Induction of IL-2 and lymphokine activated killer cells in the cat

We have described the use of a cloned murine IL-2-dependent T-cell line to directly measure feline IL-2. Concanavalin A stimulated feline peripheral blood lymphocytes produced an IL-2-rich supernatant that supported the growth of this murine IL-2-dependent T-cell line. In addition to producing IL-2, Con A stimulated killer cells in PBL were cytotoxic for the FeLV transformed tumor cell line FL74. Incubating feline PBL with a cocktail of the calcium ionophore A23187 and phorbol ester also led to the generation of cytotoxic cells as well as the production of high levels of IL-2. Finally, IL-2-rich supernatant was able to stimulate cytotoxic activity in PBL from normal cats.     

The use of immunohistochemistry and the polymerase chain reaction for detection of feline leukemia virus and feline sarcoma virus in six cases of feline ocular sarcoma

Ocular sarcoma was diagnosed by light microscopic examination in enucleated globes ( n  = 4), orbital tissue biopsy ( n  = 1) and ocular evisceration contents ( n  = 1) from six cats. To determine if feline leukemia virus (FeLV) or a replication-defective FeLV, feline sarcoma virus (FeSV), was present in these ocular sarcomas, immunohistochemistry (IHC) and polymerase chain reaction (PCR) for FeLV were utilized. Immunohistochemical staining for FeLV glycoprotein 70 (gp70) was performed on all six formalin-fixed, paraffin-embedded tumors using an avidin–biotin complex technique. DNA was extracted from each specimen and a 166 bp region of the FeLV long-terminal repeat (LTR) was amplified by PCR. All tumors were composed primarily of spindle cells; two neoplasms had PAS-positive basement membrane enveloping areas of spindle cells. All tumors involved the uvea and five of six tumors showed transcleral extension, one of which invaded the optic nerve. Immunohistochemical staining for FeLV gp 70 was negative. PCR to amplify a portion of the FeLV LTR was negative. Based on these findings of these limited number of cases, FeLV/FeSV may not play a role in the tumorigenesis of feline ocular sarcomas. However, additional tumors representing all morphological subtypes should be investigated for the presence of viral antigen and DNA. It is important to determine the etiology and pathogenesis of these malignant ocular sarcomas. If the cell of origin and pathogenesis involve ocular and lenticular injury, and FeLV/FeSV is not present, then the clinical management of cases of feline ocular trauma, uveitis and glaucoma may prevent the development of this tumor.     

Molecular pathogenesis of feline leukemia virus-induced malignancies: insertional mutagenesis

Feline leukemia virus (FeLV), which is subclassified into three subgroups of A, B and C, is a pathogenic retrovirus in cats. FeLV-A is minimally pathogenic, FeLV-C can cause pure red cell aplasia, and FeLV-B is associated with a variety of pathogenic properties such as lymphoma, leukemia and anemia. FeLV-induced neoplasms are caused, at least in part, by somatically acquired insertional mutagenesis in which the integrated provirus may activate a proto-oncogene or disrupt a tumor suppressor gene. The common integration sites for FeLV have been identified in six loci with feline lymphomas: c-myc, flvi-1, flvi-2 (contains bmi-1), fit-1, pim-1 and flit-1. Oncogenic association of the loci includes that c-myc is known as a proto-oncogene, bmi-1 and pim-1 have been recognized as myc-collaborators, fit-1 appears to be closely linked to myb, and flit-1 insertion is shown to be associated with over-expression of a cellular gene, e.g. ACVRL1. Thus, identification of common integration sites for FeLV is a tenable model to clarify oncogenesis. Recent advances in molecular biology and cytogenetics have developed to rapidly detect numbers of retroviral integration sites by genome-wide large-scale analyses. Especially, polymerase chain reaction (PCR)-based strategies and chromosome analyses with fluorescence in situ hybridization (FISH) will be applicable for studies on FeLV.     

Monoclonal antibodies to feline lymphocyte membranes recognize the leukocyte-common antigen (CD45R).

By immunization of BALB/c mice with a feline T lymphoblastoid cell line, MYA-1 cells, two types of lymphocyte-specific monoclonal antibodies (mAbs) were obtained. The 220/205/190 kd protein defined by 2F11 mAb is highly expressed on the surface of MYA-1 cells and another feline T lymphoma cell line, FL74 cells. The protein is also expressed on normal feline thymocytes, splenocytes and feline peripheral blood mononuclear cells (PBMCs). Another mAb, 17B10, caused similar results as those of 2F11 except for its low reactivity with FL74 cells. The second type of mAb, 15B3, defined the 220 kd protein. The reactivities of this mAb with MYA-1 cells, FL74 cells, PBMCs and feline splenocytes were lower than the former two mAbs, and did not react to feline thymocytes. On the other hand, 17B10 and 15B3 defined partial populations of MYA-1 and FL74 cells recognized by 2F11. The cells defined by the 2F11 and 17B10 are all leukocytes in spleen and lymph node. In contrast, 15B3 defined most of the cells in B cell area and partially in T cell area. These results suggested that 2F11 and 17B10 recognized the specific antigen of 220/205/190 kd of the leukocyte-common antigen (L-CA) family, CD45R, with different epitopes, and that 15B3 defined the distinct antigen of 220 kd on CD45R.     

Differential cytokine expression in T cell subsets from bovine peripheral blood

Although distinct cytokine expression in T cell subsets is well understood in mice and humans, limited information is available on bovine T cell subsets. In the present study, we analyzed the mRNA expression of 10 kinds of cytokines and CD25 expression in CD4⁺, CD8⁺, WC1⁺ and WC1^-γδ T cell subsets in bovine peripheral blood by Concanavalin A (Con A) stimulation. CD25 expression was significantly increased in CD4⁺, CD8⁺ and WC1⁺γδ T cells, but not in WC1^-γδ T cells by Con A stimulation. In CD4⁺ T cells, the mRNAs of Interleukin (IL)-2, IL-6, IL-10, interferon (IFN)-γ, tumor necrosis factor (TNF)-α, TNF-β and transforming growth factor (TGF)-β were expressed in control cultures, and IL-3, IL-4 and granulocyte-macrophage colony stimulating factor (GM-CSF) were newly expressed when the cells were stimulated with Con A. CD8⁺ T cells expressed the mRNAs of IL-6, TNF-α, TNF-β and TGF-β in control cultures, and newly expressed those of IL-2, IFN-γ and GM-CSF, but did not express those of IL-3, IL-4 or IL-10 after Con A stimulation. The cytokine expression profile of WC1⁺γδ T cells was similar to that of CD8⁺ T cells. However, WC1^-γδ T cells did not express any cytokine mRNA except TGF-â mRNA. These results will contribute to elucidate the participation of T cell subsets in immune responses against infectious disease in cattle.     

Parameters of production and partial characterization of feline interleukin 2

The conditions for the production of feline interleukin 2 (IL-2) from peripheral blood leukocytes (PBL) and splenocytes by concanavalin A (Con A) stimulation are described. Feline IL-2 was quantitated by measuring DNA synthesis in the murine IL-2-dependent cell line, CTLL-20. In addition, feline IL-2 was generated for the maintenance of long-term cultures of Con A-stimulated feline PBL and for biochemical characterization. Finally, IL-2 production was evaluated from the PBL of feline leukemia virus (FeLV)-infected cats. Con A at 9.6 micrograms/ml produced a plateau of peak IL-2 activity from 24 to 48 h following stimulation. The tumor promoter, phorbol myristic acetate, stimulated feline IL-2 production and enhanced Con A-stimulated feline IL-2 production. Fetal calf serum (FCS) was not required for IL-2 production; however, FCS at 5% (v/v) allowed for maximal Con A-stimulated IL-2 production. Feline IL-2 generated from Con A-stimulated splenocytes migrated with an apparent molecular size of 13.7 to 23 kD by gel filtration chromatography and supported the proliferation of Con A-activated feline PBL at a final concentration of 0.3 to 0.9 units/ml.     

Persistent upregulation of MHC class II antigen expression on T-lymphocytes from cats experimentally infected with feline immunodeficiency virus.

A significant elevation in the percentage of CD4+ and CD8+ T-lymphocytes expressing major histocompatibility complex (MHC) Class II antigens was observed in the blood of cats shortly after they were experimentally infected with feline immunodeficiency virus (FIV). In addition to an increase in the relative proportion of T-lymphocytes expressing Class II antigens, there was an increase in the density of Class II antigens on the cell surface. These elevations were still evident at the completion of the 5 month study. A second group of cats that had been infected with FIV for almost 5 years, and with either normal or abnormally low levels of CD4+ T-lymphocytes, had similar elevations in MHC II expression, suggesting that such abnormalities are lifelong. Cats with chronic (2 year) feline leukemia virus (FeLV) infection or dual FIV/FeLV infections also showed similar alterations in MHC II expression on CD4+ and CD8+ T-lymphocytes, suggesting that these alterations were not FIV specific. Feline T-lymphocytes expressed more MHC II antigen and interleukin-2 (IL-2) receptor following stimulation in vitro with conconavalin A and IL-2, demonstrating that feline T-lymphocytes respond to activation signals in a manner similar to T-lymphocytes of other species. However, changes in MHC II expression on T-cells of FIV infected cats were not explainable by viral induced T-cell activation alone, because FIV infected cats with elevated MHC II expression did not have coincident elevations in IL-2 receptor expression.     

UBC13对支气管哮喘模型小鼠Th2、Th17型细胞极化的影响

试验旨在探究UBC13蛋白对支气管哮喘小鼠体内Th2、Th17细胞极化的影响。18只BALB/c小鼠随机均分为3组：PBS组、哮喘模型（OVA）组和UBC13蛋白（UBC13）组,OVA组和UBC13组采用卵清蛋白（OVA）和脂多糖（LPS）进行致敏和雾化建立哮喘模型,其中UBC13组于每次雾化前0.5 h腹腔注射100 μg UBC13蛋白。末次雾化激发24 h后处死小鼠,采集样品,通过HE染色观察肺脏切片病理学变化、PAS染色观察气道黏液的分泌,ELISA法检测血清IgE浓度和肺支气管肺泡灌洗液（BALF）上清中IL-4、IL-5和IL-17A的水平,实时荧光定量PCR法检测肺脏Th2型相关因子IL-4、IL-5、IL-13、IFN-γ mRNA和Th17型细胞因子IL-1β、IL-6、IL-17A、IL-23 mRNA的相对表达量。结果显示,试验成功建立了哮喘模型,与PBS组相比,OVA组IgE浓度极显著上升（P < 0.01）,肺脏病理切片炎性细胞浸润和中性黏液分泌现象明显,肺脏中IL-1β、IL-4、IL-6、IL-13和IL-17A mRNA相对表达量均极显著升高（P < 0.01）,IL-5和IL-23 mRNA相对表达量显著升高（P < 0.05）,IFN-γ mRNA相对表达量极显著下降（P < 0.01）,BALF中IL-4、IL-5和IL-17A的水平极显著上升（P < 0.01）;与OVA组相比,UBC13组IgE浓度显著降低（P < 0.05）,病理切片炎性细胞浸润现象减轻、黏液分泌减少,肺脏IL-1β、IL-4、IL-17A、IL-13和IL-23 mRNA相对表达量均显著下降（P < 0.05）,IFN-γ mRNA相对表达量显著升高（P<0.05）;IL-6 mRNA相对表达量极显著下降（P < 0.01）,BALF中IL-5的水平极显著下降（P < 0.01）,IL-4的水平显著下降（P < 0.05）,IL-17A的水平无显著差异（P > 0.05）。由此可见,UBC13蛋白能下调Th2和Th17型细胞因子的表达量,影响哮喘模型Th2和Th17细胞的极化。     

烟碱对LPS诱导的兔子宫内膜上皮细胞炎症因子及前列腺素分泌的影响

试验旨在探索α7烟碱乙酰胆碱受体（α7 nicotinic acetylcholine receptor,α7nAChR）的高亲和力激动剂烟碱对脂多糖（lipopolysaccharides,LPS）诱导的兔子宫内膜上皮炎症的作用机制。分离发情后期兔的子宫内膜上皮细胞,用100 ng/mL LPS对细胞进行炎性刺激12 h。用CCK8法检测不同浓度烟碱（5、10和20 μg/mL）对细胞存活率的影响,筛选合适浓度的烟碱进行后续试验。将细胞分为对照组（CON）、LPS、LPS+烟碱、LPS+烟碱+甲基牛扁碱（MLA）（α7nAChR的特异性颉颃剂）组,通过ELISA法检测细胞培养上清液中白细胞介素-1β（interleukin 1β,IL-1β）、IL-6、IL-8、肿瘤坏死因子-α（tumor necrosis factor,TNF-α）、前列腺素E₂（prostaglandin E₂,PGE₂）和前列腺素F_2α（PGF_2α）的含量。试验成功分离兔子宫内膜上皮细胞,且传至第5代仍保持良好的生长状态。CCK8检测结果显示,20 μg/mL烟碱组细胞存活率显著降低（P<0.05）,10 μg/mL烟碱对细胞存活率无显著影响（P>0.05）,所以选择10 μg/mL烟碱进行后续试验。ELISA结果显示,与对照组相比,LPS组IL-1β、IL-6、IL-8、TNF-α、PGE₂和PGF_2α的含量显著增加（P<0.05）;与LPS组相比,LPS+烟碱组显著降低IL-1β、IL-6、IL-8、TNF-α、PGE₂和PGF_2α的含量（P<0.05）,LPS+烟碱+MLA组炎性因子和前列腺素的含量差异不显著（P<0.05）。以上结果表明,烟碱对LPS诱导的兔子宫内膜上皮细胞分泌IL-1β、IL-6、IL-8、TNF-α、PGE₂和PGF_2α具有下调作用,推测烟碱通过α7nAChR介导炎性因子和前列腺素分泌下调而发挥抗炎作用,该结果可为研究α7nAChR作为子宫内膜炎治疗靶点的药物选择提供参考。     

A feline retrovirus induced T-lymphoblastoid cell-line that produces an atypical alpha type of interferon

A cell-line, designated LSA-1, was derived from a thymic lymphosarcoma that occurred in a cat with experimentally induced feline leukemia virus (FeLV) infection. LSA-1 cells possessed surface receptors and antigens of normal T-lymphocytes, but were unresponsive to interleukin-2 stimulation. The LSA cell-line was found to constitutively produce and release an interferon into the culture supernatants. Production of this interferon was enhanced in certain clones of the original LSA-1 cell lines. The interferon produced by LSA-1 cells and some of its clones was compared to the standard alpha, beta, and gamma interferons of cats. Unlike alpha and beta interferons, which were acid, SDS, and heat stable, LSA interferon was acid labile and SDS and heat stable. In comparison, standard feline gamma interferon was acid, SDS, and heat labile. LSA interferon had a molecular weight of 20,000 daltons, compared to 17-19,000 daltons for gamma, 19-25,000 for beta, and 25-45,000 daltons for alpha interferons. Standard feline interferons were active only on cat cell lines, with the exceptions of alpha interferon, which also reacted with MDCK canine cells. LSA interferon resembled the standard feline alpha interferon because it also reacted with feline and canine cells. It was concluded that LSA interferon was an atypical acid labile alpha interferon, resembling in this respect the abnormal alpha interferon seen in humans with AIDS and SLE, and mice with retrovirus infections. LSA-1 cells produced high levels of FeLV structural proteins but very little infectious virus. This effect was due to endogenously produced interferon; LSA cell clones that were selected for low interferon production produced much higher levels of infectious FeLV than parent cells or clones selected for high interferon production. Cat cells pretreated with LSA or with standard feline alpha and beta interferons, and then infected with FeLV, produced high levels of FeLV proteins but very little infectious virus.     

La leucose feline: Developpements recents sur l''etiologie et l''immunoprevention de la maladie

Feline leukemia is a useful model for malignant hematopoïetic tumor studies. It is caused by a type C, RNA virus, the Feline Leukemia virus (FeLV), transmitted horizontally, and widespread in the cat population.The presence of DNA sequences and virus specific RNA expression in cell cultures of SPF cats and cat embryos, indicates a vertical transmission may occur.These FeLV-related sequences in virus negative lymphosarcoma, almost from older cats, indicate that in certain FeLV related diseases the viral replication may not occur. An endogenous ecotropic feline virus may also explain this finding. The absence of FeLV gene expression in some lymphomatous cats—many older—suggest that, in these cats, spontaneous lymphoma may not be caused by FeLV.The widespread occurrence of feline xenotropic endogenous virus RD-114 gene, in feline lymphoma, suggest that expression of certain functions of this virus may be involved etiologically in the development of lymphoid tumors in the cat.Nevertheless, immunisation against FeLV would provide a good prevention against the main part of the feline lymphosarcomas and other FeLV-related diseases. Inactivated FeLV does not provide a good immunisation in young cats. By contrast a good protection against tumoral development is obtained by vaccination using the Feline oncogenic virus cell membrane antigen (FOCMA).     

猴头菇多糖对MDRV感染RAW264.7细胞TLR3/TRIF诱导表达及病毒复制的影响

试验旨在探究猴头菇多糖（HEP）预处理RAW264.7细胞对番鸭呼肠孤病毒（MDRV）复制的影响及其机制,从Toll样受体3/β干扰素TIR结构域衔接蛋白（TLR3/TRIF）信号通路解析HEP在调节MDRV所致的雏番鸭机体免疫抑制中的作用机制并提供体外试验参考。试验设空白对照组（BCG）、病毒感染对照组（VCG）、HEP对照组（HCG）和HEP预防病毒感染组（HPG）,RAW264.7细胞在MDRV感染12和24 h后,通过Western blotting检测各组细胞中TLR3、TRIF和肿瘤坏死因子受体相关因子6（TRAF6）的蛋白表达量;病毒感染24 h后,用ELISA法检测各组细胞培养液中肿瘤坏死因子-α（TNF-α）、白介素-10（IL-10）、IL-6、IL-1β、干扰素-β（IFN-β）的含量。TCID₅₀检测结果表明,MDRV病毒的TCID₅₀为10^3.46。病毒感染后12 h,细胞未出现明显变化;病毒感染后24 h,细胞变圆;病毒感染后36 h,细胞大量死亡。MDRV在RAW264.7细胞中的复制结果显示,在感染病毒12~24 h内,σNS的表达量呈现上升趋势;在24~36 h,σNS的表达量维持在较高水平。Western blotting结果显示,与空白对照组相比,VCG组细胞TLR3、TRIF和TRAF6蛋白的表达量在感染后12和24 h均显著升高（P<0.05）,HCG组TRIF蛋白的表达量均显著升高（P<0.05）;与感染组相比,HPG组的σNS、TLR3、TRIF和TRAF6蛋白表达量在病毒感染12和24 h均显著降低（P<0.05）。ELISA检测结果显示,与空白对照组相比,VCG组细胞培养液中TNF-α、IL-6、IL-1β和IFN-β的含量均显著升高（P<0.05）;与感染组相比,HPG组细胞培养液中TNF-α、IL-6、IL-1β含量均显著降低（P<0.05）,IFN-β的含量显著升高（P<0.05）。结果表明,HEP可调节MDRV感染诱导RAW264.7细胞TLR3信号转导通路活化,抑制TLR3信号转导通路下游产物TNF-α、IL-10、IL-6和IL-1β的过度表达,同时上调IFN-β的表达,从而抑制MDRV在RAW264.7细胞中的复制。     

Role of CXCR4 and SDF-1 in mammary tumor metastasis in the cat

It has recently been suggested that the chemokine receptor CXCR4 and its ligand SDF-1 (CXCL12) promote metastasis of various cancers in humans. Since feline mammary tumors also metastasize to distant organs frequently, we used real-time quantitative PCR to examine the expression of feline CXCR4 (fCXCR4) in ten feline mammary tumor cell lines and seven feline mammary tumor tissues, and also the expression of feline SDF-1 (fSDF-1) in various organs. Cell lines derived from metastatic regions expressed more fCXCR4 than those derived from primary tumors. Mammary tumor tissues overexpressed more fCXCR4 than normal mammary tissues. Organs with high levels of fSDF-1 expression represent common sites of metastasis. Migration assays using the feline mammary tumor cell line NAC were also performed to test the activity of TN14003 and TC14012, antagonists of human CXCR4, to antagonize fCXCR4 expressed on NAC cells. TN14003 and TC14012 inhibited migration of NAC cells. We conclude that fCXCR4 may be a therapeutic target for feline mammary tumors.     

Interleukin 4 increases CCR9 expression and homing of lymphocytes to gut-associated lymphoid tissue in chickens

The effects of in vitro and in vivo IL-4 supplementation on thymocyte and splenocyte CCR9 mRNA amount and migration were studied. Thymocytes, splenocytes, splenocytes+thymocytes (2:1), and splenocytes+bursocyte cells (2:1) were supplemented with either 0 or 5 ng/ml IL-4 for 5d. CCR9 mRNA was undetectable in all experimental groups supplemented with 0 ng/ml IL-4. IL-4 treatment (5 ng/ml) upregulated (P=0.01) CCR9 mRNA only in the splenocyte+thymocyte cell culture. IL-4-mediated CCR9 mRNA induction in the splenocyte+thymocyte cell culture was dependent on the in vitro dose of IL-4 supplementation. IL-4-treated splenocyte+thymocyte cells when injected in vivo preferentially migrated to cecal tonsils. In vivo supplementation of IL-4 was achieved through in ovo injection of recombinant chicken IL-4 plasmid. Cecal tonsils in chicks hatched from IL-4-plasmid-injected eggs weighed more, had a higher amount of CCR9 mRNA, and had a higher percentage of CD8(+) cells than cecal tonsils from chicks hatched from PBS-injected eggs. It could be concluded that IL-4 induces CCR9 mRNA in thymocytes and splenocytes and directs the migration of cells to gut-associated lymphoid tissue.