed at 7 dpi, it was still significantly lower than that at 0 dpi (P < 0.05). These findings suggest that the PTEN of chicken might play important roles in the development of embryos and T/B lymphocytes, and the downregulation of PTEN in chickens infected with IBDV might be a mechanism of IBDV evasion from host immunity. Strategies designed to restore PTEN expression may be a therapy for preventing chickens from IBDV infection.

Tandem Mass Tag-Based Quantitative Proteomic Analysis of Chicken Bursa of Fabricius Infected With Reticuloendotheliosis Virus.

Reticuloendotheliosis virus (REV) is a type C avian retrovirus that causes immunosuppression, dwarf syndrome, and lymphoma in infected hosts. In this study, we used tandem mass tag (TMT) labeling and liquid chromatography–tandem mass spectrometry (LC-MS/MS) to characterize protein alterations in chicken bursa of Fabricius, before and after REV infection at 7, 14, 21, and 28 days. Our data showed that 1,127, 999, 910, and 1,138 differentially expressed proteins were significantly altered at 7, 14, 21, and 28 days after REV infection, respectively. Morphological analysis showed that REV infection reduced in cortical lymphocytes, bursal follicle atrophy, and nuclear damage. Bioinformatics analysis indicated these proteins were mainly involved with immune responses, energy metabolism, cellular processes, biological regulation, metabolic processes, response to stimuli, and multicellular organismal process. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway cluster analysis showed that post-infection, proteins were enriched in the cell cycle, Wnt signaling, antigen processing and presentation, cytokine receptor interaction, adenosine 3′,5′-cyclic monophosphate signaling pathway, and NF-κB signaling. In addition, we observed that peroxiredoxin 4 (PRDX4), peroxiredoxin 6 (PRDX6), glutathione peroxidase 3 (GPX3), catalase (CAT), and peroxidasin (PXDN) were involved in oxidative stress. Some heat shock protein (HSP) family members such as HSPH1, DNAJA4, HSPA8, and HSPA4L also changed significantly after REV infection. These findings help clarify interactions between REV and the host and provides mechanistic insights on REV-induced host immunosuppression.

Age Related Histomorphometrical Studies on the Major Lymphoid Organs of Chicken

Background: Hansli chicken is reared in Mayurbhanj and Keonjhar districts of Odisha. They play a vital role in the economic upliftment of poor, landless and marginalised people in the rural areas besides providing them with nutritious egg and meat for consumption.Methods: Hansli chicks and Vencobb broiler chicks were divided into three age groups viz. group I (up to 1 month), group II (1-3 months) and group III (3-6 months) with six birds in each age group. On 4th week, 12th week and 24th week, six birds from each breed were used for the study of histomorphometrical features of the thymus, spleen and bursa of Fabricius. Result: The average thickness of the capsule, cortex and medulla of thymus, average width of thymic lobule and average maximum diameter of Hassall’s corpuscles differed significantly (p≤0.05) between the birds at specific ages. Similarly, the average thickness of the splenic capsule, average width of white pulp, average external transverse and internal longitudinal diameters of trabecular artery, average external longitudinal, internal longitudinal, external transverse and internal transverse diameters of central artery, average longitudinal diameter of capillary, average longitudinal and transverse diameters of splenic nodule, average thickness of PALS and PELS differed significantly (p≤0.05) between the birds at specific ages. The average number of bursal follicles in larger and smaller plicae, average height and width of larger and smaller plicae, average length and width of bursal follicle, average height of columnar cell of pseudostratified FAE and IFE, average nuclear height of FAE and IFE columnar cells differed significantly (p≤0.05) between the birds at specific ages.

Infection of bursal disease virus abrogates the extracellular glycoprotein in the follicular medulla

In the medulla of bursal follicle, only the secretory dendritic cell (BSDC) is furnished with secretory machinery. The granular discharge of BSDC appears in membrane-bound and solubilized forms. Movat pentachrome staining proves that the solubilized form is a glycoprotein, which fills up the extracellular space of follicular medulla. The glycoprotein contributes to bursal microenvironment and may be attached to the surface of medullary lymphocytes. The secretory granules of BSDC may be fused, resulting in large, irregular dense bodies, which are the first sign of BSDC transformation to macrophage-like cells (Mal). To determine the effect of infectious bursal disease virus (IBDV) infection on the extracellular glycoprotein and BSDC, SPF chickens were experimentally infected with IBDV. On the surface of BSDC, the secretory substance is in high concentration, which may contribute to primary binding of IBDV to BSDC. The early distribution of IBDV infected cells is in consent with that BSDC. The IBDV infected BSDC rapidly transforms to Mal in which the glycoprotein staining appears. In the dense bodies, the packed virus particles inhibit the virus particles preventing the granular discharge, which may represent the first, early phase of virus replication cycle. The absence of extracellular glycoprotein results in alteration in the medullary microenvironment and subsequently B cell apoptosis. On the surface of medullary B cells, the solubilized secretory substance can be in much lower concentration, which results in secondary binding of IBDV to B cells. In secondary, late phase of virus replication cycle, the virus particles are not packed in electron dense substance which results in cytolytic lymphocytes and presence of virus in extracellular space. The Mal emigrates into the cortex, where induces inflammation, recruiting heterophil granulocyte and monocyte.