人精液源性病毒感染增强因子研究进展

人精液前列腺酸性磷酸酶（prostatic acid phosphatase, PAP）多肽片段形成的淀粉样原纤维具有促进人类免疫缺陷病毒（human immunodeficiency virus, HIV）感染的作用，这些原纤维被称为精液源性病毒感染增强因子（semen-derived enhancer of viral infection, SEVI），其中PAP第248—286位多肽片段（PAP248-286）促进HIV感染的作用最强。具有阳离子特性的SEVI可通过静电作用捕获HIV颗粒而促进HIV感染。近期研究报道，SEVI对异嗜性小鼠白血病病毒相关病毒感染也有增强作用，可能与前列腺癌发生有关。某些多聚阴离子化合物和绿茶多酚成分能明显抑制SEVI活性。研究SEVI生物学特性及其功能对于HIV等病毒感染的防治具有重要意义。

对中小养猪场非洲猪瘟防控措施的具体应用探讨

作为我国养殖行业的支撑之一,中小养猪场的经营及发展状况可对整合行业产生一定的影响。基于此,本文主要针对中小养猪场养殖管理的特殊性进行分析;并提出运用建立生物隔离屏障措施、借鉴成功防控经验措施、管控病毒感染源及传播途径措施,改善中小养猪场的非洲猪瘟防控效果,以期为中小养猪场的安全管理工作提供必要的理论支持,减少其经济损失。

Identification of a novel C-type lectin from the shrimp Litopenaeus vannamei and its role in defense against pathogens infection

Acting as one of the pattern recognition receptors （PRRs）, C-type lectin is believed to mediate pathogen recognition and plays an important role in the clearance of pathogens as part of the innate immune system. In this work, a novel C-type lectin gene （named LvLecl） was cloned from the shrimp Litopenaeus vannamei, The ORF of LvLecl is 510 bp, encoding 169 amino acids. The deduced amino acid sequence contains a putative signal peptide of 19 amino acids at the N-terminal and a carbohydrate recognition domain （CRD） at the C-terminal. LvLecl was mainly expressed in the hepatopancreas. Real-time PCR analysis indicated that the level of LvLecl transcripts significantly changed in the hepatopancreas after the shrimp were artificially challenged with LPS, Micrococcus lysodeikticus and white spot syndrome virus （WSSV）. RNAi-based silencing of LvLecl resulted in increases in mortality when the shrimp were challenged with WSSV, and the median lethal time was reduced compared with controls. Although there was no characteristic ＂EPN＂ （Glu-Pro-Ser） or ＂QPD＂ （Gin-Pro-Asp） motif, the recombinant LvLecl, expressed in Escherichia coli BL21 （DE3）, could also agglutinate M. lysodeikticus and Vibrio anguillarum. The agglutinating activities were calcium-dependent and could be inhibited by D-mannose, D-glucose, D-galactose and N-Acetyl-D-mannose. These results suggest that LvLecl might be involved in the immune response against WSSV and bacterial infections and contribute to non-self recognition as a pattern recognition receptor in the innate immune system of the shrimp L. vannamei.

Study of human B7 homolog 1 expression in patients with hepatitis B virus infection

AIM: To further investigate the role of human B7 homolog 1 (B7-H1) in the mechanism of persistent hepatitis B virus (HBV) infection. METHODS: Peripheral and intra-hepatic B7-H1 expression were compared by flow cytometry and immunochemical staining between two 2 distinct groups, one being chronic HBV tolerance patients (CHB-T) and the other being acute hepatitis B patients (AHB). B7-H1 mRNA expression level was also compared by real time polymerase chain reaction between CHB-T and AHB patients. The location of intra-hepatic B7-H1 and CD40 expression were analyzed by immunofluorescence. The levels of B7-H1 and CD40 expression on cultured myeloid dendritic cells (mDCs) with or without hepatitis B surface antigen (HBsAg) treatment were analyzed dynamically by flow cytometry. Intracellular interferon-γ (IFN-γ) staining and the stimulatory capacity of mDC of cultured mDC with or without HBsAg treatment were also compared by flow cytometry. RESULTS: Peripheral B7-H1 expression on mDCs was increased significantly in AHB compared to CHB-T patients (P < 0.05). In the liver tissues from CHB-T patients, B7-H1 positive cells were almost absent despite a persistently elevated serum HBsAg load. In contrast, there were indeed increased B7-H1-positive cells in situ in the liver tissue from AHB. In vitro analysis showed the parallel upregulation of B7-H1 and CD40 on CD11c+ mDCs after the onset of stimulation. Addition of recombinant hepatitis B surface antigen (rHBsAg) significantly decreased CD40 expression (P < 0.05 at 16 h, 20 h and 24 h time points). B7-H1 expression was also inhibited by rHBsAg, and the inhibition rate of CD40 was greater than that of B7-H1. This preferential inhibition of CD40 expression on mDCs by rHBsAg resulted in the dysfunction of mDCs and T cells in the mixed leucocyte reaction (MLR) system. With rHBsAg pretreatment, in a carboxyfluorescein diacetate succinimidyl ester (CFSE) labeled MLR system at a ratio of 1:5 responder cell-stimulator cell (R/S), the CFSE dim percentage of T cells decreased from 85.1% to 25.4% and decreased from 30.3% to 12.0% at 1:10 R/S. IFN-γ production by CD8+ T cells, in the MLR system, was reduced significantly by HBsAg pretreatment. At ratios of 1:5 R/S, the percentage of IFN-γ and CD8 dual positive T cells decreased from 55.2% ± 5.3% to 15.1% ±3.1% (P < 0.001), and decreased from 35.0% ± 5.1% to 7.3% ± 2.7% at ratios of 1:10 R/S (P < 0.001). CONCLUSION: B7-H1 is not a signature of immune dysfunction, but an inflammation marker. HBsAg regulate immune response by tipping the balance between B7-H1 and CD40.

精液源性多肽促HIV感染及相关拮抗物的研究进展

性行为是目前艾滋病病毒(HIV)传播的主要途径,超过80%的新发HIV感染是通过性传播。精液不仅是HIV的载体,而且含有能增强HIV感染的多肽。体外实验证明,精液中的前列腺磷酸酶多肽成分(PAP248-286、PAP85-120)能和精囊蛋白(SEM1、SEM2)的多肽片段形成淀粉样原纤维,显著促进HIV感染。这些精液源性多肽利用其独特的cross-β淀粉样原纤维结构和富含阳离子的表面电荷,在病毒和靶细胞间形成阳离子桥(cationic bridge),促进病毒结合靶细胞,从而增强HIV感染。因此,研究人员目前正在研发多种以精液源性多肽为靶点的药物,用于预防HIV性传播。这些药物包括阴离子聚合物、绿茶提取物(EGCG)、苯并噻唑苯胺(BTA)等。体外实验证明,这些药物能抵消精液源性多肽介导的促HIV感染的作用。文章描述了有关精液源性多肽促进HIV感染的研究,以及相关拮抗物的研发工作。

Effect of Maternal Antibodies on the Pathogenesis of Avian Reovirus Infections in Broiler Chickens Using Real-Time Reverse Transcriptase Polymerase Chain Reaction

The effect of maternal antibodies on the pathogenesis of avian reovirus （ARV） was studied in commercial and specific pathogen free broilers （SPF） using a real-time reverse transcriptase （RT）-polymerase chain reaction （PCR） assay, along with the incidence and severity of morbidity, mortality, and gross lesions. ARV RNA was detected in cloacal swabs in both bird groups from the first day throughout the 21 days experiment. Commercial broiler chickens, which had high maternal antibodies against ARV, showed minimum clinical signs, gross lesions, and lower numbers of birds with viral RNA excretion, whereas specific pathogen free （SPF） broiler chickens, which did not have antibody against ARVs, had 30% mortality, more severe signs, and higher numbers of birds excreting viral RNA. The highest peak of SPF birds excreting viral RNA occurred during the time of maximum mortality. The protective effect of maternal antibody on ARV pathogenesis in broiler chickens correlated with the detection of ARV RNA using the real-time RT-PCR.

Severe human infection with a novel avian-origin influenza A(H7N4) virus

Human infections with influenza H7 subtypes, such as H7Ng, have raised concerns worldwide. Here, we report a human infection with a novel influenza A（HTN4） virus. A 68 years-old woman with cardiovascular and cholecystic comorbidities developed rapidly progressed pneumonia with influenza-like-illness as initial symptom, recovered after 23 days-hospitalization including 8 days in ICLI. Laboratory indicators for liver and blood coagulation dysfunction were observed. Oseltamivir phosphate, glucocorticoids and antibiotics were jointly implemented, with nasal catheterization of oxygen inhalation for this patient. We obtained the medical records and collected serial respiratory and blood specimens from her. We col- lected throat, cloacal and/or feces samples of poultry and wild birds from the patient＇s backyard, neigh- borhood, local live poultry markets （LPMs） and the nearest lake. All close contacts of the patient were followed up and sampled with throat swabs and sera. Influenza viruses and other respiratory pathogens were tested by real-time RT-PCR, viral culturing and/or sequencing for human respiratory and bird sam- ples. Micro-neutralizing assay was performed for sera. A novel reassortant wild bird-origin H7N4 virus is identified from the patient and her backyard poultry （chickens and ducks） by sequencing, which is dis- tinct from previously-reported avian H7N4 and H7N9 viruses. At least four folds increase of neutralizing antibodies to H7N4 was detected in her convalescent sera. No samples from close contacts, wild birds or other poultry were tested positive for H7N4 by real-time RT-PCR.

Environmental connections of novel avian-origin H7N9 influenza virus infection and virus adaptation to the human

A novel H7N9 influenza A virus has been discovered as the causative identity of the emerging acute respiratory infection cases in Shanghai,China.This virus has also been identified in cases of infection in the neighboring area Hangzhou City in Zhejiang Province.In this study,epidemiologic,clinical,and virological data from three patients in Hangzhou who were confirmed to be infected by the novel H7N9 influenza A virus were collected and analyzed.Human respiratory specimens and chicken feces from a contacted free market were tested for influenza virus by real-time reverse transcription PCR(RT-PCR) and sequencing.The clinical features of the three cases were similar featured with high fever and severe respiratory symptoms;however,only one of the patients died.A certain degree of diversity was observed among the three Hangzhou viruses sequenced from human samples compared with other reported H7N9 influenza A viruses.The sequences of the novel avian-origin H7N9 influenza viruses from Hangzhou City contained important amino acid substitutions related to human adaptation.One of the Hangzhou viruses had gained a novel amino acid substitution(Q226I) in the receptor binding region of hemagglutinin.More importantly,the virus sequenced from the chicken feces had a 627E substitution in the PB2 protein instead of the mammalian-adapted 627K substitution that was found in the PB2 proteins from the Hangzhou viruses from the three patients.Therefore,the newly-emerging H7N9 virus might be under adaptation pressure that will help it "jump" from avian to human hosts.The significance of these substitutions needs further exploration,with both laboratory experiments and extensive field surveillance.