Elution time of velogenic, mesogenic and lentogenic strains of Newcastle disease virus was determined. The differences in their elution time were also calculated. Four samples, each of a velogenic strain (VGF2), a mesogenic strain (Komarov) and a lentogenic strain (LaSota) were used for hemagglutination test with 0.6% chicken red blood cells. The time it took for wells of the end hemagglutination points (highest dilution that gave agglutination) to elute was recorded as elution time for each sample. The mean elution time of the three strains of Newcastle disease virus differed significantly (p < 0.05). The velogenic strain gave the highest mean elution time of 118 min, followed by the mesogenic strain with 59 min and the lentogenic strain with 25 min. Based on this result it appears that elution time could form a basis for rough characterization of isolates of Newcastle disease virus into the three major strains.
Animals ; Chickens/blood ; Erythrocytes/*virology ; Hemagglutination Tests ; *Hemagglutination, Viral ; Newcastle disease virus/isolation&purification/*pathogenicity

A virus strain, showing cytopathic effect in Vero cell, was isolated from plasma of a fattening pig in Gyeonggi province, Korea in October 1999. The evaluation of physicochemical/biological properties of the isolate showed that the virus, KV1899, inoculated suckling mouse showed paralysis and died within 7 days post-inoculation, the mouse brain suspension had hemagglutinating activity with goose RBC. Pathogenicity of isolate was carried out by intracranial and intraperitoneal inoculation of 3-4 weeks mice. The mice inoculated with isolate showed 10 4.5 LD50/ 0.03 ml and 10 3.0 LD50/0.5 ml according to the inoculation route. The isolate was identified as RNA and enveloped virus using IUDR and chloroform sensitivity test. The virus particles within the infected Vero cell were measured to be 40-50 nm in size by electron microscopy. The isolate was further characterized by immuno-fluorescence assay using Japanese encephalitis virus (JEV) specific monoclonal antibodies. Reverse transcription polymerase chain reaction (RT-PCR) revealed the presence of JE specific conserved sequences in this isolate. The artificially inoculated pigs had HI titer of 320 to 2,560 against JEV at 14 to 42 days post inoculation. We confirmed this isolate as Japanese encephalitis virus. It was the second isolation of JEV in pigs in Korea.
Animals ; Antibodies, Viral/analysis ; Cercopithecus aethiops ; Cytopathogenic Effect, Viral ; Encephalitis Virus, Japanese/*classification/*isolation & purification/ultrastructure ; Encephalitis, Japanese/pathology/*veterinary/virology ; Fluorescent Antibody Technique, Indirect/veterinary ; Hemagglutination Inhibition Tests/veterinary ; Hemagglutination Tests/veterinary ; Korea ; Mice ; Microscopy, Electron/veterinary ; RNA, Viral/analysis ; Reverse Transcriptase Polymerase Chain Reaction/veterinary ; Swine ; Swine Diseases/pathology/*virology ; Vero Cells/virology

BACKGROUNDTo understand the optimal condition of single radial hemolysis (SRH) for diagnosis of avian influenza A (H5N1) virus in order that SRH could be performed in general laboratories.

METHODSThe effect of different concentration of virus and species of red blood cells, as well as kind and concentration of agarose on testing sensitivity of SRH was determined. Meanwhile the sensitivity and specificity of this method were compared with those of micro-neutralization test.

RESULTSThe optimal condition of SRH included the viral concentration of 1000 HA units per 0.1 ml packed chicken red blood cells, the agarose concentration of 1.0%, the compliment added into agarose-virus-rbc slides after diffusion of sera. The sensitivity and specificity of SRH were very similar to those of micro-neutralization test. Meanwhile, no cross reaction between antibodies, especially antibodies against N1 antigens, H5N1 and H1N1 viruses was detected.

CONCLUSIONThe sensitivity and specificity of SRH were very similar to those of micro-neutralization assay. SRH could be performed in normal laboratories and be used for testing large scale serum samples.

Animals ; Antibodies, Viral ; analysis ; Chick Embryo ; Guinea Pigs ; Hemagglutination Inhibition Tests ; Humans ; Influenza A Virus, H5N1 Subtype ; immunology ; Influenza, Human ; diagnosis ; immunology ; Neutralization Tests ; Orthomyxoviridae Infections ; diagnosis ; immunology

OBJECTIVETo understand the epidemic status of avian influenza A virus in chickens and men in Guangzhou area and to prevent men suffering from avian influenza A (H5N1) virus.

METHODSEtiologic and serological surveys were conducted in chickens and men who were working in the poultry farms and slaughter house. Viruses were isolated with both MDCK cells and embryonated chicken eggs. Hemagglutination inhibition tests were performed by routine method.

RESULTSAnti-H9N2 antibody was found in 12.8% of the chickens and 5.1% of the workers.

CONCLUSIONSAvian influenza virus H9N2 subtype existed in chickens and this subtype of influenza A virus might infect men.

Animals ; Antibodies, Viral ; blood ; Chickens ; virology ; China ; Hemagglutination Inhibition Tests ; Humans ; Influenza A Virus, H9N2 Subtype ; immunology ; isolation & purification ; Influenza in Birds ; virology ; Influenza, Human ; virology

In our previous study, a panel of 52 broadly cross-reactive H5-specific monoclonal antibodies (MAbs) were generated and characterized. The 13D4, one of these MAbs, has been demonstrated to protect mice against lethal challenge by 4 strains of H5N1 avian influenza virus representing the currently prevailing genetic populations, clades 1, 2.1, 2.2, and 2.3. Here, we further cloned the gene of the 13D4 MAb and constructed a single-chain variable fragment. Then, the 13D4 single-chain antibody (scFv) was expressed in secretory maner in Pichia pastoris. The supernatant of the culture was concentrated and subjected to ammonium sulfate precipitation. The purity of the 13D4 scFv was around 90% in SDS-PAGE following ion-exchange chromatography. We further investigated its binding property using hemagglutination inhibition (HI) test and blocking ELISA. The results indicated that the 13D4 scFv shared the same binding sites and comparable HI titer with the prototype murine 13D4 Mab. In conclusion, an anti-H5 single-chain wide-spectrum neutralizing antibody is prepared successfully in yeast system.
Antibodies, Viral ; genetics ; Hemagglutination Inhibition Tests ; Immunoglobulin Fragments ; genetics ; immunology ; Influenza A Virus, H5N1 Subtype ; immunology ; Pichia ; genetics ; Single-Chain Antibodies ; genetics ; immunology

A hybridoma cell line 1G4A7 secreting monoclonal antibody (McAb) specific to hemagglutinin of avian paramyxovirus type 2 (APMV-2) was developed by fusing the spleen cells of APMV-2 immunized BAlb/c mice with SP2/0 myeloma cells. The immunoglobulin subclass of 1G4A7 was IgG1 with light chain kappa and the affinity constant against APMV-2 was 1.02 X 10(10). Identified by HI and indirect ELISA, the McAb titers in ascities were 10 log 2 and 1 : 10(6) respectively. The McAb did not cross react with the common avian viruses, showing good specificity. There existed obvious differences in antigenitic relationship among APMV-2 viruses analyzed by HI and indirect ELISA using McAb 1G4A7.
Animals ; Antibodies, Monoclonal ; biosynthesis ; immunology ; Avulavirus ; immunology ; Enzyme-Linked Immunosorbent Assay ; Hemagglutination Inhibition Tests ; Hemagglutinins, Viral ; immunology ; Mice ; Mice, Inbred BALB C

OBJECTIVETo understand the distribution of influenza A H9N2 virus in chickens and men in Shenzhen area.

METHODSVirus isolation was performed in embryonated hen s eggs with routine method. The antibody to H9N2 virus was detected with micro-hemagglutination inhibition (HI) test, then the results were checked by using the neutralization assay in MDCK cells.

RESULTSTotally 27 strains of influenza A H9N2 virus were isolated from chickens in farm markets in Shenzhen, whereas no H9N2 virus was isolated from men. Approximately 26% of human sera with the HI titers > or =20 to H9N2 virus were detected. However only 7% of chicken sera with the HI titers > or =20 to H9N2 virus were detected. Meanwhile the HI titer and (MGT) of antibody to H9N2 virus in human sera increased with age. It was also found that there was a close relationship between HI antibody titer to H9N2 virus in human sera and occupation.

CONCLUSIONSThe distribution of influenza A H9N2 virus in chicken and men in Shenzhen was rather wide. The human H9N2 virus infection probably derived from chicken H9N2 virus.

Animals ; Antibodies, Viral ; blood ; Chickens ; China ; epidemiology ; Hemagglutination Inhibition Tests ; Humans ; Influenza A Virus, H9N2 Subtype ; Influenza A virus ; classification ; immunology ; isolation & purification ; Influenza, Human ; epidemiology ; virology ; Seroepidemiologic Studies

OBJECTIVETo study the safety and immunogenicity of the measles-mumps-rubella combined vaccine (MMR) produced by Beijing Biological Product Institute.

METHODSChildren aged 10-12 years, 2-2.5 years and 8-12 months were selected to be vaccinated with Beijing MMR vaccine (test vaccine). Other groups of children with similar nature were vaccinated with measles vaccine, mumps vaccine and rubella vaccine while using imported MMR vaccine (control vaccine) as controls.

RESULTSThe safety of the Beijing MMR vaccine was confirmed after vaccinating 32 children above 2 years old. Among 104 children of 8-12 months were vaccinated with Beijing MMR vaccine, only 6.7% of the children had transient fever and 1.9% had signs of rashes but with no other signs observed. The positive seroconversion rates of measles, rubella and mumps anti-HI were 100%, 100% and 85.7% respectively. GMT also showed high lever.

CONCLUSIONThe MMR vaccine (Beijing) had good safety and immunogenicity which might be used to be the bases enhance immunization of measles.

Antibodies, Viral ; blood ; Child ; Child, Preschool ; Freeze Drying ; Hemagglutination Inhibition Tests ; Humans ; Measles-Mumps-Rubella Vaccine ; adverse effects ; immunology ; Vaccines, Attenuated ; adverse effects ; immunology

Antibodies, Viral ; blood ; Child ; China ; Female ; Hemagglutination Inhibition Tests ; Humans ; Influenza Vaccines ; adverse effects ; immunology ; Influenza, Human ; prevention & control ; Male ; Orthomyxoviridae ; immunology ; Safety ; Vaccination

OBJECTIVETo study influenza epidemic and analyze antigenic and genetic characterization of the predominant strains in Wuhan area in 2003.

METHODSEpidemiological data and specimens from influenza patients were collected from surveillance sites weekly. Viruses were isolated from the specimens. Three H3 isolates were chosen to do antigenic analysis by hemagglutination inhibition (HI) test and their HA1 region was sequenced.

RESULTSTotally 58 influenza viruses were isolated from 418 specimens, 57 of them were identified as H3 subtype and 1 of them was B subtype; both monthly positive rate and numbers of influenza like illness had two peaks of winter and summer, the highest peak appeared in July. The 3 new H3 isolates were antigenically different from vaccine strain A/Panama/2007/99, 14 amino acid changes have been found in HA1 domain of these 3 strains compared with A/Panama/2007/99, phylogenetic analysis also confirmed the difference in HA1 domain.

CONCLUSIONSInfluenza epidemic had two peaks in Wuhan area in 2003. The activity of H3 virus was strengthened remarkably. And they are antigenically and genetically different from the vaccine strain.

Amino Acid Sequence ; Antigens, Viral ; immunology ; China ; epidemiology ; Genes, Viral ; Glycosylation ; Hemagglutination Inhibition Tests ; Humans ; Influenza A Virus, H3N2 Subtype ; genetics ; immunology ; isolation & purification ; Influenza, Human ; epidemiology ; virology ; Molecular Sequence Data ; Phylogeny ; Sequence Analysis, Protein