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1.
Skin lymphomas induced in 11 specific-pathogen-free chickens by inoculation at 1 day of age with Marek's disease virus (MDV) were biopsied weekly and examined by electron microscopy and immunohistochemistry. In the sequentially biopsied lymphomas, immature MDV particles (abortive replication) were found only in the nuclei of necrotic lymphoblasts within necrotizing neoplasms. The necrotizing lymphomas were observed in two of the 11 experimental birds and were associated with prominent vascular endothelial cell injury, including fibrinoid necrosis of blood vessels. Nonnecrotizing lymphomas biopsied sequentially from the 11 experimental birds did not contain virus particles of any kind in the lymphoblasts and had no distinct vascular lesions. Immunohistochemically, MDV early antigen (pp38), but not late antigens (glycoproteins B and C), was detected only in the necrotizing lymphomas. These findings indicate that abortive MDV replication mainly occurred in necrotic lymphoblasts, which might have been induced by ischemia.  相似文献   

2.
Feather pulps of 15-to-35-week-old chickens with Marek's disease (MD) lymphomas were examined histopathologically. Of the 64 chickens, 59 (92.2%) had lymphoproliferative (T-type) lesions in the feather pulp. The T-type feather-pulp lesion (FPL) occurred in all regions, but more frequently in the upper column of the pulp. Severe lesions were distributed throughout the feather pulp. Some of the T-type FPLs regressed to inflammatory lesions consisting of necrosis or loss of constituent cells, edema, and infiltration by small lymphocytes, heterophils, and plasma cells. The regressive T-type FPL was usually diffuse throughout the tumorous lesions, but proliferative foci were often seen concomitantly with regressive lesions. The grade and histologic picture of T-type FPLs in chickens correlated well with those of the visceral lymphomas. These findings suggest that the severity of MD lymphoma is predictable without autopsy by examining feather-pulp samples.  相似文献   

3.
Antibody directed against Marek's disease-associated tumor surface antigen (MATSA) was eluted from tumor cells of lymphomas and peripheral blood lymphocytes that were isolated from Marek's disease virus-infected chickens. Feather follicular Marek's disease virus (MDV) antigen could not be demonstrated with this antibody by indirect immunofluorescent (IF) staining. Monoclonal antibody directed against MATSA could completely block the activity of eluted antibody and vice versa. By indirect IF staining using eluted antibody and fluorescein isothiocyanate (FITC) labelled antichicken globulin conjugate. MATSA-bearing cells were detected in MDV infected and herpes virus of turkey (HVT) vaccinated birds. Blocking of immunoglobulin molecules present on B-cells by anti-chicken globulin is critical in this test.  相似文献   

4.
Expression of p27Kip1 was identified in feline lymphoid tissues by immunohistochemistry. In normal lymphoid tissues, p27Kip1 was detected as a distinct nuclear stain in lymphocytes of the follicular mantle zone and interfollicular small lymphocytes, whereas activated lymphoblasts in the germinal center were negative. Lymphoid hyperplasia was similarly immunolabeled but with an expanded mantle zone and marginal zone of p27Kip1-reactive lymphocytes. Both T- and B-cell lymphomas lacked p27Kip1 immunolabel and were determined to be proliferative based on immunohistochemical detection of the Ki-67 antigen. Scattered p27Kip1-immunolabeled lymphocytes were detected throughout the lamina propria of most specimens characterized as lymphoplasmacytic enteritis. The results of this study suggest that the antiproliferative effect of the cell cycle regulator p27Kip1 is abrogated in feline lymphoma, presumably allowing cells to bypass the G1-S checkpoint of the cell cycle.  相似文献   

5.
Efficacy of a bivalent vaccine against Marek's disease   总被引：1，自引：0，他引：1  
A bivalent vaccine was prepared by combining inactivated Marek's disease virus and turkey herpesvirus. The efficacy of this vaccine, compared to turkey herpesvirus and inactivated Marek's disease virus separately, was studied in unsexed White Leghorn chicks which were vaccinated at one day old and then challenged at 21 days old with fowl blood infected with virulent Marek's disease virus. The bivalent vaccine appreciably delayed mortality resulting from Marek's disease and elicited the highest protective efficacy as judged on the basis of Marek's disease-specific mortality and percentage occurrence of lesions. The occurrence, extent and severity of gross lymphomas and microscopic lymphoproliferative lesions in various organs of the bivalent vaccinated birds were less than in the other challenged groups. In addition, the level of viraemia remained consistently and significantly lower in the bivalent vaccinated birds.  相似文献   

6.
An apparently nononcogenic Marek's disease virus (SB-1) and turkey herpesvirus could be readily isolated from spleen, bursa of Fabricius, thymus, and peripheral blood lymphocytes of chickens beginning 4 to 6 days after inoculation, but unlike infections with two isolates of oncogenic Marek's disease virus (JM-10 and CU-2), virus replication in these cells was rare, and necrosis in the organs was essentially absent. Splenic enlargement was observed regularly during the first 4 to 11 days after inoculation, and Marek's disease tumor-associated surface antigen was observed on splenic and other lymphocytes in the four viral inoculation groups. Cellular cytotoxicity of splenic lymphocytes was demonstrated in vitro with cultured Marek's disease tumor cells (MSB-1 lymphoblastoid cell line) as the target in a chromium-release assay. The four viral infections induced sensitized lymphocytes.  相似文献   

7.
Activated, thymus-derived (T) lymphoblasts were exposed to Marek's disease virus and cultivated in attempts to induce in vitro transformation. After 9 to 15 days, colonies or small clusters of proliferating lymphoblasts were observed in cultures from three of a total of 122 attempts. These developed into proliferating cell cultures that resembled conventional Marek's disease (MD) lymphoblastoid cell lines in terms of growth characteristics and morphology. All proliferative cultures were unusual in that 1) the expression of viral internal antigens consistently or periodically was very high (up to 30% of all cells) and 2) the cells deteriorated and/or proliferation ceased in all cases after culture periods of 45-176 days. The proliferative cultures were all characterized as CD2+ and CD3+, Ia-bearing T cells; one was CD4+/CD8- and TCR2+, the other two were CD4-/CD8- and TCR1+. The latter two are the only cultures of MD-infected cells known to be TCR1+.  相似文献   

8.
The metabolic NO pathway, catalyzed by the enzyme NO synthase in macrophages, is a key defense element against viruses and tumors. However, arginase is an other enzyme able to metabolize the substrate L-arginine, and the two enzymes are alternatively regulated by Th1 and Th2 cytokines in murine macrophages. Marek's disease is characterized by strong immunosuppression and development of T-cell lymphomas in chickens. Inoculation of the very virulent strain of MDV RB-1B induced strong and long-lasting arginase macrophage-dependent activity, which was inhibited by L-norvaline in vitro, but induced low NO production in monocytes and splenocytes from highly susceptible B(13)/B(13) chickens. By contrast, in B(21)/B(21) chickens genetically resistant to tumor development, RB-1B induced a weak and transient increase in arginase activity and strong NO production. The vaccinal HVT strain did not induce any arginase activity in monocytes or splenocytes. Moreover, vaccination with HVT prevented tumor appearance after RB-1B challenge and increase in arginase activity, but favored NO production in susceptible chickens. Differential expression of NO synthase and arginase was modulated in chicken macrophages, with IFN-gamma and LPS being strong inducers of both, depending on the type of macrophage, and TGF-beta 1 and PGE(2) stimulating only arginase activity. This increase in arginase activity in macrophages from chickens inoculated with Marek's disease virus might thus be due to a direct effect of the virus on macrophages, possibly through viral products, or to indirect effects on the cytokine balance.  相似文献   

9.
Polymerase chain reaction (PCR) assays for the immunoglobulin and T-cell receptor genes were utilized to determine phenotype and clonality from lymph node cytologic smears and peripheral blood lymphocytes from 10 dogs with lymphoma, before chemotherapy and during remission. Results were compared with those from 13 dogs with a cytologic diagnosis of lymph node hyperplasia. Clonality was identified in 7 of the lymphomas on the basis of either lymph node cytology or peripheral blood lymphocytes before treatment. No lymph node hyperplasia samples were clonal. In 6 of the dogs with lymphoma, clonality was demonstrated during clinical remission. Detection of PCR clonality during clinical remission is an effective means of identifying minimal residual disease in canine lymphoma and thus additional work is warranted to determine if molecular remission is prognostic or predictive for outcome in well-controlled and well-defined lymphoma subtypes.  相似文献   

10.
Telomerase has been studied extensively in human and murine tumors, but little is known about the role of telomerase in the tumor biology of other vertebrate species such as the chicken. We studied the telomerase activity of the lymphoblastoid cell line derived from lymphomas induced by Marek's disease virus (MDCC-MSB1) compared with another avian cell line (PA5) and peripheral blood lymphocytes (PBL) using the telomeric repeat amplification protocol (TRAP) Assay. Telomerase activity in MDCC-MSB1 was 4.5 times greater than in the PA5 cell line and normal avian lymphocytes. These results demonstrate for the first time that telomerase is more intense in one transformed cell line than in normal cells, suggesting a potential role for telomerase in carcinogenesis induced by an avian virus.  相似文献   

11.
Marek's disease virus (MDV) is an oncogenic cell-associated herpesvirus that causes T-cell lymphoma in chickens. Lymphoproliferative neoplasms in Marek's disease (MD) occur in various organs and tissues, including the viscera, peripheral nerves, skin, gonads, and musculatures. MDV is restrictively produced in the feather follicle epithelial (FFE) cells, and it gains access to the external environment via infected cells or as infectious enveloped cell-free virus particles. The goals of the present study were to 1) determine whether the MDV-induced skin lesions are neoplastic in nature or inflammatory reactions to viral infection, 2) determine whether physical presence of feather follicles (FF) is necessary for skin tumor development, and 3) study the role of skin epithelial cells not associated with feathers or FF in the replication and dissemination of infectious virus particles. Scaleless chickens that produce only a few scattered feathers and no sculate scales along the anterior metatarsi were used as a unique model to study the pathogenesis of dermal lesions. Histologic and immunohistochemical analysis revealed that the cutaneous lesions were tumorous as was manifested by massive accumulation of lymphoblasts and extensive activation of meq oncoprotein, the hallmark of MDV oncogenesis, within the skin lesions. Neoplastic cutaneous lesions in the scaleless chickens indicate that feather follicles are not necessary for skin tumor development. Finally, our preliminary data indicate that inoculation with supernatant fluid from homogenized and sonicated skin samples of MDV-infected scaleless chickens induces MD in susceptible birds, suggesting that skin epithelial cells not associated with FF also harbor infectious viral particles.  相似文献   

12.
The average percentage of acid alpha naphthyl acetate esterase reacting lymphocytes (APARL) was enumerated in the peripheral blood of chickens challenged with Marek's disease after vaccination with either turkey herpesvirus (HVT), inactivated Marek's disease virus (IMDV) or a mixture of the two (bivalent vaccine). A gradual increase in APARL value was noticed in the vaccinated chickens from day 7 to 70 after challenge with a virulent Marek's disease virus. The increase was consistent and significantly higher in bivalent (HVT plus IMDV) than in HVT-vaccinated chickens while the slight increase noticed in IMDV vaccinated-challenged birds was inconsistent.  相似文献   

13.
A study was conducted on an outbreak of Marek's disease in a commercial poultry farm containing 8500 chickens in central Ethiopia. On repeated visits, farm and flock history was collected, sick birds were examined and clinical signs and daily mortality were recorded. A total of 80 (27 sick and 53 dead) birds 12-22 weeks old, were collected, autopsied and examined. The mortality rate was 46% for the first 14 weeks of the outbreak. Acute and chronic (classical) forms of the disease, the respective occurrence of which varied significantly (p<0.01) in young (14.6% vs 85.4%) and adults (48.7% vs 51.31%) were manifested. All the autopsied birds had gross and microscopic lesions indicative of Marek's disease in the peripheral nerve(s) and/or visceral organs. Lesions involving peripheral nerves and visceral lymphomas were recorded mainly in adults (28/35, 80%) and young birds (34/45, 75%), respectively. These differences in the two age groups were statistically significant (p<0.01). Young birds seem to be highly susceptible to the acute disease. Poor management, overstocking and lack of vaccination might have favoured the outbreak. Marek's disease causes considerable economic loss and is a major threat to poultry production in Ethiopia. This report emphasizes that Marek's disease should be considered as a disease of economic significance in chicken production in Ethiopia and warrants due attention.  相似文献   

14.
Abstract: Immunohistochemical techniques were used to examine 29 cases of equine lymphoma for estrogen receptor (ER) and progesterone receptor (PR) expression. The lymphomas examined included T-cell-rich large B-cell lymphomas, B-cell neoplasms, and T-cell lymphomas. The individual cases were also classified according to the anatomic location of the tumors. One normal equine lymph node was also examined for ER and PR expression. All of the cases of equine lymphoma and the normal lymph node were negative for ER. A total of 16/29 (55%) PR-positive lymphomas were identified. Seven of the 12 (58%) T-cell-rich large B-cell lymphomas were positive, 7/11 (64%) B-cell tumors were positive, and 2/6 (33%) T-cell neoplasms were positive. Anatomically, 6/9 (66%) subcutaneous lymphomas were PR positive, 3/5 (60%) intrathoracic lymphomas were positive, 1/4 (25%) intra-abdominal lymphomas were positive, 2/5 (40%) intra-abdominal/intrathoracic lymphomas were positive, 1/2 (50%) upper airway lymphomas were positive, and 3/3 (100%) splenic lymphomas were positive. One case involving abdominal and thoracic tumors and leukemia was negative for PR expression. The normal lymph node contained a low percentage (1.9%) of PR-positive lymphocytes. The presence of PR in neoplastic equine lymphoid tissue indicates that these tumors may be responsive to serum progesterone. Also, identification of PR-positive cells in the normal lymph node suggests that PR may be constitu-tively expressed in normal equine lymphocytes. Further studies are needed to quantify PR levels in normal and malignant equine lymphoid tissue and to determine the usefulness of either progestin or antiprogestin drugs in the management of equine lymphoma.  相似文献   

15.
Gastrointestinal lymphomas were identified in 120 cats between 1995 and 2006. Lymphomas were classified according to the World Health Organization (WHO) scheme. Cats with mucosal T-cell lymphoma (n = 84) predominated and had a median survival of 29 months. Mucosal T-cell lymphoma matched WHO enteropathy-associated T-cell lymphoma (EATCL) type II. Epitheliotropic T-cell infiltrates were present in 62% of cats and occurred as clusters or diffuse infiltrates of small to intermediate-sized T cells in villous and/or crypt epithelium. Similar lymphocytes infiltrated the lamina propria in distinctive patterns. Cats with transmural T-cell lymphoma (n = 19) had a median survival of 1.5 months. Transmural T-cell lymphoma matched WHO EATCL type I. Epitheliotropic T-cell infiltrates were present in 58% of cats. Large lymphocytes (n = 11), mostly with cytoplasmic granules (LGL-granzyme B+) (n = 9) predominated. Transmural extension across the muscularis propria characterized the lesion. Both mucosal and transmural T-cell lymphomas were largely confined to the small intestine, and molecular clonality analysis revealed clonal or oligoclonal rearrangements of T-cell receptor-γ in 90% of cats. Cats with B-cell lymphoma (n = 19) had a median survival of 3.5 months. B-cell lymphomas occurred as transmural lesions in stomach, jejunum, and ileo-cecal-colic junction. The majority were diffuse, large B-cell lymphomas of centroblastic type. In conclusion, T-cell lymphomas characterized by distinctive mucosal architecture, CD3 expression, and clonal expansion predominated in the feline gastrointestinal tract.  相似文献   

16.
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17.
Day-old quails experimentally infected with Marek's disease (MD) virus of quail origin developed lymphoid tumors. The severity of the disease increased considerably with serial passage. Tumor transplants could be made with cells derived from gross tumors in skeletal muscles, spleen cells, and blood from MD-affected quails. After five to six serial transplants, the tumor could not be transplanted further. Marek's disease tumor-associated surface antigen (MATSA) was demonstrated in lymphoid cells of spleen and peripheral blood lymphocytes of MD-affected quails. The MATSA of quail differed from the MATSA of chicken. Chickens were susceptible to MD virus isolated and propagated in quails.  相似文献   

18.
BACKGROUND: Uniquely rearranged immunoglobulin and T-cell receptor gene sequences can be amplified and electrophoretically separated by size to detect a clonal population of lymphocytes. OBJECTIVE: The purpose of this study was to determine whether the polymerase chain reaction (PCR) detects neoplastic (clonal) lymphocytes more frequently than do microscopic methods. METHODS: We identified neoplastic lymphocytes in peripheral blood by both routine and standardized microscopic examination of blood smears and by PCR amplification of blood-derived DNA and compared the 3 methods for frequency of detection of leukemic involvement. For standardized microscopic examination (200 leukocytes counted on Wright-Giemsa-stained blood smears), samples were categorized as negative (1% prolymphocytes, no lymphoblasts), or positive (>/=1 lymphoblast). A PCR-amplified sample was positive if 1 or 2 discrete bands were seen on the gel, or negative if no bands, a smear, or a faint ladder was seen. RESULTS: Using PCR, neoplastic lymphocytes were detected in peripheral blood 2.5 times more frequently than with routine or standardized microscopic evaluation. Eighty-three percent of samples negative by microscopy were positive by PCR. CONCLUSION: PCR is more sensitive than microscopy for the detection of clonal lymphocytes in peripheral blood. The results of this study also suggest that neoplastic lymphocytes circulate in peripheral blood at a higher frequency than previously reported. PCR may be useful for detecting or phenotyping lymphoma, monitoring response to therapy, identifying recurrence, and screening breeds at risk.  相似文献   

19.
Cytologic criteria were evaluated for their diagnostic value in liver disease in dogs. Therefore, histopathologic and cytologic examination was performed on liver biopsy samples of 73 dogs with liver diseases and 28 healthy dogs. Logistic regression analysis was used to select the measured parameters to be included in a multistep approach. With the logistic regression method, different characteristic cytologic parameters could be defined for each histopathologic diagnosis. In malignant lymphoma of the liver, the presence of large numbers of lymphoblasts with a minimum of 5% of all cells was found. Clusters of epithelial cells with several cytologic characteristics of malignancy intermixed with normal hepatocytes were indicative of metastatic carcinoma or cholangiocellular carcinoma. Liver cells in hepatocellular carcinoma were characterized by a high nucleus/cytoplasm ratio, large cell diameters, increased numbers of nucleoli per nuclei, small numbers of cytoplasmic vacuoles, and frequently, small numbers of lymphocytes. Extrahepatic cholestasis was characterized by excessive extracellular bile pigment in the form of biliary casts, an increased number of nucleoli within hepatocytes, decreased hepatic cell size, and low numbers of lymphocytes. In destructive cholangiolitis, increased numbers of neutrophils and a small mean nuclear size within hepatocytes were seen. Acute and nonspecific reactive hepatitis are diagnosed based on the presence of moderate reactive nuclear patterns, including more pronounced chromatin, prominent nucleoli, increased numbers of inflammatory cells, excluding lymphocytes, and the absence of increased numbers of bile duct cell clusters. Increased number of mast cells also was indicative of nonspecific reactive hepatitis. Important cytologic criteria for the diagnosis of liver cirrhosis, in addition to chronic hepatitis, are intracellular bile accumulation and increased numbers of bile duct cell clusters. In summary, the stepwise approach based on logistic regression presented in this study might be helpful in the objective cytologic diagnosis of hepatic diseases.  相似文献   

20.
Marek's disease (MD) is a highly contagious viral disease of chickens (Gallus gallus domesticus) caused by MD virus (MDV), characterized by paralysis, neurologic signs, and the rapid onset of T-cell lymphomas. MDV-induced T-cell transformation requires a basic leucine zipper protein called Marek's EcoRI-Q-encoded protein (Meq). We have identified mutations in the coding sequence of Meq that correlated with virus pathotype (virulent, very virulent, and very virulent plus). The aim of this study was to determine whether recombinant viruses could be isolated based on Meq expression through in vivo selection. Chicken embryo fibroblasts (CEFs) were cotransfected with an rMd5 strain-based Meq deletion virus (rMd5deltaMeq) and meq loci from strains representing different pathotypes of MDV. Transfected CEFs were inoculated into chickens in two independent studies. We were able to isolate a single recombinant virus, rMDV-1137, in a contact-exposed chicken. rMDV-1137 had recombined two copies of the meq gene of RB-1B and was found to have pathogenicity similar to both RB-1B and rMd5 parental strains. We found the RB-1B- and rMd5-induced lymphomas showed differences in composition and that rMDV-1137-induced lymphomas were intermediate in their composition. We were able to establish cell lines from both RB-1B- (MDCC-UD35, -UD37) and rMDV-1137 (MDCC-UD36, -UD38)-induced, but not rMd5-induced, lymphomas. To date, no rMd5- or parent Md5-transformed T-cell lines have been reported. Our results suggest that 1) a recombinant MDV can be selected on the basis of oncogenicity; 2) changes in Meq sequence seem to affect tumor composition and the ability to establish cell lines; and 3) in addition to meq, other genomic loci affect MDV pathogenicity and oncogenicity.  相似文献   

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