江西省表观健康猪群携带猪链球菌状况分析

目的：了解江西省表观健康猪群携带猪链球菌的情况,为有效防控猪链球菌病提供科学依据。方法选取景德镇市、崇仁县为采样点,采集表观健康猪群鼻咽拭子和扁桃体进行猪链球菌病原分离鉴定。结果共采集表观健康猪群鼻咽拭子和扁桃体样本301份,检出2株猪链球菌2型,其毒力基因mrp、sly、ef均为阴性。结论本次调查中江西省表观健康猪携带猪链球菌的带菌率为0.66％。     

经球囊导管肝段热凝固CT与病理对照研究

目的观察经球囊导管阻断肝动脉高热灌注生理盐水行肝段热凝固CT表现。方法实验猪6头,选用球囊导管阻断肝段动脉血流进行热灌注,导管流出温度设置50~60℃之间。热灌注结束后即刻、14天,行肝动脉DSA检查和肝脏螺旋CT扫描,14天将实验猪全部处死,取出肝脏进行病理检查。结果热灌注后14天,6头实验猪均存活。DSA检查见靶段动脉闭塞,肝组织热灌注区显示充盈缺损。肝脏热灌注区CT影像学表现:热灌注结束后即刻,热灌注区显示大片状低密度改变,无明显强化,边缘显示模糊;热灌注后14天,CT平扫示肝脏热灌注区呈典型楔形低密度改变;CT增强示热灌注区显示"三环征",由内向外分为低密度无增强区、边缘强化带和移行区透明带。病理上取得6个热凝固灶,CT上低密度无增强区、边缘强化带和移行区透明带分别代表病理的凝固性坏死区、炎性充血带和纤维化带。结论增强CT能准确反映经动脉导管肝段介入性热毁损的病理改变,DSA价值有限。     

豚鼠主动全身过敏试验两种阳性物质选择的探讨

目的 比较两种阳性物质人血白蛋白、卵白蛋白对豚鼠主动全身过敏作用,为过敏性试验提供较好的阳性对照。方法 将豚鼠随机分为14组,以人血白蛋白、卵白蛋白(2、10、100 mg/只)、0.9%氯化钠注射液等受试物为对照,研究不同致敏剂量、激发剂量、激发时间等条件下,豚鼠全身主动过敏的反应情况。结果 在2~100 mg/只剂量范围内,人血白蛋白、卵白蛋白豚鼠主动全身过敏反应的发生率为100%。在2~10 mg/只剂量范围内,过敏症状发生程度随致敏剂量、激发剂量的增加而增加,相同剂量的卵白蛋白较人血白蛋白反应程度更强。结论 豚鼠主动全身过敏试验,阳性对照推荐使用卵白蛋白,剂量为2 mg/只。     

Vaccination of guinea pigs with DNA encoding Ag85A by gene gun bombardment

A DNA vaccine encoding Ag85A from Mycobacterium tuberculosis was administered to guinea pigs by epidermal gene gun bombardment and its protective efficacy was determined. Vaccination with Ag85A DNA twice significantly reduced the severity of pulmonary pathology and number of pulmonary colony-forming units (CFU) (p<0.01). When immunogenic synthetic Ag85A peptide was used as a booster, lung pathology was improved significantly and pulmonary CFU were reduced dramatically. Neither Ag85A DNA nor BCG Tokyo protected the guinea pigs from hematogenous spread of tubercle bacilli to the spleen because splenic granulomas without central necrosis were recognized. When the vaccinated guinea pigs were followed up for 7 months, the pulmonary lesions became fibrotic in guinea pigs vaccinated with Ag85A DNA plus Ag85A peptide, or BCG Tokyo, and no tubercle bacilli were detected. The protective efficacy of the tuberculosis Ag85A DNA vaccine was improved significantly by peptide boosting. It is concluded that dosage and peptide boosting are important in the induction of higher protective efficacy by a tuberculosis DNA vaccine.     

Complete absence of the αGal xenoantigen and isoglobotrihexosylceramide in α1,3galactosyltransferase knock-out pigs

Puga Yung GL, Li Y, Borsig L, Millard A‐L, Karpova MB, Zhou D, Seebach JD. Complete absence of the αGal xenoantigen and isoglobotrihexosylceramide in α1,3galactosyltransferase knock‐out pigs. Xenotransplantation 2012; 19: 196–206. © 2012 John Wiley & Sons A/S. Abstract: Background: Anti‐Galα1,3Galβ‐R natural antibodies are responsible for hyperacute rejection in pig‐to‐primate xenotransplantation. Although the generation of pigs lacking the α1,3galactosyltransferase (GalT) has overcome hyperacute rejection, antibody‐mediated rejection is still a problem. It is possible that other enzymes synthesize antigens similar to Galα1,3Gal epitopes that are recognized by xenoreactive antibodies. The glycosphingolipid isoglobotrihexosylceramide (iGb₃) represents such a candidate expressing an alternative Galα1,3Gal epitope. The present work determined whether the terminal Galα1,3Gal disaccharide is completely absent in Immerge pigs lacking the GalT using several different highly sensitive methods. Methods: The expression of Galα1,3Gal was evaluated using a panel of antibodies and lectins by flow cytometry and fluorescent microscopy; GalT activity was detected by an enzymatic assay; and ion trap mass spectroscopy of neutral cellular membranes extracted from aortic endothelial was used for the detection of sugar structures. Finally, the presence of iGb₃ synthase mRNA was tested by RT‐PCR in pig thymus, spleen, lymph node, kidney, lung, and liver tissue samples. Results: Aortic endothelial cells derived from GalT knockout pigs expressed neither Galα1,3Gal nor iGb₃ on their surface, and GalT enzymatic activity was also absent. Lectin staining showed an increase in the blood group H‐type sugar structures present in GalT knockout cells as compared to wild‐type pig aortic endothelial cells (PAEC). Mass spectroscopic analysis did not reveal Galα1,3Gal in membranes of GalT knockout PAEC; iGb₃ was also totally absent, whereas a fucosylated form of iGb₃ was detected at low levels in both pig aortic endothelial cell extracts. Isoglobotrihexosylceramide 3 synthase mRNA was expressed in all pig tissues tested whether derived from wild‐type or GalT knockout animals. Conclusions: These results confirm unequivocally the absence of terminal Galα1,3Gal disaccharides in GalT knockout endothelial cells. Future work will have to focus on other mechanisms responsible for xenograft rejection, in particular non‐Galα1,3Gal antibodies and cellular responses.     

Long-term effects of PERV-specific RNA interference in transgenic pigs

Semaan M, Kaulitz D, Petersen B, Niemann H, Denner J. Long‐term effects of PERV‐specific RNA interference in transgenic pigs. Xenotransplantation 2012; 19: 112–121. © 2012 John Wiley & Sons A/S. Abstract: Background: Porcine endogenous retroviruses (PERVs) represent a risk of xenotransplantation using porcine cells, tissues, or organs, as they are integrated in the porcine genome and have been shown to be able to infect human cells in vitro. To increase viral safety by RNA interference, transgenic pigs expressing a PERV‐specific small hairpin (sh)RNA targeted to a highly conserved sequence in the pol gene (pol2) were generated in which expression of PERVs was reduced (Xenotransplantation, 15, 2008, 38). However, it remains to be shown how long expression of the shRNA and the RNA interference is effective in reducing PERV expression. Methods: To analyze the long‐term duration of RNA interference, expression of the PERV‐specific pol2 shRNA and inhibition of PERV expression was studied repeatedly in fibroblasts and peripheral blood mononuclear cells (PBMCs) of transgenic pigs over a period of 3 yr, when animals were sacrificed and expression was studied in different organs. Expression of the PERV‐specific shRNA was measured using a newly developed real‐time PCR, and expression of PERV was measured using a PERV‐specific real‐time PCR. Results: Over a period of 3 yr, PERV‐specific shRNA and green fluorescent protein (GFP) as reporter of the vector system were consistently expressed in transgenic animals. PERV expression was significantly reduced during the entire period. Levels of PERV and shRNA expression were different in the various organs. PERV expression was highest in the spleen and the lungs and lowest in liver and heart. However, in all organs of the transgenic pigs, PERV expression was inhibited compared with the vector control animals. Conclusions: Transgenic pigs expressing PERV‐specific shRNA maintained their specific RNA interference long term, suggesting that PERV expression in the xenotransplants will be suppressed over extended periods of time.     

Anti‐gal antibodies in α1,3‐galactosyltransferase gene‐knockout pigs

Fang J, Walters A, Hara H, Long C, Yeh P, Ayares D, Cooper DKC, Bianchi J. Anti‐gal antibodies in α1,3‐galactosyltransferase gene‐knockout pigs. Xenotransplantation 2012; 19: 305–310. © 2012 John Wiley & Sons A/S. Abstract Serum anti‐galactose‐α1,3‐galactose (Gal) IgM and IgG antibody levels were measured by ELISA in α1,3‐galactosyltransferase gene‐knockout (GTKO) pigs (78 estimations in 47 pigs). A low level of anti‐Gal IgM was present soon after birth, and rose to a peak at 4–6 m, which was maintained thereafter even in the oldest pigs tested (at >2 yr). Anti‐Gal IgG was also present at birth, peaked at 3 m, and after 6 m steadily decreased until almost undetectable at 20 m. No differences in this pattern were seen between pigs of different gender. Total IgM followed a similar pattern as anti‐Gal IgM, but total IgG did not decrease after 6m. The data provide useful baseline data for future experimental studies in GTKO pigs, e.g., relating to the antibody response to WT pig allografts.     

Identification of human preformed antibody targets in GTKO pigs

Burlak C, Wang ZY, Chihara RK, Lutz AJ, Wang Y, Estrada JL, Tector AJ. Identification of human preformed antibody targets in GTKO pigs. Xenotransplantation 2012; 19: 92–101. © 2012 John Wiley & Sons A/S. Abstract: Background: Human preformed antibodies continue to recognize porcine xenografts, despite the advent of α‐galactosyltransferase knockout (GTKO) pigs. This study examined the potential reactivity of human preformed IgG and IgM antibodies toward antigens in the GTKO pig liver. Methods: Human serum was analyzed for the concentration of IgG, IgM, anti‐αgal antibody, anti‐non‐αgal antibody and cytotoxicity toward domestic and GTKO fibroblasts and liver sinusoidal endothelial cells (LSEC). We detected preformed antibodies in human serum directed toward GTKO pig liver cells and tissue samples using advanced proteomic techniques. The targets of preformed antibodies were identified by MALDI TOF TOF mass spectrometry and validated by confocal microscopy, immunoblot, and immunoprecipitation. Results: Human serum used in this study contained 2.06 μg/ml IgG and 0.013 μg/ml IgM directed toward GTKO fibroblasts. Human IgG and IgM bound to GTKO LSEC in a dose‐dependent manner and were cytotoxic. We detected 357 protein spots recognized by human IgG and 233 by human IgM. Two hundred and nineteen proteins were common to both human IgG and IgM. Mass spectrometry identified numerous immunoreactive proteins, of which 19 were membrane proteins on liver cells. The most significant to this study were α‐enolase, CFTR, and E‐cadherin, which were abundant in GTKO pig tissues and expressed on the surface of GTKO LSEC. Human IgG captured α‐enolase, CFTR, and E‐cadherin by immunoprecipitation validating the proteomic identification. Conclusion: These experiments indicate that several membrane antigens in GTKO pigs could be recognized directly by human IgG or IgM. Further studies on the contribution of these antigens to antibody‐mediated xenograft rejection are necessary.     

三氯乙烯染毒对豚鼠肝功能与凋亡基因表达的影响

目的探讨使用三氯乙烯(TCE)染毒对豚鼠肝功能和肝细胞凋亡基因(BAX、BAD、Bc1-2)表达的影响。方法将24只豚鼠随机分为3组,采用豚鼠最大值法(GPMT),设立TCE实验组、阴性对照组、阳性对照组,用皮内注射的方式分别注射TCE、橄榄油、2,4-二硝基氯苯(DNCB),实验结束后观察动物皮肤改变,应用自动生化分析仪检测动物肝功能指标,用荧光定量PCR检测肝细胞凋亡基因表达水平。结果 TCE实验组和阳性对照组动物出现明显皮肤损害。TCE实验组动物血清中丙氨酸转氨酶(ALT)、天冬氨酸转氨酶(AST)、乳酸脱氢酶(LDH)活力明显高于阴性对照组(P0.05或P0.01)。肝细胞BAX、BAD的mRNA表达水平比阴性对照组显著升高,Bc1-2表达水平下降(P0.05或P0.01)。结论三氯乙烯可诱导豚鼠产生明显的皮肤变态反应,引起实验动物肝功能指标改变和肝细胞凋亡基因表达水平明显改变。