尼罗罗非鱼鼠李糖凝集素 (RBL-1)在非特异性细胞防御病原菌感染中的功能

为了探究鼠李糖凝集素（Rhamnose-binding lectin, RBL）在硬骨鱼非特异性细胞防御病原菌感染中的作用,本研究以尼罗罗非鱼为研究模型,首先通过分离头肾单核/巨噬细胞进行体外菌应激实验,发现在罗非鱼两种重要的致病菌-无乳链球菌（Streptococcus agalactiae）和嗜水气单胞菌（Aeromonas hydrophila）应激后,尼罗罗非鱼L-鼠李糖凝集素1（OnRBL-1）的表达量显著上调。然后,通过荧光定量PCR（qRT-PCR）检测发现OnRBL-1重组蛋白能够调节病原菌诱导细胞炎症因子的表达,包括显著抑制菌诱导的IL-6、IL-8和TNF-α的表达,和促进IL-10和TGF-β的表达。此外,通过流式细胞术检测证实OnRBL-1具有促进单核/巨噬细胞的吞噬作用,同时增强呼吸爆发水平和上调活性氧的释放。以上研究结果表明,OnRBL-1在罗非鱼单核/巨噬细胞非特异性细胞防御中发挥重要的调节作用。本研究为探讨RBL-1在硬骨鱼宿主防御病原菌感染中的功能提供了参考,并有助于完善和丰富硬骨鱼类RBL的功能和在抗菌免疫应答中的基础理论体系,具有重要的科学意义。     

Detection of an Ehrlichia bovis-like Organism in Cultured Buffalo Monocytes

Monocytes from a buffalo were cultured in RPMI 1640 medium following separation of plasma by the erythrocyte sedimentation technique and subsequent separation of mononuclear cells by density gradient centrifugation. Growth of an organism considered to be Ehrlichia bovis was noticed in the cultured monocytes after 10 days. The inclusions were considered to be those of E. bovis from their morphology, staining characteristics and growth characteristics in culture, and by indirect immunofluorescence examination with an anti-E. canis serum. The utility of peripheral blood monocyte cultures opens the possibility of diagnosing the carrier status of ehrlichiosis in animals.     

Role of monocyte recruitment in hemangiosarcoma metastasis in dogs

Canine hemangiosarcoma (HSA) is a highly malignant tumour associated with short survival times because of early and widespread metastasis. In humans and rodents, monocytes play key roles in promoting tumour metastasis through stimulating tumour cell extravasation, seeding, growth and angiogenesis. Therefore, we investigated the potential association between monocyte infiltration and tumour metastasis in HSA and other common canine tumours. Immunohistochemistry was used to quantify CD18⁺ monocytes within metastases. We found that HSA metastases had significantly greater numbers of CD18⁺ monocytes compared with metastases from other tumour types. HSA cells were the highest producers of the monocyte chemokine CCL2, and stimulated canine monocyte migration in a CCL2 dependent manner. These results are consistent with the hypothesis that overexpression of CCL2 and recruitment of large numbers of monocytes may explain in part the aggressive metastatic nature of canine HSA. Thus, therapies designed to block monocyte recruitment may be an effective adjuvant strategy for suppressing HSA metastasis in dogs.     

Inflammation-associated responses in piglets induced with post-weaning colibacillosis are influenced by dietary protein level

Forty piglets (average body weight = 5.32 kg) were used to investigate the effect of dietary crude protein (CP) content on immunological responses following a challenge with enterotoxigenic Escherichia coli (ETEC) K88. Pigs, housed 4 per pen, were randomly allotted to 2 diets: 1) a high, 225 g/kg CP diet (HCP) or 2) a low, 176 g/kg CP diet (LCP) supplemented with crystalline amino acids. Pigs were orally challenged with 6 mL of an ETEC K88 suspension containing 10¹⁰ cfu/mL on d 8 after weaning. Blood samples were collected from 10 pigs (1 pig/pen) on d 7 (at weaning), −24 h, 8 h, 72 h and 7 d after the challenge for determination of plasma urea N (PUN) and serum concentrations of tumor necrosis factor alpha (TNF-α) and interleukin 1 beta (IL-1β) and haptoglobin (Hp). Tumor necrosis factor alpha, IL-1β and Hp were measured as indicators of inflammatory responses. The concentrations of serum TNF-α at 8 h, 72 h and 7 d after challenge were similar to the level observed at 24 h before challenge but higher (P < 0.05) than the weaning level. Pigs fed the LCP diet had lower (P = 0.032) concentrations of IL-1β (72 vs. 116 pg/mL) at 8 h post-challenge compared with those fed the HCP diet. Likewise, pigs fed the LCP diet tended to have lower (P = 0.088) concentration of Hp (9 vs. 25 mg/dL) compared with those fed the HCP diet at 8 h post-challenge. Compared with the weaning concentration, PUN concentration at 72 h after ETEC challenge was higher (P < 0.05) in pigs fed the HCP diet. The results indicate that the LCP diet supplemented with crystalline amino acids reduced inflammatory responses, as indicated by serum IL-1β, in piglets infected with ETEC K88.     

Mononuclear phagocyte receptors in rhesus monkeys (Macaca mulatta) and their role in hemolytic disease of the newborn

Hemolytic disease of the newborn does not develop in rhesus monkeys because placentally-transferred maternal antibodies do not induce immune clearance of the newborn's erythrocytes. In an in vitro RBC adherence assay, rhesus peripheral blood monocytes did not bind newborn's RBC which had been coated in utero or in vitro with maternal antibodies. Nevertheless, rhesus phagocytes possess receptors that are specific for the Fc portion of IgC and for the C3b. Using purified human IgG subclasses as inhibitors of RBC adherence, rhesus Fc receptors preferentially bind IgG1 and IgG3. Thus, it may be that maternal antibodies are non-opsonic because they belong to IgG subclasses that do not bind effectively to rhesus Fc receptors. Also, RBC adherence appears to be controlled by the level of antibody coating which in turn is determined by avidity of the antibodies and by the number of RBC membrane determinants. The failure of maternal antibodies to opsonize the newborn's RBC and thus cause hemolytic disease is very likely due to the low avidity of antibodies and to the weak expression of blood group determinants on the membranes of these RBC.     

白藜芦醇抑制内毒素诱导小胶质细胞炎症因子表达

小胶质细胞释放的炎症介质对神经退行性疾病的发展有很重要的作用,白藜芦醇可抑制外周吞噬细胞生成和释放炎症介质。采用RT-PCR的方法在N9细胞株和原代小胶质细胞中检测了白藜芦醇对内毒素(LPS)诱导小胶质细胞肿瘤坏死因子α(TNF-α)和诱导型一氧化氮合成酶(iNOS)基因表达的影响。结果表明白藜芦醇在5~50μmol/L的浓度范围能显著的抑制TNF-α和iNOS的表达,白藜芦醇的上述抑制作用呈浓度依赖性。同时,白藜芦醇在N9细胞株中的抑制作用要稍强于原代小胶质细胞。     

Increased monocyte chemotactic protein-1 concentration and monocyte count independently associate with a poor prognosis in dogs with lymphoma

Overexpression of the chemokine monocyte chemotactic protein-1 (MCP-1) has been associated with a poor prognosis in many human cancers. Increased MCP-1 concentrations may promote tumour progression by increasing mobilization of myeloid derived suppressor cells such as immature monocytes and neutrophils. We hypothesized that increased numbers of peripheral neutrophils or monocytes and increased MCP-1 concentrations would predict a worse outcome in dogs with multicentric lymphoma. In this retrospective study involving 26 client-owned dogs diagnosed with lymphoma, we show that peripheral neutrophil and monocyte counts as well as serum MCP-1 concentrations were significantly elevated relative to healthy control animals, and that such increases were associated with a decreased disease-free interval in dogs treated with chemotherapy based on cyclophosphamide, vincristine, doxorubicin and prednisone (CHOP). To our knowledge, this is the first study showing that pretreatment evaluation of monocyte and neutrophil counts can provide important prognostic information in dogs with lymphoma. The mechanisms underlying these observations remain to be determined.     

沙门菌感染对小鼠白细胞总数及其亚群动态变化的影响

为研究沙门菌感染对小鼠白细胞总数及其亚群动态变化的影响,采取腹腔注射的方法给小鼠接种6.5×10⁹ CFU/mL浓度的沙门菌0.1 mL/只,分别在4、6、8、12、16和24 h采集小鼠血液,应用全自动动物血液细胞分析仪检测感染小鼠的白细胞总数、淋巴细胞数、单核细胞数和粒细胞数,记录并分析小鼠24 h内白细胞总数及其亚群的动态变化。结果表明：模型组小鼠白细胞总数及其亚群均呈先升高后降低的趋势,且白细胞总数和粒细胞数的变化幅度最明显,与空白对照组比较差异极显著（P<0.01）。说明感染沙门菌能够刺激小鼠机体产生免疫应答,影响血液中白细胞总数及其亚群的动态变化。