Shioda Lab/Division of Infectious Disease  Department of Viral Infections

Although we have been studying HIV for more than 20 years, now we are mainly studying mosquito-borne viral diseases such as dengue and chikungunya virus infections. We are conducting epidemiological studies in Thailand and molecular studies in Osaka, Japan.

 

Molecular characterization of dengue and chikungunya viruses

Dengue and chikungunya viruses are transmitted by Aedesmosquitos and cause febrile diseases. Dengue virus sometimes causes shock syndrome after decline of fever and chikungunya virus causes arthralgia. We are conducting molecular epidemiology of these viruses in Thailand and Bangladesh by using molecular clock analysis. There are apparent variations in growth kinetics among isolated viruses and we are trying to elucidate factors affecting these differences.

 

Characterization of anti-dengue antibodies

Anti-dengue antibodies show both neutralizing and enhancing effect on virus infection. We are analyzing several monoclonal antibodies hoping to find neutralizing antibody without any enhancing effect. There are four serotypes of dengue virus. Some antibodies neutralize all four serotypes while other potently neutralize only one serotype. Antibodies with strong neutralizing activity without any enhancement can be used as antibody drug. We will also analyze anti-viral antibodies in asymptomatic infection.

 

Antiviral host factors and their application to a cure for HIV infection

HIV does not establish a productive infection in any monkey other than the chimpanzee. Also, the sensitivity of HIV infection and rate of disease progression vary from individual to individual. To date, several anti-HIV host restriction factors, including TRIM5α and TRIMCyp, have been identified as responsible for these phenomena. Currently, we are trying to elucidate the molecular mechanism(s) underlying the anti-HIV activity of these factors. We also aim to cure HIV infection by establishing novel reproductive medicine-based strategies, including iPS cells from HIV patients.

 

 

  • Fig. 1. Phylogeographical analysis of dengue virus type 2.

  • Fig. 2.A neutralizing antibody (green) and envelope dimer of
    dengue virus type 2 (pale blue and orange). Amino acid resides critical for antibody binding are highlighted with red and blue.

Staff

  • Prof.: Tatsuo Shioda
  • Assoc. Prof.: Emi E. Nakayama
  • Asst. Prof.: Tadahiro Sasaki

Website

Publications

  • (1) Emergence of genotype Cosmopolitan of dengue virus type 2 and genotype III of dengue virus type 3 in Thailand. Phadungsombat J et al. PLoS One. (2018) 13(11):e0207220. doi:10.1371/journal.pone.0207220
    (2) HIV-1 is more dependent on the K182 capsid residue than HIV-2 for interactions with CPSF6. Saito A. et al., Virology (2019) 532:118-126.
    (3) Genotype replacement of dengue virus type 3 and lineage replacement of dengue virus type 2 genotype Cosmopolitan in Dhaka. Bangladesh 2017. Suzuki K., et al. Infect Genet Evol. (2019) 75: 103977
    (4) Multiple pathways to avoid IFN-β sensitivity of HIV-1 by mutations in capsid. Sultana T., et al., J Virol. (2019) 93(23)
    (5) Two distinct lineages of chikungunya virus cocirculated in Aruba during the 2014- 2015 epidemic. Phadungsombat J., et al. Infect Genet Evol. (2020) 78:104129
    (6) The 4th and 112th residues of viral capsid cooperatively modulate capsid-CPSF6 interactions of HIV-1. Saito A., et al. AIDS Res Hum Retroviruses (2020) doi:10.1089/AID.2019.0250.