肝 炎 病 毒肝 炎 病 毒 A 型 : 急性肝炎 Picornavirus B 型 : 慢行肝炎 ( 肝癌 ) Hepadnavirus C 型 : 慢性肝炎 ( 肝癌 ) Flavivirus D 型 : 慢性肝炎 Deltaviridae E 型 : 急性肝炎 Calicivirus
Hepatitis Delta Virus RNA Nucleocapsid (HDAg) HBsAg Major protein Middle protein Large protein Phospholipid
Challenges of Hepatitis Delta Virus Viroid-like circular RNA with a protein Make both full-length RNA replication and subgenomic mRNA transcription Carry out RNA-dependent RNA transcription, but do not encode RNA-dependent polymerase: Cellular RdRP?
Hepatitis C virus 170 million carriers in the world (2% of population) Tendency to cause persistent infection, leading to chronic hepatitis, liver cirrhosis, hepatoma A flavivirus with single-stranded RNA
Hepatitis C virus Relative risks of hepatocellular carcinoma in non-Asians of Los Angeles County HBV (-), HCV (-)1.0 HBV (+)5.1 HCV (+)22.3 HCV (+), HBV (+)56.2 (Adapted from Yuan et al. )
HCV Genes and Gene products Lindenbach et al, Nature 933, 2005 ER
Life cycle of HCV Nature 436, 933-938 (18 August 2005 ) ER or Golgi ? rER ? Endosome Receptor Golgi ?
HCV Genome and HCV Replicon R. Bartenschlager et al. / Antiviral Research 60 (2003) 91–102
HCV HCV: A non-retroviral oncogenic RNA virus Frequent Mutations of p53 (Teramoto et al., Cancer Res.) B cell Lymphoma Hepatocellular Carcinoma Hypermutation of Ig Ivanovski et al., Blood) Chronic Infection Liver Cirrhosis Lymphoproliferative Diseases (mixed Cryoglobulinemia)
Establishment of a B-cell lymphoma cell line (SB cells) Established from the spleen of an HCV-positive patient with B-cell lymphoma and mixed cryoglobulinemia: proof that HCV infects B cells in vivo. Produces infectious virus particles that are capable of infecting B cells but not hepatocytes. The immunoglobulin gene is monoclonal but undergoes continuous evolution
Molecular mechanism of viral lympho- vs hepatotropism Harvest Detection (qRT-PCR) In vitro Transcribed RNA Electroporation into Huh7.5 and Raji
SB virus RNA, but not JFH-1 Virus, Replicates in Raji Cells Raji
JFH-1 Virus, but not SB Virus RNA, Replicates in Huh7.5 Cells Huh7.5 SB virus is lymphotropic. JFH-1 virus is hepatotropic.
HCV induces a mutator phenotype HCV infection causes a 5-10-fold increase in mutation frequency of cellular genes, including immunoglobulin (Ig) and somatic genes, e.g., p53 or -catenin genes. Increased mutations are seen in in vitro HCV-infected B cells and in PBMC from HCV-infected individuals. Mutations are amplified in the HCV-infected lymphoma and hepatoma.
MK 0 2 4 8 16 2 4 8 16 Day p.i. Raji JT DSBs VHVH HCV RNA Mock HCV (+) HCV (-) DW MK - HCV+ - HCV+ D C B A E F DSBs in V H DSBs in p53 DSBs 872 603 234 872 603 234 Double-stranded DNA breaks in HCV- infected cells (by linker-ligation PCR)
Challenges of Hepatitis C Virus Vaccines Therapy (interferon and ribavirin) Mechanism of HCV pathogenesis (persistent infection) and oncogenesis The mechanism of immune escape The role of B and T cell infection
Challenges of Infectious Diseases Antibiotics Small pox Polio Hepatitis B virus Human papillomavirus HIV Malaria Drug-resistant tuberculosis
Emerging and reemerging infectious diseases Courtesy of Dr. Anthony Fauci, NIAID SARS Avian flu HIV Marburg Measles