卵磷脂水解抑制试验测定家兔血清中的抗α毒素水平

以卵磷脂水解试验为基础 ,根据α毒素在被抗毒素完全中和后将出现水解抑制这一原理 ,建立了测定家兔血清抗α毒素水平的卵磷脂水解抑制试验方法。结果显示 ,卵磷脂水解抑制试验可用于测定不同血清样品的抗α毒素水平 ,抗血清完全中和单位剂量α毒素时 ,水解抑制试验结果明显。所能测定出的最小血清抗体量相当于中和 1/ 6 4MLD毒素的量 ,最适毒素中和时间为 30min ,其敏感性和精确性优于小鼠毒素中和试验 ,且操作简单 ,取材经济 。

抗α毒素单链抗体基因表达及生物学特性研究

将重组质粒分别转化至相应的受体菌XL1_BLUE中 ,得到重组菌株XL1_BLUE(pHOG_2E3)。ELISA和SDS_PAGE检测表明 :经IPTG诱导后所表达的ScFv目的蛋白在重组菌株XL1_BLUE(pHOG_2E3)中主要形成了包含体的形式 ,在其胞周质和培养上清中也检测到了ScFv的存在 ,经薄层扫描分析 :重组菌株XL1_BLUE(pHOG_2E3)的蛋白表达产物分别占菌体可溶性蛋白的 4% ,占菌体总蛋白的相对含量为 2 2 % ,其相对分子量约为 31kD。表达的ScFv蛋白不但具有中和卵磷脂酶的活性 ,而且能够对致死性腹腔攻击浕毒素的小鼠产生了良好的被动?

Physicochemical Characters of rPoIFN-α and Its Antiviral Activity in vitro

[Objective]The research aimed to test and identify the physicochemical characters and antiviral activity in vitro of semi-finished product of the recombinant porcine rPoIFN-α. [Method]HEp-2/VSV system was used to test the antiviral activity of three batches of rPoIFN-α. Using recombinant human IFN-α as reference,the titer of interferon was measured. The semi-finished product of rPoIFN-α with the known titer were treated with 0.25% trypsin,HCl and mouse anti-porcine IFN-α monoclonal antibody. And the anti-viral activity of each batch of rPoIFN-α was detected. The physicochemical characters of rPoIFN-α were evaluated. The inhibition of induced cytopathic effect of rPoIFN-α on PPV （Porcine parvovirus） and PRV （Porcine pseudorabies） on swine kidney cell （PK-15） was determined. And the antiviral activity of rPoIFN-α in vitro was observed. [Result]The titers of semi-finished products of rPoIFN-α titrated by HEp-2/VSV system could reach 1.5×105 IU/ml,with the specific activity of 1.1×106 IU/mg. The residual rate of the tier of rPoIFN-α treated by 0.25% trypsin at 37 ℃ for 1 h was less than 1%. And that treated with HCl （pH of 2.0） for 72 h was up to 95%. And that treated at 56 ℃ for 30 min and that treated by mouse anti-porcine IFN-α monoclonal antibody at 37 ℃ for 1 h were higher than 47% and about 1% respectively. The antiviral test in vitro showed that 50 and 500 IU/ml rPoIFN-α could inhibit the induced cytopathic effect of PRV and PPV on PK-15 cell lines. [Conclusion]rPoIFN-α had the basic physicochemical characters of IFN-α. And it could inhibit the induced cytopathic effect of PRV and PPV on PK-15 cell lines,but there was dosage difference.

Effect of interferon in combination with ribavirin on the plus and minus strands of HCV RNA in patients with chronic hepatitis C

AIMS To probe the effect of interferon in combination with rib- avirin on the plus and minus strands of hepatitis C virus RNA (HCV RNA). METHODS Twenty-three cases diagnosed as chronic hepatitis C (CHC) according to positive HCV RNA/anti-HCV,fluctuating levels of aminotransferase activities (>1 year) and absence of other hepatitis virus marker,were studied. Among them,13 pa- tients received combined antiviral therapy (subcutaneous injection of 3MU of interferon-α three times per week for 3 months and intra- venous drip of 1 g of ribavirin per day during the first month of treatment with interferon) and 10 patients received single interfer- on therapy (the same as above-mentioned) as control. The plus and minus strands of HCV RNA in sera and peripheral blood mononuclear cells (PBMCs) of these patients were tested by means of nested reverse transcription-polymerase chain reaction (nested RT-PCR). RESULTS At the end of therapy,the abnormal ALT levels de- creased to normal range in 9 (69.23%) cases in the combined antiviral group. Of them,5 (55.56%)experienced post-therapy relapse and 4 (44.44%) were complete responders. In the inter- feron group,the ALT decreased to normal in 6 (60%) cases,of which,4 (66.67%) had post-therapy relapse and 2 (33.33%) were complete responders. The differences between the two groups were nonsignificant (P>0.05). At the end of therapy,the positive rate of the plus strand in sera decreased from 92.3% to 38.46% (P<0.05) and that of the minus strand in PBMCs,from 76.92% to 38.46% (P<0.05) in the combined antiviral group; and in the interferon group,the former decreased from 100% to 50% (P<0.05) and the latter,from 90% to 40% (P<0.05). Again,no significant differences were found between groups (P >0.05). The relapse occurred in patients whose plus strand HCV RNA in PBMCs remained positive before and after treatment. CONCLUSIONS Ribavirin could not enhance the antiviral effect of interferon. The absence of HCV RNA in serum does not mean complete clearance of HCV,and its value for evaluating the an- tiviral effect and prognosis is limited. Therefore,it is essential to measure the plus and minus strands of HCV RNA in sera and PBM- Cs simultaneously.

Characterization of the antiviral effects of interferon-α against a SARS-like coronoavirus infection in vitro

Interferon （IFN）-αs bind to and activate their cognate cell surface receptor to invoke an antiviral response in target cells. Well-described receptor-mediated signaling events result in transcriptional regulation of IFN sensitive genes, effectors of this antiviral response. Results from a pilot study to evaluate the clinical efficacy of IFN-α treatment of SARS patients provided evidence for IFN-inducible resolution of disease. In this report we examined the contribution of IFN-inducible phosphorylation-activation of specific signaling effectors to protection from infection by a SARS-related murine coronavirus, MHV-1. As anticipated, the earliest receptor-activation event, Jakl phosphorylation, is critical for IFN-inducible protection from MHV-1 infection. Additionally, we provide evidence for the contribution of two kinases, the MAP kinase p38MAPK, and protein kinase C （PKC） 5 to antiviral protection from MHV-1 infection. Notably, our data suggest that MHV^I infection, as for the Urbani SARS coronoavirus, inhibits an IFN response, inferred from the lack of activation ofpkr and 2 ＇5 ＇-oas, genes associated with mediating the antiviral activities of IFN-as. To identify potential target genes that are activated downstream of the IFN-inducible signaling effectors we identified, and that mediate protection from coronavirus infection, we examined the gene expression profiles in the peripheral blood mononuclear cells of SARS patients who received IFN treatment. A subset of differentially regulated genes were distinguished with functional properties associated with antimicrobial activities.

New therapeutic vaccination strategies for the treatment of chronic hepatitis B

Chronic hepatitis B virus(CHB) is currently treated with either interferon-based or nucleot(s)idebased antiviral therapies.However,treatment with pegylated interferon alpha results in a durable antiviral response in only about 30%patients and is associated with side effects.Most patients receiving nucleot(s)ide analogue treatment do not establish long-term,durable control of Infection and have rebounding viremia after cessation of therapy.Thus,novel therapy strategies are necessary to achieve the induction of potent and durable antiviral immune responses of the patients which can maintain long-term control of viral replication.Therapeutic vaccination of HBV carriers is a promising strategy for the control of hepatitis B.Here the authors review new therapeutic vaccination strategies to treat chronic hepatitis B which may be introduced for patient treatment in the future.

Alpha 1-antitrypsin and alpha 1-acid glycoprotein reduce the sensitivity of human dermal fibroblast to endotoxin

Objective: To test the hypothesis that acute phase reactants, such as alpha 1-antitrypsin and alpha 1-acid glycoprotein, could protect mammalian cells from further damage. Methods: Human dermal fibroblasts (5×10 4) were cultured with DMEM plus 10% FBS at 37℃ in a 5% CO 2 incubator. Different doses of LPS (lipopolysaccharide) and/or acute phase reactants were added. After 24 hours, the cultured supernatant was aspirated, the cells were washed, fixed and stained by methylene blue. The unbound stain was washed off. The stained cells were solubilized in 0.1 ml of 1% Triton X-100. The absorbance of each well was measured using an ELISA spectrophotometer. The concentration of LPS which decreased the absorbance to 70% of the control (LPS-free) cultures was defined as LD 30. Results: In order to achieve LD 30 in the presence of acute phase proteins, it was necessary to alter the LPS concentrations. The LD 30 of LPS treated with 0, 0.5, 2, 10 mg/ml antitrypsin and 0, 0.5, 2, 10 mg/ml glycoprotein was 5.4, 6.5, 7.6, 14.2 mg/ml and 5.2, 5.9, 6.9, 10.5 mg/ml, respectively. Statistically, with the treatment of more than 2 mg/ml antitrypsin or glycoprotein, LD 30 increased significantly. Conclusions: Our data show that fibroblasts are susceptible to the direct toxicity of LPS. Alpha 1-antitrypsin and alpha 1-acid glycoprotein can reduce the toxicity and/or increase the tolerance of mammalian cells to LPS.