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1.  Immunization of rabbits with synthetic peptides derived from a highly conserved β-sheet epitope region underneath the receptor binding site of influenza A virus 
Background
There is increasing concern about the speed with which health care providers can administer prophylaxis and treatment in an influenza pandemic. Generally, it takes several months to manufacture an influenza vaccine by propagation of the virus in chicken eggs or cultured cells. Newer, faster protocols for the production of vaccines that induce broad-spectrum immunity are therefore highly desirable. We previously developed human monoclonal antibody B-1 that shows broadly neutralizing activity against influenza A virus H3N2. B-1 recognizes an epitope region that includes an antiparallel β-sheet structure underneath the receptor binding site of influenza hemagglutinin (HA). In this study, the efficacy of a synthetic peptide vaccine derived from this epitope region against influenza A was evaluated.
Materials and methods
Two peptides were synthesized, the upper and lower peptides. These peptides comprise amino acid residues 167–187 and 225–241, respectively, of the B-1 epitope region of HA, which is involved in forming the β-sheet structure. Both peptides were then coupled to keyhole limpet hemocyanin, and the peptides, alone or in combination, were used to immunize rabbits. The resulting antibody responses were examined by enzyme-linked immunosorbent assay. The upper peptide, but not the lower peptide, elicited antibodies that were reactive to HA. Interestingly, the use of both peptides together could elicit antibodies with a higher reactivity to HA than either peptide alone. The antibodies were found to react to HA at the N-terminus of the upper peptide, which is exposed at the surface of trimeric HA on influenza virions.
Discussion
The higher production of HA-reactive antibodies following immunization with both peptides suggests that the upper peptide forms the effective epitope structure in the binding state, and the lower peptide enhances the production of HA antibodies. This study could be the first step towards the development of pandemic viral vaccines that can be produced within short time periods.
doi:10.2147/BTT.S50870
PMCID: PMC3821756  PMID: 24235814
influenza A; hemagglutinin; epitope; synthetic peptide; rabbit
2.  Significant neutralizing activities against H2N2 influenza A viruses in human intravenous immunoglobulin lots manufactured from 1993 to 2010 
Influenza A H2N2 virus, also known as the Asian flu, spread worldwide from 1957 to 1967, although there have been no cases reported in humans in the past 40 years. A vaccination program was introduced in Japan in the 1960s. Older Japanese donors could have been naturally infected with the H2N2 virus or vaccinated in the early 1960s. Human intravenous immunoglobulin (IVIG) reflects the epidemiological status of the donating population in a given time period. Here, the possible viral neutralizing (VN) activities of IVIG against the H2N2 virus were examined. Hemagglutination inhibition (HI) and VN activities of IVIG lots manufactured from 1993 to 2010 in Japan and the United States were evaluated against H2N2 viruses. High HI and VN activities against H2N2 viruses were found in all the IVIG lots investigated. HI titers were 32–64 against the isolate in 1957 and 64–128 against the isolates in 1965. VN titers were 80–320 against the isolate in 1957 and 1280–5120 against the isolates in 1965. Both the HI and VN titers were higher against the isolate in 1965 than in 1957. Thus, antibody titers of IVIG against influenza viruses are well correlated with the history of infection and the vaccine program in Japan. Therefore, evaluation of antibody titers provides valuable information about IVIGs, which could be used for immune stimulation when a new influenza virus emerges in the human population.
doi:10.2147/BTT.S33495
PMCID: PMC3413397  PMID: 22888217
IVIG; influenza; H2N2; neutralization
3.  Hepatitis E virus in Norway rats (Rattus norvegicus) captured around a pig farm 
BMC Research Notes  2012;5:4.
Background
Hepatitis E virus (HEV) transmitted via the oral route through the consumption of contaminated water or uncooked or undercooked contaminated meat has been implicated in major outbreaks. Rats may play a critical role in HEV outbreaks, considering their negative effects on environmental hygiene and food sanitation. Although the serological evidence of HEV infection in wild rodents has been reported worldwide, the infectivity and propagation of HEV in wild rats remain unknown. To investigate if rats are a possible carrier of HEV, we studied wild Norway rats (Rattus norvegicus) that were caught near a pig farm, where HEV was prevalent among the pigs.
Methods
We examined 56 Norway rats for HEV. RNA from internal organs was examined for RT-PCR and positive samples were sequenced. Positive tissue samples were incubated with A549 cell line to isolate HEV. Anti-HEV antibodies were detected by ELISA.
Results
Sixteen rats were seropositive, and the HEV RNA was detected in 10 of the 56 rats. Sequencing of the partial ORF1 gene from 7 samples resulted in partially sequenced HEV, belonging to genotype 3, which was genetically identical to the HEV prevalent in the swine from the source farm. The infectious HEVs were isolated from the Norway rats by using the human A549 cell line.
Conclusions
There was a relatively high prevalence (17.9%) of the HEV genome in wild Norway rats. The virus was mainly detected in the liver and spleen. The results indicate that these animals might be possible carrier of swine HEV in endemic regions. The HEV contamination risk due to rats needs to be examined in human habitats.
doi:10.1186/1756-0500-5-4
PMCID: PMC3284388  PMID: 22217009
4.  Development of Two Types of Rapid Diagnostic Test Kits To Detect the Hemagglutinin or Nucleoprotein of the Swine-Origin Pandemic Influenza A Virus H1N1▿  
Since its emergence in April 2009, pandemic influenza A virus H1N1 (H1N1 pdm), a new type of influenza A virus with a triple-reassortant genome, has spread throughout the world. Initial attempts to diagnose the infection in patients using immunochromatography (IC) relied on test kits developed for seasonal influenza A and B viruses, many of which proved significantly less sensitive to H1N1 pdm. Here, we prepared monoclonal antibodies that react with H1N1 pdm but not seasonal influenza A (H1N1 and H3N2) or B viruses. Using two of these antibodies, one recognizing viral hemagglutinin (HA) and the other recognizing nucleoprotein (NP), we developed kits for the specific detection of H1N1 pdm and tested them using clinical specimens of nasal wash fluid or nasopharyngeal fluid from patients with influenza-like illnesses. The specificities of both IC test kits were very high (93% for the HA kit, 100% for the NP kit). The test sensitivities for detection of H1N1 pdm were 85.5% with the anti-NP antibody, 49.4% with the anti-HA antibody, and 79.5% with a commercially available influenza A virus detection assay. Use of the anti-NP antibody could allow the rapid and accurate diagnosis of H1N1 pdm infections.
doi:10.1128/CVI.00269-10
PMCID: PMC3067372  PMID: 21228147

Results 1-5 (5)