Uirusu
Online ISSN : 1884-3433
Print ISSN : 0042-6857
ISSN-L : 0042-6857
Volume 57, Issue 2
Displaying 1-10 of 10 articles from this issue
Reviews
  • Hiroyuki YAMAMOTO, Tetsuro MATANO
    2007 Volume 57 Issue 2 Pages 133-139
    Published: 2007
    Released on J-STAGE: June 05, 2008
    JOURNAL FREE ACCESS
    A logical approach for prophylactic HIV-1 vaccine development begins by recognition that the regimen needs to contain viruses which are not cleared by primary host immune responses and develop persistent infection. Hence the required strategy is different from the one against self-remitting acute infections which aims at eliciting robust host immune responses in advance by infection mimicry.
    Host adaptive immune responses do play a central role in primary resolution from acute HIV-1 and simian immunodeficiency virus (SIV) infection, but as observed in the non-remitting disease course, their function is not fully exerted, leading to failure in viral containment. Either overcoming the limitations of antiviral immunity in natural infection or augmenting the effectors potentially capable of controlling virus replication would be essential for development of an effective HIV-1 vaccine. This approach is hand-in-hand with understanding of the reversibility of various steps leading to establishment of persistent HIV-1 infection.
    This article reviews the interplay between HIV-1/SIV and the infected host, mainly focusing on macaque models of SIV infection and characterization of the two major wings of adaptive immunity, cytotoxic T lymphocytes (CTLs) and neutralizing antibodies. Discussed in parallel are the up-to-date topics of HIV-1 vaccine development including our recent progress.
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  • Kohji MORIISHI, Yoshiharu MATSUURA
    2007 Volume 57 Issue 2 Pages 141-149
    Published: 2007
    Released on J-STAGE: June 05, 2008
    JOURNAL FREE ACCESS
    Hepatitis C virus (HCV) infects approximately 170 million people worldwide including 2 million in Japan and induces serious chronic hepatitis that results in the development of steatosis, cirrhosis and ultimately hepatocellular carcinoma. The current combination therapy using pegylated interferon alpha and a nucleotide analogue ribavirin achieved a sustained virological response in about half population of individuals infected with HCV genotypes 1a and 1b. More than two-thirds of the HCV-positive population has been chronically infected with genotype 1 in Western countries and Japan. Therefore, more effective therapeutics and preventative measures are needed for the treatment of hepatitis C patients who are not responsive to the current chemotherapy. HCV core protein is well known to be the viral capsid protein as well as the pathogenic factor that induces steatosis and hepatocellular carcinoma in the transgenic mice. In this review, we summarize the current status of our knowledge regarding the molecular mechanism by which HCV core protein induces liver steatosis and hepatocellular carcinoma and discuss on a future perspective for the development of novel therapeutics for chronic hepatitis C.
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  • Yasuko MORI
    2007 Volume 57 Issue 2 Pages 151-158
    Published: 2007
    Released on J-STAGE: June 05, 2008
    JOURNAL FREE ACCESS
    Herpesvirus entry into host cells occurs by recognition of specific cellular receptor(s) with viral envelope glycoproteins. Nucleocapsids formed in nucleus are released into cytoplasm, and acquire tegument proteins there. Nucleocapsids with tegument proteins bud into intracellular vesicles formed in infected cells, which are thought to be derived from Golgi apparatus, trans-Golgi network or endosomes. However, the precise mechanisms involved in virus final envelopment are poorly understood. Here, I review our current knowledge regarding herpesvirus entry into host cells and virus assembly.
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  • Naoyoshi MAEDA, Yasunobu YOSHIKAI
    2007 Volume 57 Issue 2 Pages 159-170
    Published: 2007
    Released on J-STAGE: June 05, 2008
    JOURNAL FREE ACCESS
    RNA tumor viruses as classified in Retroviruses have been isolated and identified to induce tumors in a variety of animals including chickens, mice, and rats, or even in human in the last 100 years, since the first one has been reported in 1908. The RNA tumor viruses have been historically classified into two groups, acute transforming RNA tumor viruses and nonacute RNA tumor viruses. Acute transforming RNA tumor viruses are basically replication-defective and rapidly induce tumors by expressing the viral oncogenes captured from cellular genome in host cells. The first oncogene derived from Rous sarcoma virus was the src non-receptor tyrosine kinase, which has been identified to play the significant roles for signal transduction. On the other hand, nonacute RNA tumor viruses, which consist of only gag, pro, pol, and env regions but do not carry oncogenes, are replication-competent and could activate the cellular proto-oncogenes by inserting the viral long terminal repeat close to the proto-oncogenes to induce tumors with a long incubation period, as is termed a promoter insertion. These molecular mechanisms have been thought to induce tumors. However, very recently several reports have described that the retroviral structural protein Envelope could directly induce tumors in vivo and transform cells in vitro. These are very unusual examples of native retroviral structural proteins with transformation potential. In this review we look back over the history of oncogenic retrovirus research and summarize recent progress for our understanding of the molecular mechanisms of oncogenic transformation by retrovirus Envelope proteins.
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Special Issue:Viral Infections of Current Concern
  • Nobuhiko OKABE
    2007 Volume 57 Issue 2 Pages 171-179
    Published: 2007
    Released on J-STAGE: June 05, 2008
    JOURNAL FREE ACCESS
    In 2007, measles outbreak occurred mainly among teen/twenties in Japan, and many high-school, universities and colleges were closed to reduce spread of measles. Some high school students became measles when they were in foreign countries where measles has been eliminated, visited as school excursion.
    Since introducing measles vaccine as routine immunization, number of measles has been reduced remarkably in Japan. However, we had measles outbreak in 2001, and total annual patients number were estimated 200-300 thausands mainly among young infants. The main reason was low immunization coverage of measles at 1 year old, and operation to give measles vaccine as "the gift for 1 year old birthday" has been introduced widely. Then immunization coverage at this age was increased up from 50-60% (2001) to 80-90% (2006) and total measles number was estimated less than 10,000 at 2005 and 2006, however, measles outbreak occurred this time among teen/twenties in 2007. The total number of adult measles (more than 15 y.o.) were higher than the number of them at 2001 outbreak.
    To discontinue outbreak and to eliminate measles, enhancement of measles control activities has been introduced in Japan. Two doses policy with measles and rubella (MR) vaccine at 1 y.o. and before elementary school has been introduced since 2006 and further, supplementary immunization with MR at 1st grade in junior high school and 3rd grade in high school for 5 years from 2008 will start to eliminate measles by 2012. Reporting system will be also changed from sentinels system to notify to all measles cases system.
    In this paper, present epidemiological situation on measles in Japan, measles elimination strategy in WPRO, and plan for measles elimination in Japan are described.
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  • Haruko SHIRATO-HORIKOSHI, Naokazu TAKEDA
    2007 Volume 57 Issue 2 Pages 181-189
    Published: 2007
    Released on J-STAGE: June 05, 2008
    JOURNAL FREE ACCESS
    Norovirus (NoV), a member of the family Caliciviridae, is a major cause of water and food-borne acute nonbacterial gastroenteritis, and forms many morphologically similar but antigenically diverse groups of viruses. The virus-like particles (VLPs) derived from the prototype strain of NoV, Norwalk virus (NV/68), bind to histo-blood group antigens (HBGAs). HBGAs are carbohydrates that contain structurally related saccharide moieties, and are found in saliva and mucosal secretions from intestinal epithelial cells of secretor individuals who have FUT2 gene encoding a fucosyltransferase. From volunteer challenge studies, there is strong evidence that the carbohydrate-binding is essential for the NV/68 infection. Non-secretors, who do not express FUT2 fucosyltransferase and consequently do not express H type 1 or Leb in the gut, were not infected after the challenge with NV/68. However, other NoV VLPs display different ABH and Lewis carbohydrate-binding profiles, and indeed epidemiological studies showed that some NoV strains could infect individuals with another ABH phenotypes. GII/4 is known to be global epidemic strain and bound more HBGAs when compared with other strains. The strength of the transmission of GII/4 strains may be linked with their wide recognition of HBGAs. It is obvious that HBGAs are important factors to determine the host specificity, although it is still unclear whether the HBGAs act as the primary receptor or enhance NoV infectivity. Further investigation is needed.
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  • Naoto ITO, Makoto SUGIYAMA
    2007 Volume 57 Issue 2 Pages 191-198
    Published: 2007
    Released on J-STAGE: June 05, 2008
    JOURNAL FREE ACCESS
    Rabies virus causes lethal neurological symptoms in humans and animals. Rabies epidemics have continued to occur throughout the world, despite the fact that rabies can be effectively prevented by vaccination. The development of inexpensive and safe attenuated live vaccines and the establishment of cures are the keys to control rabies. To achieve these objectives, it is important to elucidate mechanism by which rabies virus causes disease. Here, previous studies on the pathogenesis of rabies virus are reviewed and ways to apply previous findings to rabies control are also discussed.
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  • Tomohiko TAKASAKI
    2007 Volume 57 Issue 2 Pages 199-206
    Published: 2007
    Released on J-STAGE: June 05, 2008
    JOURNAL FREE ACCESS
    West Nile virus (WNV), a member of the family Flaviviridae (genus Flavivirus), is a mosquito-borne virus first isolated in 1937 in the West Nile district of Uganda. The disease in humans is characterized by a dengue-like illness with fever, and a more severe form is characterized by central nervous system involvement, including encephalitis, meningitis, and myelitis. WN encephalitis was first reported in the Western Hemisphere in the summer of 1999, there was an outbreak in New York City. Epidemic WNV strains in North America are severely pathogenic, however, attenuated WNV strains were found in Texas and Mexico in 2003. The principal vectors of WNV transmission in North America are Culex. pipiens, Cx. quinquefasciatus, Cx. restuans, Cx salinarius and Cx talsalis. The number of WN fever case has exceeded 27,000 since 1999 in the United States and 4,600 since 2002 in Canada. The first imported case of West Nile fever in Japan was confirmed in September, 2005. The patient had returned to Japan from the United States and developed symptoms the next day. There is currently no WN vaccine for use in humans. An inactivated WNV vaccine for use in horses has been available since 2001. A DNA vaccine, a chimeric live attenuated vaccine, and a recombinant vaccine have also been licensed for use in horses.
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Topics
  • Yoshiko OKAMOTO, Yoshiyuki NAGAI
    2007 Volume 57 Issue 2 Pages 207-215
    Published: 2007
    Released on J-STAGE: June 05, 2008
    JOURNAL FREE ACCESS
    The program of Founding Research Centers for Emerging and Reemerging Infectious Diseases was commenced in 2005 with an outline for Japanese universities and research institutions to establish bilateral collaboration research bases in countries where emerging and reemerging infections are breaking out or will likely break out. So far, six universities and two institutions are participating in the program and ten collaboration bases have been established in six countries (five in Asia and one in Africa). Each research base aims to contribute to the security and safety of the partner and own countries by facilitating better understanding of infectious diseases, technology innovation in diagnosis, therapy and prevention, and human resources development. The experiences of the Reseau International des Instituts Pasteur (RIIP), France, and the Wellcome Trust Southeast Asian Tropical Medicine Research Units (Oxford Network), United Kingdom, which appear to share similar missions, suggest that infectious diseases research that is based on overseas research bases can produce first-time results through the building of long-term mutual trust with the counterparts. By referring to these networks as models, Japan's program should be implemented over the long run but not be based on a short-time perspective. Thus, secure funding is a major issue.
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  • Tetsuya MIZUTANI
    2007 Volume 57 Issue 2 Pages 217-226
    Published: 2007
    Released on J-STAGE: June 05, 2008
    JOURNAL FREE ACCESS
    We developed a new system for detection of viral nucleic acids because rapid detection of pathogens is necessary to prevent potential outbreaks of infectious diseases. This system, named rapid determination of viral RNA sequences (RDV), involves whole-genome amplification and a new direct sequencing technique. Using the RDV system, it is possible to obtain viral nucleic acid sequences within 2 days. The nucleic acid sequences of SARS-CoV and West Nile virus, which represent emerging and re-emerging infectious viruses, were determined from infectious viral culture supernatant by the RDV method. We demonstrated the clinical application of this system in human specimens and its diagnostic usage in mosquitoes. Furthermore, new adenovirus and herpesvirus were found in bats using the RDV method.
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