1 / 106

Dr. Jing Qian Dept. of Medical Microbiology and Parasitology Medical school, Zhejiang university

Lectures for biomedical students. Hepatitis Virus, Hemorrhagic fever viruses, Arbovirus 肝炎病毒、出血热病毒和虫媒病毒. Dr. Jing Qian Dept. of Medical Microbiology and Parasitology Medical school, Zhejiang university Email: jingqian@zju.edu.cn 2014.5.29. Hepatitis & Hepatitis Virus. 肝炎和肝炎病毒.

gannon-hardin
Télécharger la présentation

Dr. Jing Qian Dept. of Medical Microbiology and Parasitology Medical school, Zhejiang university

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Lectures for biomedical students Hepatitis Virus, Hemorrhagic fever viruses, Arbovirus 肝炎病毒、出血热病毒和虫媒病毒 Dr. Jing Qian Dept. of Medical Microbiology and Parasitology Medical school, Zhejiang university Email: jingqian@zju.edu.cn 2014.5.29

  2. Hepatitis & Hepatitis Virus 肝炎和肝炎病毒

  3. Definitions and Introduction • Hepatitis- Inflammation of the liver, destruction of hepatocytes • Acute Infection-Icteric (黄疸的) phase • Chronic Infection-May progress to: • Hepatic fibrosis, cirrhosis, liver failure • Increased risk of hepatocellular carcinoma

  4. Icteric phase/Jaundice • * Skin, sclera (巩膜), underneath tongue

  5. Viral Hepatitis - Historical Perspectives Enterically transmitted “Infectious” A E Viral hepatitis NANB Parenterally transmitted B D C “Serum” F, G, TTV ? other

  6. HAV • HBV • HCV • HDV • HEV • Focus on the viruses • Viral structure, biology • Transmission and epidemiology • Pathogenesis and immunity • Clinical findings • Laboratory diagnosis • Treatment and Prevention

  7. Hepatitis A Virus (HAV) • “Epidemic jaundice” • “Infectious hepatitis” (1912) • Hepatitis A

  8. Biological properties Immature particle mature particle http：//www.ncbi.nlm.nih.gov/books • Picornavirus classified as Enterovirus 72 in 1980s, later classified Heparnavirus • 27 nm naked (non-enveloped) icosahedral capsid • Extremely stable capsid

  9. Biological properties • Picornavirus classified as Enterovirus 72 in 1980s, later classified Heparnavirus • 27 nm naked (non-enveloped) icosahedral capsid • Positive-sense, single-stranded RNA genome, 7500 nt NCR: 非编码区 IRES:内部核糖体进入位点 3B-VPg/primer protein 病毒基因组连接蛋白

  10. Biological properties • Picornavirus classified as Enterovirus 72 in 1980s, later classified Heparnavirus • 27 nm naked (non-enveloped) icosahedral capsid • Positive-sense, single-stranded RNA genome • Resistance: Stronger than enterovirus, resistant to detergents, acid (pH 1.0 for 2h), 60℃ for 1h，survive for months in fresh water and salt water • one serotype

  11. Biological properties • Picornavirus classified as Enterovirus 72 in 1980s, later classified Heparnavirus • 27 nm naked (non-enveloped) icosahedral capsid • Positive-sense, single-stranded RNA genome • Extremely stable capsid • Resistance: Stronger than enterovirus, resistant to detergents, acid (pH 1.0 for 2h), 60℃ for 1h，survive for months in fresh water and salt water • 1 serotype and 7 genotypes • 1个血清型 主要抗原决定簇VP1 • 7个基因型（VP1）

  12. Biological properties • Picornavirus classified as Enterovirus 72 in 1980s, later classified Heparnavirus • 27 nm naked (non-enveloped) icosahedral capsid • Positive-sense, single-stranded RNA genome • Extremely stable capsid • Resistance: Stronger than enterovirus, resistant to detergents, acid (pH 1.0 for 2h), 60℃ for 1h，survive for months in fresh water and salt water • 1 serotype and 7 genotypes • Animal model and cell culture

  13. Biological properties • Picornavirus classified as Enterovirus 72 in 1980s, later classified Heparnavirus • 27 nm naked (non-enveloped) icosahedral capsid • Positive-sense, single-stranded RNA genome • Extremely stable capsid • Resistance: Stronger than enterovirus, resistant to detergents, acid (pH 1.0 for 2h), 60℃ for 1h，survive for months in fresh water and salt water • 1 serotype and 7 genotypes • Animal model and cell culture

  14. Transmission of HAV • Fecal-Oral spread • contaminated water or food ( shellfish, green onions) • Risk factors: poor sanitation and hygiene, overcrowding, daycare

  15. Epidemiology

  16. Pathogenesis Not fully understood • Enters bloodstream through gastrointestinal epithelium • Replicates in hepatocytes and Kupffer cells • Released by exocytosis, not cell lysis in cultured cells • It is likely that attack by cytotoxic T cells causes the demage to the hepatocytes • Goes into bile, intestine, excreted in feces • Shedding of virus for 10 days prior to any symptoms

  17. Immunity 无论显性感染或隐性感染 　　均能产生抗-HAV的 IgM和IgG抗体 抗-HAV的IgM在急性期和恢复早期出现 阳性可作为甲肝的确诊依据 抗-HAV的IgG在恢复后期出现 有保护作用，维持终身

  18. Clinical findings Acute Hepatitis A Infection • May be mild to asymptomatic in children • Abrupt onset of disease in adults • “Self-limited”-controlled by immune system • Low overall mortality from fulminant (暴发性的) hepaptitis • Higher risk with simultaneous liver disease such as cirrhosis due to alcohol or chronic Hepatitis B or C

  19. Diagnosis of HAV Clinical syndrome Detection of anti-HAV specific antibodies IgM titer in acute infection, positive for 4-6 months IgG titer present for decades Research testing -Virus feces by electron microscopy (no cell culture available) RNA PCR

  20. Treatment and Prevention of HAV No antiviral therapy is available Sanitation Avoidance of questionable food and water in endemic regions Passive immunization Polyclonal anti-HAV antibodies that persist for 6 months Only effective for 2 weeks prior to exposure Expensive, painful, IM injection site reactions • Active immunization • a killed HAV vaccine • a live attenuated HAV vaccine

  21. Hepatitis B virus (HBV) • Baruch Blumberg, 1963: ‘Australian antigen - Au‘. • 1968: Au was a viral antigen = HBsAg (surface antigen)HAA • Dane, 1970: • Discovered 42nm 'Dane particles‘ • HBcAg (core antigen). • 1973: HBeAg discovered (endogenous antigen = a truncated version of HBcAg). • 1983: members of Hepadnaviridae

  22. Biological properties

  23. Electron microscopy of hepatitis B virus-positive serum reveals 3 morphologically distinct forms of particles tubular particle Dane particle (complete virion ) spherical particle (HBsAg)

  24. Dane particle-structure detergent HBeAg (also found in the soluble forms in virus-positive sera) (capsid)

  25. Dane particle-antigen • HBsAg • surface (coat) protein • “ a ” antigenic determinant ： 124-147aa • •4 phenotypes adw, adr, ayw, ayr • HBcAg • inner core protein • a single serotype • HBeAg • secreted protein • function unknown

  26. Genetic structure dsDNA (-) 3200 nt (+) 50-90% of (-) LEADING SEQUENCE DNA POLYMERASE cohesive terminus 粘性末端 DR 1: direct repeat (+) DR 2: direct repeat (-) 5’- TTCACCTCTGC

  27. Genetic structure(L-) • 4 open reading frames S, C, P, X regions P region overlap with S C P

  28. Genetic structure(L-) • S region: capsid protein • S gene: HBsAg • preS1 gene: preS1Ag • preS2 gene: preS2Ag SP1 promoter，2.4kb mRNA，large protein/大蛋白 SP2 promoter，2.1kb mRNA，middle protein/中蛋白& main protein主蛋白 HBV envelope proteins： − 主蛋白：HBsAg，S gene，226aa − 中蛋白：HBsAg+PreS2Ag，S+PreS2 gene，281aa − 大蛋白：HBsAg+PreS1Ag+PreS2Ag，S+PreS1 gene+PreS2 gene,400aa

  29. Genetic structure(L-) • C region • C gene: HBcAg • preC gene + C gene : HBeAg

  30. Genetic structure(L-) • P region: DNA polymerase (RDDP,DDDP, RNase H)

  31. Genetic structure(L-) • X region: HBxAg 0.8 kb mRNA trans-activation factor

  32. Genetic structure(L-) • 4 open reading frames • S region: capsid protein • S gene: HBsAg • preS1 gene: preS1Ag • preS2 gene: preS2Ag • C region • C gene: HBcAg • preC gene + C gene : HBeAg • P region: DNA polymerase • X region: HBxAg (trans-activation factor) (RDDP,DDDP, RNase H)

  33. replication 1. absorption, uncoating Pre S1, Pre S2 2. L-DNA → dsDNA DDDP 3. dsDNA(L-)→ mRNA DDRP 3.5kb, 2.4kb, 2.1kb, 0.7-0.9kb 3.5kb mRNA as template for DNA replication (pre-genome) 4. mRNA→ protein 3.5kb mRNA→ inner capsid proteins, DNA polymerase 2.4kb mRNA, 2.1kb mRNA→ outer capsid proteins 0.8kb mRNA→HBxAg 5. packaging of pre-genome and inner caspid & mRNA(pre-genome) →DNA(-) 6. DNA(-) → DNA(+) RNase H 7. virion packaging and release budding/exocytosis

  34. Genotype Variation >=8% nt seq A-H Genotype vs. serotype A adw B adw C adr, adw, ayr D ayw

  35. Variation HBV DNA polymerase: no proof-reading PreS/S gene Prec/C gene “a” eiptope mutation (nt in S gene encode for 145aa, 126aa ) e minus (A-G at1896nt in PreCgene ) e supression(1762/1764 ntmuationin promoter of PreCgene)

  36. Isolation and culture • Animal models: • Chimpanzee • Duck • Cell culture: not available • In vitro transfection

  37. Resistance Resistant to low temperature, dry, UV, 70% ethanol,ethyl ether, chloroform, phenol Dis-infected by 100 °C 10min, pH 2.4 6h Sensitive to detergent

  38. Pathogenesis

  39. Transmission Routes

  40. Concentration of Hepatitis B Virus in Various Body Fluids Low/Not High Moderate Detectable blood semen urine serum vaginal fluid feces wound exudates saliva sweat tears breastmilk

  41. Epidemiology • Estimated 300 million HBV carriers worldwide • High prevalence areas 10-20% • China, southeast Asia, sub-Saharan Africa • Intermediate prevalence areas 2-5% • Mediterranean, Middle East, Japan, Central and S. America • Low prevalence areas 0.1-2% • N. America, Europe, Australia, New Zealand

  42. Natural History of HBV Infection

  43. Balance between virus clearance and liver injury

  44. Immunopathogenesis • Virions released by exocytosis, not cytolytic • Ab-mediated immune responses • Type II hypersensitivity • Type III hypersensitivity • Cell-mediated immune responses • Type IV hypersensitivity

  45. HBV infection in infants and young children • Immature responses • mild symptoms, chronic infection (90%)

  46. HBV mutation and disease HBV pre-C mutation and chronic hepatitis HBV C mutation and fulminant暴发性的 hepatitis

More Related