Acceleration of scrapie disease in mice by an adenovirus

Coinfected mice were examined for a possible interaction between the scrapie agent and an adenovirus. A low titer (10(2) TCD50) of mouse adenovirus (MAdV) caused a significant acceleration of clinical signs of scrapie in mice infected 128 days previously with scrapie. In this experiment, the coinfected mice died 19 days earlier than mice infected with scrapie alone. When a higher titer of MAdV (10(4)-10(5) PFU) was used, a more drastic acceleration of scrapie disease was seen in mice infected 85 and 110 days previously with scrapie. At 85 days, coinfection caused mice to die 37 days earlier than mice infected with scrapie alone, whereas at 110 days, coinfection caused mice to die 52 days earlier than mice infected with scrapie alone. MAdV alone caused no clinical disease in normal mice. The brains of coinfected mice and mice that had been infected with scrapie alone showed a histopathology consistent with scrapie. A possible explanation for these findings is that the replication of the scrapie agent is accelerated by adenovirus. Defective parvoviruses are known to be helped by adenoviruses. Spleens from coinfected mice but not from mice infected with MAdV alone yielded, in cultures of BALB 3T3 cells, infectious MAdV and one or two smaller agents with the dimension and shape of a parvovirus.     

动力相关蛋白Drp1在羊瘙痒因子139A感染小鼠脑组织中变化的研究

目的 研究动力相关蛋白1(Drp1)在羊瘙痒因子139A感染的小鼠脑组织中的变化。方法 采用Western Blot方法检测Drp1在羊瘙痒因子139A感染的脑组织匀浆中的含量变化及其亚硝基化水平。采用组织免疫荧光方法检测Drp1在脑组织中的分布。结果 在羊瘙痒因子139A感染终末期小鼠脑组织匀浆中,Drp1总量略有降低。对感染不同时间点的动态分析结果显示Drp1含量呈逐渐降低趋势,终末期稍有回升。感染终末期脑组织中亚硝基化水平明显增高。组织免疫荧光显示正常和羊瘙痒因子139A感染终末期小鼠脑组织中,Drp1与神经元细胞存在共定位现象。结论 Drp1在小鼠中枢神经系统中主要分布于神经元细胞,在羊瘙痒因子139A感染的小鼠脑组织中,Drp1总量略有降低,另外亚硝基化水平明显增高,提示在羊瘙痒病感染的小鼠脑组织中,线粒体动力相关蛋白的表达量及翻译后修饰水平出现了变化,在感染过程中起着重要作用。     

CXCL1/CXCR2在羊瘙痒因子感染小鼠脑组织中的分布特征研究

目的 探究朊病毒感染小鼠脑组织CXC趋化因子配体1 (CXCL1)与CXC趋化因子受体2 (CXCR2)的分布特征。方法 通过免疫组织化学、免疫组织荧光双染实验明确羊瘙痒因子139A及ME7感染终末期小鼠脑组织中CXCL1/CXCR2的分布特征,确定CXCL1/CXCR2的靶细胞及与羊瘙痒因子样朊蛋白(PrPSc)沉积的关系。结果 通过全脑区免疫组化染色发现,CXCL1/CXCR2在羊瘙痒因子139A及ME7感染终末期小鼠脑组织中的含量明显升高,主要分布在海马、皮层、丘脑、小脑及延髓5个脑区。CXCL1与小胶质细胞和神经元细胞存在共定位,而CXCR2与神经元细胞存在共定位。在羊瘙痒因子139A及ME7感染终末期小鼠脑组织中CXCL1、CXCR2和PrP^Sc三者存在明显共定位。结论 CXCL1/CXCR2分布于朊病毒感染小鼠脑组织中朊病毒病理特征集中的脑区。     

Disappearance of scrapie virus from tissues of the mouse

Examination of newborn mice, inoculated intraperitoneally with high doses of scrapie virus, revealed that the virus could not be reisolated from their tissues after about 1 week following inoculation, until almost 1 year later. The inoculum was rapidly removed and was not detectable, although the animals became latently infected. Homogenization of whole inoculated newborn animals showed that only about 3% of virus could be recovered by the 2nd day postinoculation (p.i.). During the first 6 days p.i. the half-life of titratable scrapie was about 15 h. A further study of the rate of disappearance of clarified scrapie virus from blood after intravenous inoculation showed an even more rapid disappearance, with a half-life of 5.16 min. Prior treatment of the recipient mice with either carbon black or silica to block the reticuloendothelial system (RES) did not affect the rate of disappearance. It was concluded that the mouse possesses a very efficient means of scrapie virus removal from the blood which is not dependent upon an active RES. However, after 1 h the rate of disappearance changed dramatically; the residual virus level was very stable, with no significant drop during the next 21 h. This finding was compatible with the possibility that two forms of scrapie virus, with different removal rates, coexisted in the inoculum. Silica treatment caused a shortened scrapie incubation period.     

核转录因子-B(p65)在羊瘙痒因子139A感染小鼠脑组织中变化的研究

目的 研究NF-B（p65）在羊瘙痒因子139A感染小鼠脑组织中的变化。方法 通过蛋白质免疫印迹法及免疫组织化学的方法检测p65在139A感染的脑组织均浆中的含量变化。利用免疫荧光方法检测p65在神经元及胶质细胞中的分布情况。结果 在139A感染终末期小鼠脑组织均浆中，p65含量下降，差异有统计学意义。对感染不同时间点的动态分析结果显示，p65含量呈先升高随后逐渐降低趋势。免疫组织化学显示，139A感染终末期小鼠大脑皮层p65含量明显下降。免疫组织荧光显示在正常和139A感染终末期小鼠脑组织中，p65与神经元细胞存在共定位现象。结论 NF-B（p65）在小鼠中枢神经系统中主要分布于神经元细胞，在139A感染的小鼠终末期脑组织中，p65总量明显下降，提示在139A感染的小鼠脑组织中，NF-B（p65）出现了变化，在疾病进程中发挥一定作用。     

Prophylactic effect of dietary seaweed Fucoidan against enteral prion infection

Dietary seaweed fucoidan delays the onset of disease of enterally infected mice with scrapie when given orally for 6 days after infection, but not when given before the infection. This effect was not modified at a tested fucoidan dose range and appeared to reach the maximum level at a concentration of 2.5% or less in feed. Daily uptake of fucoidan might be prophylactic against prion diseases caused by ingestion of prion-contaminated materials, although further evaluation of its pharmacology remains to be done.     

Description of a BHK/21 cell line persistently infected with Junin virus: its use in diagnostic procedures

A BHK/21 cell line persistently infected by an arenavirus is described. During four consecutive passages, 30-45% of the cells showed granular cytoplasmic antigen by indirect immunofluorescence, employing both Argentine hemorrhagic fever convalescent sera and sera from animals immunized with Junin virus. Virus isolated from the cells killed suckling mice but not adult mice and protected guinea pigs against further challenge with the virulent prototype strain of Junin virus. Neutralization tests showed that the virus isolated from the cells was neutralized by anti-Junin virus antisera. The usefulness of this cell line in rapid immunofluorescent serological procedures is described.     

Naturally occurring lymphocyte-mediated immunity to endogenous type-C virus in the mouse. Blocking of the lymphocyte reactivity with antisera to the virus

The natural immune response in mice to their endogenous type-C viruses involves a complex interaction between cellular and humoral immune mechanisms. The virus-specific immune reactivities are a function of age and appear only subsequent to endogenous virus expression. Cellular immune activity was found to reside in a population of lymphocytes that were characterized as natural killer cells based on their absence of theta surface antigens or immunoglobulin or complement receptors. Cellular and humoral virus-specific immune responses co-occur in the same animal and pretreatment of virus-positive target cells with sera from virus-positive aging mice is capable of partially blocking the cytotoxic activity of reactive lymphocytes. The blocking activity of sera from individual mice increases as a function of age and endogenous virus expression and is highly correlated with the virus-specific complement-dependent cytotoxic activity of these sera. Mouse sera, whether naturally immune or immune as a result of hyperimmunization with type-C virus, exhibit blocking activity that can be removed by absorption with purified type-C virus or purified viral glycoprotein (gp 70) but not by absorption with noninfected syngeneic cells. High-titered and highly specific antisera directed against certain individual R-MuLV structural proteins reveal blocking activity. Monospecific antisera to gp 70 and p 12 exhibited high-titered blocking reactivities which are absorbable by the respective purified proteins. Blocking activity of antisera directed against other viral structural proteins could not be excluded with certainty. These findings raise the possibility that immunity in the mouse to endogenous type-C virus or virus-infected cells involves competition between serum-blocking activity and natural-killer cell activity and further provides a unique model system for studying the mechanism of action of blocking antisera known to have monospecific reactivity against defined and purifiable transplantation antigens.     

羊瘙痒因子139A感染引起小鼠脑组织中的1-ACT表达增加

目的 探究1-ACT在羊瘙痒因子139A感染小鼠脑组织中的变化情况。方法 利用蛋白免疫印迹、免疫组织化学、间接免疫荧光及荧光共聚焦方法分析羊瘙痒因子139A感染小鼠脑组织中1-ACT表达的变化和分布特点。结果 蛋白免疫印迹方法显示在羊瘙痒因子139A感染小鼠终末期脑组织中1-ACT的含量较正常对照小鼠明显上调且随着潜伏期的延长而逐渐增加;免疫组织化学方法发现1-ACT主要分布于羊瘙痒因子139A感染小鼠的皮层、丘脑和小脑区域;间接免疫荧光实验显示羊瘙痒因子139A感染终末期小鼠脑组织中补体成分C3含量明显增加,同时荧光共聚焦实验表明1-ACT与补体成分C3存在明显的共定位现象。结论 羊瘙痒因子139A感染终末期小鼠脑组织中1-ACT含量明显增加。     

Scrapie-associated tubulofilamentous particles in scrapie hamsters.

Examination of thin sections from the cerebral cortex of scrapie-infected hamster brains revealed characteristic circular 26-30 nm diameter tubulofilamentous particles, identical to those previously described in both experimentally induced scrapie in mice, hamsters and natural scrapie of sheep, bovine spongiform encephalopathy and human Creutzfeldt-Jakob disease and mice and chimpanzees infected with Creutzfeldt-Jakob disease. Longitudinal forms of tubulofilamentous particles were also observed in dendrites and myelinated axons. Both transverse and longitudinally cut particles were readily distinguished from microtubules and synaptic vesicles, thus there appears to be no relationship between tubulofilamentous particles, and microtubules or synaptic vesicles.     

Western blot analysis of antibody specificities in subacute sclerosing panencephalitis: reactivity to measles virus proteins produced in persistently infected cells

The specificity of serum antibodies from patients with subacute sclerosing panencephalitis (SSPE) and seropositive controls to measles virus proteins produced in acutely and persistently infected human cells was examined by western blot analysis. Sera from both SSPE patients and controls reacted to the H, N, and F1 virus proteins produced in acutely infected AV3 cells. However, while SSPE-derived sera reacted with the same proteins in persistently infected cells (AV3Al/MV), most control sera failed to react with the hemagglutinin protein produced in such cells (Hp). Most sera also reacted poorly with the M protein from either source, and the reactivity to the P protein was variable. Although the exact reason(s) for the different reactivities to the proteins were not determined, differences in antibody concentration did not appear to be responsible. The dramatic differences in the reactivity of SSPE and control sera to the Hp protein suggest that either the protein coevolves in persistent infections or multiple forms of the protein evolve in such infections and SSPE patients develop broad-spectrum humoral immunity as a consequence of exposure to them. Alternatively, over time there may be selective loss of some H-reactive antibody subsets by individuals who contract measles, but do not develop SSPE.     

Tubulovesicular structures in experimental Creutzfeldt-Jakob disease and scrapie

Tubulovesicular structures, measuring 20-50 nm in diameter, were found in dilated neuronal processes in brains from mice infected with the Fujisaki strain of Creutzfeldt-Jakob disease virus. These particles were similar to those observed in brains from hamsters infected with scrapie. These structures are consistently present in naturally occurring and experimentally induced spongiform encephalopathies, irrespective of the host species or virus strain. Their role in pathogenesis is undetermined.     

肾综合征出血热病毒特异性抗体的自身血凝实验的建立及其临床应用

目的建立检测肾综合征出血热（HFRS）病毒抗体的自身血凝实验（AGEN）方法。方法选择对人红细胞有高亲和力的2C8单抗，采用木瓜酶消化和亲和层析方法制备其Fab片段，并采用亲和层析方法提纯HFRSV G1和G2糖蛋白，一步法偶联制成双价试剂，玻片上室温5分钟，检测HFRS患者全血及血清中特异性抗体，并对患者病程进行动态分析，实验中用IFAT做平行对照。结果HFRS住院患者全血54例，AGEN检测阳性者49例（90．78％），IFAT检测阳性者为45例（83．33％）。统计学处理AGEN与IFAT检出率没有显著性差异（P〉0．05）。非HFRS患者全血90例，AGEN89例为阴性，1例为可疑阳性。20例HFRS患者血清分别用AGEN和IFAT测定HFRS病毒抗体。两种方法分别检出18例（90％）和17例（85％），统计学上两种方法没有显著性差异。对54例HFRS患者病程分析，发热期15例检出12例，多尿期39例检出37例，与IFAT的测定结果基本一致。结论AGEN实验可直接采患者耳血测定HFRS病毒特异性抗体，该方法仅用20μl耳血，5分钟内出结果，具有微量、快速、简便的优点，而且AGEN方法不仅可检出全血中的抗体，也可检测血清中的抗体。所以AGEN即可作为实验诊断，又可作为流行病学调查的方法，病程分析表明AGEN可作为HFRS早期实验诊断方法。     

Autoantibodies in the sera of Trypanosoma cruzi-infected individuals with or without clinical Chagas disease

Variations in the levels and the specificities of autoantibodies directed against a panel of antigens (cytoskeleton proteins, DNA, laminin) were analyzed in the sera from two groups of humans infected with Trypanosoma cruzi. One group was constituted of apparently healthy blood donors (BD) and the other of patients with clinically confirmed Chagas disease (CCH). In both infected groups, a high proportion but not all sera exhibited dramatic enhancement of IgM and IgG autoantibodies directed against all antigens tested. Sera positive for IgG autoantibodies were generally found more frequently in the CCH than in the BD group, except for anti-actin antibodies more often present in BD sera. Anti-laminin IgG antibodies were present in a similar number of individuals in both groups. Although the titers of anti-laminin IgG antibodies were in general higher in CCH, their dissociation constants were in the same range (7 × 10^?8–10^?7M) in both groups. IgG autoantibodies were demonstrated to be polyreactive with laminin and other self antigens as well. Circulating immune complexes were present in sera from both groups and the activity of the antibodies dissociated from these complexes was directed against all the antigens of the panel. Although the IgE concentration was significantly enhanced in several subjects from both groups, the incidence of positive sera was higher in the CCH (60%) than in the BD (39%) group. Our results demonstrate that autoantibodies with the characteristics of natural autoantibodies are found in both T. cruzi-infected apparently healthy individuals and patients. © 1993 Wiley-Liss, Inc.     

结核分枝杆菌Rv1009结构域多肽的免疫学特性研究

目的 研究结核分枝杆菌Rv1009结构域多肽的免疫学特性.方法 用原核表达的Rv1009结构域多肽免疫BALB/c小鼠3次.每次间隔2周.用ELISA法检测免疫小鼠血清中特异性抗体滴度.分离免疫小鼠的脾淋巴细胞,体外用抗原再刺激后,用MTT比色法检测免疫小鼠脾淋巴细胞的增殖指数.ELISA方法检测淋巴细胞悬液中γ干扰素(IFN-γ)、白细胞介素(IL)-10和IL-12的产生水平.另一部分免疫的小鼠经尾静脉感染MTB毒株H37Rv,4周后,计数脾脏细菌负荷数.结果 Rv1009结构域多肽免疫小鼠血清特异性抗体滴度为1:12 800.淋巴细胞增殖指数为2.40±0.18,明显高于生理盐水对照组的0.90±0.21.ELISA方法检测Rv1009结构域多肽免疫组IFN-γ、IL-10和IL-12水平为(1432±30)ng/L、(503±11)ng/L和(311±11)ng/L,显著高于生理盐水对照组的(256±20)ng/L、(76±6)ng/L和(56±8)ng/L(P<0.01).与生理盐水免疫组(细菌负荷6.64±0.13)相比较,Rv1009结构域多肽免疫组小鼠,对攻击感染后抗MTB在脾脏中增殖有显著作用(细菌负荷为4.86±0.14,P<0.05),但不及BCG免疫组的3.81±0.16.结论 Rv1009结构域多肽有可能作为新型结核疫苗的候选组分.     

In vivo efficacy of anidulafungin and caspofungin against Candida glabrata and association with in vitro potency in the presence of sera

In vitro studies have demonstrated that anidulafungin has greater potency than caspofungin against Candida glabrata. However, data from in vivo studies demonstrating that it has superior efficacy are lacking. The objective of this study was to compare the activities of anidulafungin and caspofungin against C. glabrata in a murine model of disseminated candidiasis. Two clinical C. glabrata isolates were used, including one with reduced caspofungin susceptibility. MICs were determined by broth microdilution in the presence and absence of sera. For the animal studies, mice were immunosuppressed with 5-fluorouracil one day prior to intravenous inoculation. Treatment with anidulafungin and caspofungin (0, 0.5, 1, 5, and 10 mg/kg of body weight per day) was begun 24 h later and was continued through day 7 postinoculation. The CFU were enumerated from kidney tissue. According to the standard microdilution methodology, anidulafungin had superior in vitro activity. However, this enhanced potency was attenuated by the addition of mouse and human sera. Caspofungin reduced the kidney fungal burden at lower doses compared to that achieved with anidulafungin in mice infected with the isolate with the lower MIC. Against the strain with the elevated caspofungin MIC, both anidulafungin and caspofungin were effective in reducing the kidney fungal burden at the higher doses studied. Despite the greater in vitro activity of anidulafungin in the absence of sera, both echinocandins were similarly effective in reducing the fungal burden in kidney tissue. The superior in vitro activity of anidulafungin did not confer enhanced in vivo efficacy against C. glabrata.     

Preclinical changes in weight of scrapie-infected mice as a function of scrapie agent-mouse strain combination

Several inbred strains of mice were injected with different scrapie agents and their total body weight was monitored throughout the incubation period. As a control, mice were injected with normal mouse brain homogenate. For most combinations of scrapie agent and mouse strain, weights during the preclinical phase were similar to or lower than the average weight of controls. For some combinations there was a significant increase in weight (compared to controls) during the latter part of the preclinical phase of disease. The effect was dependent on both agent and mouse strain, i.e., in some cases a mouse strain showed the increase with one scrapie agent but not another and some scrapie agents caused the increase in one inbred strain of mouse but not in another strain. The increase in weight was due to accumulations of fat rather than a generalized increase in weight of various organs. With one mouse strain (SJL), there was increased vacuolation seen in the hypothalamus of mice injected with scrapie agents that showed the increase in weight compared to the lesion intensity with an agent which did not cause the weight increase.     

Improved control of SARS-CoV-2 by treatment with a nucleocapsid-specific monoclonal antibody

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein is the main antigen in all approved COVID-19 vaccines and is also the only target for monoclonal antibody (mAb) therapies. Immune responses to other viral antigens are generated after SARS-CoV-2 infection, but their contribution to the antiviral response remains unclear. Here, we interrogated whether nucleocapsid-specific antibodies can improve protection against SARS-CoV-2. We first immunized mice with a nucleocapsid-based vaccine and then transferred sera from these mice into naive mice, followed by challenge with SARS-CoV-2. We show that mice that received nucleocapsid-specific sera or a nucleocapsid-specific mAb exhibited enhanced control of SARS-CoV-2. Nucleocapsid-specific antibodies elicited NK-mediated, antibody-dependent cellular cytotoxicity (ADCC) against infected cells. To our knowledge, these findings provide the first demonstration in the coronavirus literature that antibody responses specific to the nucleocapsid protein can improve viral clearance, providing a rationale for the clinical evaluation of nucleocapsid-based mAb therapies to treat COVID-19.     

THE SEROLOGICAL DIAGNOSIS OF RELAPSING FEVER

1. Spirochetes of relapsing fever have been separated from the blood of heavily infected mice and rats by hemolysing with saponin, followed by repeated washing of the spirochetal suspension with physiological saline. 2. Spirochetes obtained in this manner appear to have broad antigenic specificity. Antigens of this type fixed complement in the presence of serum obtained from man or animals infected with one or other of the recognized strains or "species" of relapsing fever spirochetes. Macroscopic agglutination of the antigens likewise was observed with sera from the same sources. 3. Positive serological reactions were not observed with convalescent sera obtained following infection with other diseases, for example, typhus fever, malaria, Rocky Mountain spotted fever, Weil''s disease, syphilis, and typhoid fever. Hyperimmune sera prepared against other pathogens also failed to react with the relapsing fever antigens. 4. No apparent change in the antigen occurred following storage in the ice box for as long as 4 months. 5. The results indicate that treatment of the spirochetes of relapsing fever with saponin yields a relatively stable antigenic preparation which may prove useful in the serological diagnosis of this disease.     

Idiotypes expressed early in experimental Schistosoma mansoni infections predict clinical outcomes of chronic disease

In murine Schistosoma mansoni infections, schistosome-specific cross-reactive idiotypes (CRI) are present in the sera of mice with moderate splenomegaly syndrome (MSS) at 20 wk after infection. In contrast, sera from animals that have the more severe hypersplenomegaly syndrome (HSS) at 20 wk of infection do not express these CRI in their sera. To examine when these regulatory CRI first appear in mice that eventually develop MSS, sera from infected animals were monitored for CRI from 1.5 to 20 wk of infection. In mice that eventually developed MSS, CRI were detected by 5 to 6 wk after infection, plateaued by 8 to 10 wk, and persisted through 20 wk of infection. Animals that developed HSS pathology or that died before 20 wk of infection never expressed CRI. Moreover, CRI levels present in the sera of mice at 6 wk of infection were inversely correlated with splenomegaly and hepatic fibrosis, but not with parasitologic measures, at 20 wk after infection. These results suggest that critical events occur very early in some schistosome infections that induce the production of regulatory idiotypes and that the presence or absence of these idiotypes predicts, and possibly determines, subsequent morbidity.