重组牛白细胞介素—2生物活性单位的测定及其理化性质的分析

本研究对大肠杆菌表达的重组牛白细胞介素－２的生物活性单位进行了测定,以已标定的人白细胞介素－２为标准品,ＭＴＴ比色法测出重组牛白细胞介素－２的生物活性单位约为４×１０＾５ｕ／Ｌ菌液。同时,以ＳＤＳ－ＰＡＧＥ法测出表达的重组牛白细胞介素－２分子量约为１５．５ＫＤ,理化性质分析结果表明,重组牛白细胞介素－２生物活性酸碱适应范围为２～１０,对胰蛋白酶和木瓜蛋白酶的作用敏感,而对核酸酶的作用则不敏感,重组     

重组牛白细胞介素-2生物活性单位的测定及其理化性质的分析

本研究对大肠杆菌表达的重组牛白细胞介素－２的生物活性单位进行了测定。以已标定的人白细胞介素－２为标准品，ＭＴＴ比色法测出重组牛白细胞介素－２的生物活性单位约为４×１０６ｕ／Ｌ菌液。同时，以ＳＤＳ－ＰＡＧＥ法测出表达的重组牛白细胞介素－２分子量约为１５．５ＫＤ。理化性质分析结果表明，重组牛白细胞介素－２生物活性酸碱适应范围约为２～１０；对胰蛋白酶和木瓜蛋白酶的作用敏感，而对核酸酶的作用则不敏感；重组牛白细胞介素－２对温度变化敏感，表现为不耐高温。     

雏鸡人工感染马立克氏病强毒后白细胞介素2及其受体的变化

１日龄雏鸡人工感染马立克氏病强毒后，脾脏Ｔ淋巴细胞白细胞介素２诱生活性比健康对照雏鸡显著降低，胸腺Ｔ淋巴细胞ＩＬ－２诱生活性虽见降低但无统计学显著性差异。脾脏和胸腺Ｔ淋巴细胞白细胞介素２受体诱导表达显著减少。     

重组鸡白细胞介素-2对球虫感染雏鸡细胞免疫的影响

本实验旨在研究重组鸡白细胞介素－２对球虫感染雏鸡细胞免疫的影响。实验采用１４日龄伊莎蛋鸡２１０只，分为７组，其中一组为不感染对照组，三组为柔嫩艾美耳球虫感染组，卵囊感染剂量分别为１万／只、２万／只、５万／只，另外三组在感染卵囊１万／只、２万／只、５万／只的同时，肌注真核细胞表达的重组鸡白细胞介素－２ ０．４ｍｌ／只。感染后第０、４、６、９、１４、１８、２３、２８天剖杀取牌和盲肠扁桃体，分离淋巴细胞，分别用ＣｏｎＡ和ＰＨＡ刺激，采用ＮＩＴ比色法进行淋巴细胞转化试验，结果表明：在球虫感染后第４天（裂殖生殖阶段）和第６天（卵囊形成阶段），感染组脾和盲肠扁桃体淋巴细胞转化率均低于对照组，加重组鸡白细胞介素－２组脾和盲肠扁桃体淋巴细胞转化率高于感染组，相当或高于对照组水平。在感染后第９天和第１４天（恢复期）加重组鸡白细胞介素－２组脾淋巴细胞转化率高于对照组，加重组鸡白细胞介素－２组盲肠扁桃体淋巴细胞转化率相当于对照组。本实验结果说明：１．球虫感染可以抑制细胞免疫；２．加重组鸡白细胞介素－２可以克服球虫感染引起的免疫抑制。     

鸡T淋巴细胞IL－2的体外诱生及活性检测

经Ｌ１６（４５）正交试验选择，并经实验验证，鸡脾脏Ｔ淋巴细胞白细胞介素２（ＩＬ－２）体外诱生和活性检测的最优水平组合及适宜条件为２．５μｇ／ｍＬ伴刀豆蛋白Ａ（ＣｏｎＡ）、ＩＬ－２体外诱生时间２０ｈ、１×１０７／ｍＬ淋巴细胞、１０％小牛血清、靶细胞培养时间４８ｈ、４×１０６／ｍＬ靶细胞、靶细胞接触时间３６ｈ、５ｍｇ／ｍＬＭＴＴ、ＭＴＴ加入时间３ｈ和甲溶解时间２ｈ；胸腺Ｔ淋巴细胞ＩＬ－２体外诱生和活性检测的最优水平组合及适宜条件为５μｇ／ｍＬＣｏｎＡ、ＩＬ－２体外诱生时间４８ｈ，余同脾脏Ｔ淋巴细胞ＩＬ－２体外诱生及活性检测。比较试验表明，ＭＴＴ比色分析法和３Ｈ－胸腺嘧啶核苷（３Ｈ－ＴｄＲ）掺入法有显著的直线回归关系。     

重组牛白细胞介素-2增强小鼠对伊氏锥虫可溶性抗原免疫应答的研究

使用伊氏锥虫可溶性抗原免疫小鼠，研究了同时注射重组牛白细胞介素－２（ｒＢＩＬ－２）对ＮＫ细胞杀伤活性及特异性抗体水平的影响。试验鼠随机分为４组：Ａｇ组，ｒＢＩＬ－２组，Ａｇ＋ｒＢＩＬ－２组和ＰＢＳ对照组。以ＬＤＨ释放法和间接ＥＬＩＳＡ法分别检测脾ＮＫ细胞杀伤活性及抗体水平。结果表明，首次免疫后２４ｄ，Ａｇ组ＮＫ细胞杀伤活性为３１．６％，ｒＢＩＬ－２组为９９．６６％，Ａｇ＋ｒＢＩＬ－２组为９８．９８％，对照组为１９．７３％；抗体效价Ａｇ组为２４，Ａｇ＋ｒＢＩＬ－２组为２６。说明ｒＢＩＬ－２可显著提高ＮＫ细胞杀伤活性及促进抗体生成，提高宿主免疫力。     

鸡IL—2基因的克隆及序列测定

根据已发表的鸡白细胞介素－２（ＩＬ－２）基因序列设计引物,用ＲＴ－ＰＣＲ方法从新翅疫病毒感染的雏鸡脾淋巴细胞培养物中扩增出鸡的ＩＬ－２基因ｃＤＮＡ,并进行序列测定,为进一步表达鸡ＩＬ－２并深入研究其功能奠定了基础。     

鸡T淋巴细胞IL—2的体外诱生及活性检测

经Ｌ１６正交试验选择，并经实验验证，鸡脾脏Ｔ淋巴细胞白细胞介素２（ＩＬ－２）体外诱生和活性检测的最优水平组合及适宜条件的２．５μｇ／ｍＬ伴刀豆蛋白Ａ，ＩＬ－２体外诱生时间２０ｈ，１×１０＾７／ｍＬ淋巴细胞、１０％小牛血清、靶细胞培养时间４８ｈ，４×１０＾６／ｍＬ靶细胞，靶细胞接触时间３６ｈ，５ｍｇ／ｍＬＭＴＴ，ＭＴＴ加入时间３ｈ和甲替溶解时间２ｈ；胸腺Ｔ淋巴细胞ＩＬ－２体外诱生和活性检测的最优水平     

白细胞介素—3对猪瘟病毒E2基因疫苗免疫增强作用的研究

以昆明系小白鼠为试验动物，观察了白细胞介素－３（ＩＬ－３）对猪瘟病毒Ｅ２囊膜糖蛋白（ＨＣＶ Ｅ２）基因疫苗免疫效果的增强作用。用ＤＮＡ重组技术将ＨＣＶ Ｅ２基因和白小鼠ＩＬ－３基因克隆到ｐＩＲＥＳ１ｎｅｏ质粒，因在两者之间有脑心肌炎病毒（ＥＭＣＶ）的核糖体进入位点（ＩＲＥＳ）片段，可得到ＨＣＶ Ｅ２抗体效价。结果显示，ＩＬ－３能显著提高ＨＣＶ Ｅ２基因疫苗的免疫效果，表明ＩＬ－３可作为ＨＣＶ Ｅ２     

鸡IL-2基因的克隆及序列测定

应用逆转录多聚酶链反应（ＲＴ－ＰＣＲ）技术，参照Ｓｕｎｄｉｃｋ发表的鸡白细胞介素２（ＩＬ－２）ｃＤＮＡ基因序列，利用在行设计合成的１对引物，从ＣｏｎＡ活化的５周龄ＨＷＬ－ＳＰＦ鸡脾细胞中，扩增出长４４５ｂｐ的鸡ＩＬ－２ｃＤＮＡ基因，以ＰＵＣ１１９为载体，克隆了扩增片段，经酶切鉴定及ＤＮＡ序列测定，确认为鸡ＩＬ－２基因，该序列与Ｓｕｎｄｉｃｋ报道的结果一致。对氨基酸的比较发现，鸡ＩＬ－２与牛ＩＬ－２     

Cloning and expression of bovine and porcine interleukin-2 in baculovirus and analysis of species cross-reactivity

The cDNAs encoding bovine and porcine interleukin-2 (IL-2) have been expressed using the baculovirus Autographa californica nuclear polyhedrosis virus as a vector in insect cells. Insect cells infected with recombinant viruses secreted bovine and porcine IL-2 into the culture medium, with biological activities for maintaining the proliferation of homologous cells. When the activities of these two IL-2 proteins and commercially available human IL-2 were tested on heterologous cells differences were found. Recombinant bovine (rb)IL-2 only supported the growth of bovine lymphocytes and was not active on human, mouse or porcine lymphocytes. Recombinant porcine (rp)IL-2 and recombinant human (rh)IL-2 supported the proliferation of human, bovine, porcine and murine cells. However, the proliferative response of human lymphocytes to rpIL-2 was only 50% of that seen with rhIL-2. Sequence differences at the predicted p55 and p75 contact binding sites may explain this.     

Cervine T-lymphocyte growth factors and their measurement in tuberculosis

Research into the composition and function of the immune response in domesticated ruminants has tended to focus on the ovine and bovine systems. With the recent domestication of deer, health problems have developed which require a fundamental knowledge of the immune function in exotic ruminants. In this report it is shown that although recombinant human and mouse interleukin-2 (IL-2) were capable of stimulating cervine T-cell proliferation, optimal proliferation was only achieved using recombinant bovine IL-2. While some phylogenetic restriction of IL-2 cross-reactivity was found, in some cases this could be overcome by using high concentrations of recombinant IL-2. Using cervine T-cell blasts it was possible to assay in vitro T-cell growth factor (TCGF) production by lymphocytes isolated from deer naturally exposed to tuberculosis Mycobacterium bovis). Differences were found in the amount of TCGF present in the supernatants of antigen-activated cells isolated from severely diseased animals, those with limited disease and non-diseased animals.     

Preparation, purification and characterization of bovine Peyer''s patch leukocytes.

An enzymatic technique for isolating bovine Peyer's patch leukocytes was developed. Enzymatic dissociation of Peyer's patches yielded a cell population rich in T and B lymphocytes containing 6-10% adherent accessory cells, as defined by morphology and nonspecific esterase staining. Analysis of Peyer's patch lymphocytes, using sheep erythrocyte rosetting and immunofluorescence with conventional antisera and monoclonal antibodies, showed that leukocytes were approximately 45% T cells and 25% Ig-positive B cells. The cell population contained functionally active T and B lymphocytes which proliferated in response to T and B cell mitogens and to exogenous human recombinant interleukin-2. The observed differences in patterns of Peyer's patch leukocyte responsiveness to these mitogens suggest some cellular heterogeneity of the bovine Peyer's patch.     

Immunomodulation: a means of disease prevention in stressed livestock

The ability to stimulate the immune response of cattle and pigs offers a new means of disease intervention. This review discusses current in vivo experiments that have evaluated immunomodulators in cattle and pigs. Levamisole, thiabendazole, imuthiol, avridine, isoprinosine, bovine recombinant interferon, human recombinant interleukin-2, bovine recombinant interleukin-2 and various supplemental vitamins and minerals have been used as immunomodulators in livestock with various degrees of success. Future research on immunomodulators, specific for domestic farm animals, will provide additional methods of treating immunosuppressed animals.     

Isolation, characterization and in vitro mitogenic stimulation of peripheral blood lymphocytes from an American buffalo.

A rapid and reproducible method is described for the isolation and characterization of leukocytes from the peripheral blood of an American buffalo (bison). Centrifugation of the buffy coat cells on a Percoll gradient (1.079 g/mL) at 650 x g for 20 min resulted in the separation and high yields of pure viable leukocytes. The sheep erythrocyte-rosetting technique (ER) showed that 59% of the cells were ER+ (T lymphocytes). Fluorescein isothiocyanate (FITC)-conjugated peanut agglutinin and FITC-conjugated concanavalin A revealed 77% and 89% positive cells, respectively. The isolated leukocytes contained adherent accessory cells and functionally active T and B lymphocytes which proliferated in response to both T and B cell mitogens and to exogenous recombinant bovine interleukin-2 in the absence and/or presence of the thiol compound 2-mercaptoethanol.     

In vitro interactions of cytokines and bovine viral diarrhea virus in phytohemagglutinin-stimulated bovine mononuclear cells

Bovine viral diarrhea (BVD) virus inhibited phytohemagglutinin (PHA)-stimulated bovine peripheral blood mononuclear cell (PBMC) proliferation and bovine interleukin-2 (IL-2) production. In the controls, the heat-inactivated BVD virus was not capable of suppressing the PHA-stimulated PBMC proliferation. Presence of exogenous cytokines, such as purified human IL-2, recombinant bovine interleukin-1 (rbovIL-1), recombinant bovine IL-2, and recombinant human IL-6 failed to reverse the BVD virus-induced immunosuppression. Also, we found that the BVD virus inhibited PHA and IL-2 induced proliferation of bovine PBMC in the early and late stages of activation. In summary, our data suggest that BVD virus induced immunosuppression was not due to destruction of the PBMC but may be inhibiting one or more of the important intracellular enzymes that may regulate PBMC proliferation.     

Cloning,expression, and tissue distribution of bovine interleukin-21

Bovine interleukin-21 (IL-21) cDNA was cloned and sequenced from bovine peripheral blood lymphocytes (PBLs) stimulated with 10 microg/ml concanavalin A (ConA), 10 microg/ml phytohemagglutinin (PHA), and 50 ng/ml phorbol 12-myristate 13-acetate (PMA) for 48 h. The open reading frame of the bovine IL-21 cDNA is 459 bp in length and encodes 152 amino acids. The predicted amino acid sequence is 78.2 and 58.5% homologous to the human and murine IL-21 amino acid sequences, respectively. Recombinant bovine IL-21 was expressed by a baculovirus expression system. The bovine IL-21 was processed to the mature form in insect cells and secreted to the supernatant confirmed by N-terminal amino acid sequencing. The recombinant bovine mature IL-21 induced the proliferation of human IL-2-dependent cells, ILT-MAT. The mRNA expression for bovine IL-21 was observed in the spleen, but not in the brain, heart, lung, liver, and kidney. The bovine IL-21 identified in this study may provide new methods for the enhancement of innate immunity in cows.     

Replication of bovine respiratory syncytial virus in bovine and ovine peripheral blood lymphocytes and monocytes and monocytic cell lines

The present study compared the replication of bovine respiratory syncytial virus (BRSV) in bovine and ovine peripheral blood mononuclear cells, ovine and bovine monocytic cell lines and ovine alveolar macrophages. Low titres of virus were detected in ovine and bovine lymphocytes and monocytes 24–96 h post-exposure to the virus but there was no apparent replication of the virus in ovine alveolar macrophages during the culture period. The virus replicated to higher but statistically insignificant titres in ovine and bovine peripheral blood monocytes than in lymphocytes, with lymphocytes yielding peak titres significantly earlier. The secondary cell lines obtained from ovine liver and bone marrow also supported the replication of BRSV to high titres. The titres of BRSV in ovine and bovine lymphocytes and monocytes were significantly lower than in secondary cell lines. The addition of human recombinant tumour necrosis factor alpha after exposure to the virus or pre-incubation of ovine or bovine monocytic cells with either human recombinant interleukin 2 or phorbol myristate acetate before exposure to BRSV, did not significantly affect virus titre. Pre-incubation of cells with indomethacin or actinomycin significantly lowered virus titre (p<0.05).     

Identification of positive cells to interleukin-4 in bovine haemal nodes

The bovine haemal nodes are lymphatic organs located in the haemal circulation. Their parenchyma is represented by plasma cells, macrophages and B and T lymphocytes. The T helper type 2 (Th2) CD4 lymphocyte can be found within the T lymphocytes. The activated Th2 CD4 lymphocyte produces interleukin-4 (IL-4), a peptidic hormone involved in the acute-phase immune response. This interleukin can promote either B-lymphocyte differentiation and T-lymphocyte proliferation or it can promote the type of immunoglobulin that can be liberated. Our results have shown, by immunostaining with anti-IL-4, not only the presence and localization of these lymphocytes in bovine haemal nodes but also the participation of polymorphonuclear cells (neutrophils) in the storage of IL-4. These results give value to the humoral and cellular immunological importance of haemal nodes in bovines and they can serve as a contribution to determine the cross-reactivity of bovine IL-4 with the human anti-serum used in this work.