In vitro effect of isoprinosine on rabies virus

The in vitro effect of isoprinosine, an antiviral compound, was evaluated on ERA and VA319 rabies viral strains. Isoprinosine diminished the number of immunofluorescent cells, viral titers, and structures involved in rabies virus replication. Mechanism of antiviral action was probably mediated by modification of the polyribosome conformation and function.     

Stimulatory effect of avian influenza virus on chicken lymphocytes

A study was conducted to examine the effect of avian influenza virus (AIV) on chicken lymphocyte activation. Unprimed or Brucella abortus antigen (Ag)-primed lymphocytes were incubated with various doses of the T-cell mitogen concanavalin A (Con A) or Ag, respectively, plus serial dilutions of inactivated AIV for 72 hr, and cell proliferation was measured via uptake of tritiated thymidine. AIV enhanced the proliferative response to Con A or Ag by 150% or better, and the enhancement decreased in a viral dose-dependent manner. The effects were more readily observed in cells that had not been maximally activated by the Con A or Ag. The enhanced response was observed in lymphocytes from both white rock and white leghorn breeds of chicken and in mature peripheral blood lymphocytes or immature thymocytes. The viral activity could be abrogated by pre-treatment of the viral preparation with AIV-specific antisera or prior adsorption of the AIV with chicken erythrocytes. These results indicate that AIV can interact with and modify the in vitro activity of chicken lymphocytes and may exert modulatory effects on the avian immune system.     

伐昔洛韦对猪伪狂犬病病毒复制的抑制作用

本研究确定伐昔洛韦的体外和体内抗猪伪狂犬病病毒作用,确定伐昔洛韦对Vero细胞的最大无毒质量浓度为4g/L,抑制PRV野毒在Vero细胞中复制的最低有效质量浓度为3g/L。用1个LD50的PRV对小鼠进行攻毒,在攻毒后48h给服不同剂量的伐昔洛韦,确定了伐昔洛韦能够为小鼠提供完全保护的最低剂量为3 mg/只。PRV攻毒后,未给服伐昔洛韦组小鼠表现典型的神经症状并全部死亡,而给药组小鼠临床健康并全部存活。与给药组小鼠相比,未给药组小鼠脑、肺组织中的PRV病毒载量明显高于给药组小鼠,且随时间延长一直增加。脑、肺组织呈现PRV感染的特征性病理变化。伐昔洛韦给药组小鼠相应组织中的病毒载量和脾脏T淋巴细胞分泌PRV特异性Th1型细胞因子水平在攻毒后72h逐渐降低。试验结果显示,伐昔洛韦无论在体内、体外均能够有效抑制PRV的复制。     

Characterization of influenza A virus with nine segments: effect gene segment on virus property

The influenza A virus genome consists of eight segments of negative-strand RNA. In previous study, we generated a recombinant influenza virus with nine segments by reverse genetics. In present study, we evaluated characteristics of the recombinant influenza virus. The recombinant virus exhibited similar property to wild-type virus on virion morphology, virion composition, plaque phenotype and other aspects. Whereas, the recombinant virus propagated to lower titers than did wild-type virus in cells and mice, and there was decreased protein level and vRNA incorporation in the recombinant virions compared to wild-type H9N2 virions. Our results indicated that influenza A virus with eight segments exhibits more advantages than the virus with nine segments.     

金丝桃素对口蹄疫病毒的体外抗病毒实验

本文报道了金丝桃素体外抗口蹄疫病毒（FMDV）的研究结果。采用双抗体捕获抗原法、病毒滴度测定、MTT法、组织细胞培养等方法均检测到抗病毒作用。结果显示：金丝桃素在BHK-21细胞感染FMDV前、后及同时加入，都有明显抑制细胞病变的作用。金丝桃素使FMDV的TCID50从8．5下降到6．25。双抗体捕获抗原法检测到金丝桃素有效抑制FMDVBHK-21细胞的吸附、融合，抑制率可达59．72％。研究结果提示：金丝桃素在体外有抗口蹄疫病毒作用，抑制口蹄疫病毒与宿主细胞的吸附、融合是抗病毒的重要途径之一。     

The effect of pseudorabies (Aujeszky''s) virus infection on young mature boars and boar fertility.

This study was designed to determine the effects of experimental inoculation with pseudorabies virus on the reproductive tracts of young adult boars. Pseudorabies virus was inoculated intranasally into 12 boars and intrapreputially into four boars. All animals seroconverted after nasal or preputial inoculation. Semen abnormalities were observed 21 days postinoculation with partial recovery by 50 days postinoculation. Virus was isolated from the preputial sheath of two intrapreputially inoculated boars 12 days postinoculation. It was concluded that pseudorabies virus infection can be established via preputial inoculation and that decreased spermatogenesis and infertility can result.     

蜂胶对NDV的灭活作用效果观察

本文通过鸡胚接种的方法就蜂胶乙醇浸出物对NDV的灭活作用进行了试验观察，结果表明常温下3min，1mg／ml的47．5％乙醇稀释液对ND克隆-30具有灭活作用。含蜂胶乙醇浸出物0．1mg／ml的95％乙醇稀释液、含蜂胶乙醇浸出物10mg／ml的47．5％乙醇稀释液、含蜂胶乙醇浸出物10mg／ml的生理盐水稀释液；37℃3min，含蜂胶乙醇浸出物0．1mg／ml的95％乙醇稀释液、含蜂胶乙醇浸出物0．1mg／ml的47．5％乙醇稀释液、含蜂胶乙醇浸出物10mg／ml的生理盐水稀释液均对ND克隆-30具有完全灭活作用。     

五种中草药抗鸡新城疫病毒作用研究

本实验对山茶叶、轮叶党参、卵叶芍药、苦味西葫芦、狼毒大戟5种中草药的提取物进行了体外、体内抗鸡新城疫病毒(NDV)筛选，结果表明山茶叶抗NDV作用较强，其对NDV的灭活率和抑制率分别为56．14％、58．59％。     

Immunosuppressive effect of infectious bursal disease virus strains of variable virulence for chickens.

Infection of chicks with attenuated Lp and Sp clones of the RF-1 strain of infectious bursal disease virus was shown to exert no immunosuppressive effect, whereas the parent strain RF-1tc and the original virulent strain RF-1wt were immunosuppressive. One-day-old chicks infected with Lp and Sp clones showed no suppression of immunological response to live Newcastle disease vaccines B1 and TCND, and to bivalent infectious coryza vaccine. On the other hand, infection with RF-1tc or RF-1wt strains was immunosuppressive for these vaccines. The immunosuppressive effect of RF-1tc and RF-1wt strains was more pronounced for infectious coryza vaccine and B1 vaccine than for TCND vaccine. The immunosuppressive effect of RF-1tc and RF-1wt strains was lower when chicks were infected with these strains at the age of 21 days than when they were infected at one day of age.     

Immunosuppressive effect of a highly virulent infectious bursal disease virus isolated in Japan.

The immunosuppressive effect of infectious bursal disease virus (IBDV) on vaccination against Newcastle disease (ND) was compared among 2-, 3-, and 4-week-old chickens inoculated with the highly virulent IBDV field isolate 90-11 and the reference serotype 1 strain GBF-1. In all age groups, isolate 90-11 severely suppressed antibody response to ND vaccination and protective vaccinal immunity against ND. In contrast, chickens inoculated with strain GBF-1 and vaccinated with ND vaccine were well protected from the ND virus challenge. The mitogenic response to phytohemagglutinin of splenic lymphocytes from chickens inoculated with isolate 90-11 or strain GBF-1 was significantly lower than that of uninoculated controls. There was no difference between the two inoculated groups in responsiveness, although lymphocyte depletion in the thymus was more severe in chickens inoculated with isolate 90-11 than in chickens inoculated with strain GBF-1.     

Pilot study of the effect of acemannan in cats infected with feline immunodeficiency virus.

Acemannan, a complex carbohydrate shown to stimulate interleukin-1, tumor necrosis factor alpha and prostaglandin E2 production by macrophages, has also demonstrated antiviral activity in vitro against human immunodeficiency virus, Newcastle disease virus and influenza virus. A pilot study was undertaken to determine acemannan's effect in 49 feline immunodeficiency virus (FIV) infected cats with clinical signs of disease (Stage 3, 4 or 5), 23 of which had severe lymphopenia. Cats received acemannan either by intravenous (Group 1) or subcutaneous (Group 2) injection once weekly for 12 weeks, or by daily oral (Group 3) administration for 12 weeks. Upon entry into the study, cats were randomly assigned to one of the three groups. Laboratory analyses were performed at the beginning of the study and at Weeks 6 and 12. Cats were allowed to continue with a predetermined maintenance regimen of acemannan after completing the 12-week study. Thirteen cats died during the course of treatment. Upon necropsy, the most frequent histopathologic findings were neoplastic, kidney and pancreatic disease. Friedman's two-way ANOVA test showed no significant differences in efficacy among groups administered acemannan by the different routes. Therefore, groups were combined and a signed-ranks test was used to determine changes over time. A significant increase was seen in lymphocyte counts (P < 0.001). Neutrophil counts decreased significantly (P = 0.007), as did incidence of sepsis (P = 0.008). When cats entering with lymphopenia were analyzed separately, a much greater increase in lymphocyte counts was noted (235%) compared with non-lymphopenic cats (42%). A survival rate of 75% was found for all three groups. Thirty-six of 49 animals are alive 5-19 months post-entry. These results suggest that acemannan therapy may be of significant benefit in FIV-infected cats exhibiting clinical signs of disease.     

Inhibitory effect of African swine fever virus on lectin-dependent swine lymphocyte proliferation

The incubation of swine peripheral blood mononuclear cells (PBMC) with African swine fever (ASF) virus preparations strongly inhibited the proliferative response of lymphocytes to PHA and other lectins. The inhibition, which persisted after inactivation of the virus by UV radiation, was dependent upon the dose and the time that virus preparations were present in cultures. When virus preparations were fractionated by ultracentrifugation, the inhibitory activity resulted to be soluble, whereas no activity was found in the sedimented viral fraction. However, the preincubation during 4 days of this sedimented fraction with swine PBMC, before the addition of the mitogen, restored the inhibitory activity. The results obtained suggest that the inhibition is mediated by one or more soluble factors released by swine PBMC after coincubation with ASF virus in a time dependent process. These factors show a molecular weight between 40 and 80 kDa by gel filtration chromatography. The inhibitory activity described in the present paper is an indication of inhibition of lymphocyte function produced by ASF virus which can help to understand how this virus escapes from the host immune system.     

The effect of caprine arthritis encephalitis virus infection on production in goats

Three consecutive years of monitoring 248 goats in the same flock, found that the first lactation milk yield was significantly higher in seronegative (578 L) than in seropositive (447 L) animals but this difference disappeared in the subsequent second to fourth lactations. No significant differences were found in the proportions of seronegative and seropositive does in the flock, the percentage of animals culled, the number of offspring, or in the number of cases of udder bacterial infection, irrespective of age.Removal of kids from their dams before suckling and the feeding of pasteurised colostrum resulted in reduced numbers of seropositive animals. Nevertheless, by approximately 24 months of age, 76.9% of these initially seronegative animals were seropositive, a factor that significantly contributed to flock seropositivity. This finding could be attributed to lateral virus transmission from seropositive to seronegative kids because of lack of segregation within the flock.