Chapter 22Chapter 22

pathogen of viral hepatitis

IntroductionIntroduction1. Human hepatitis viruses1. Human hepatitis viruses

HAV(+ssRNA) , HBV(dsDNA), HCV(+ssRNA) , HDV(–ssRNA) and HEV(+ssRNA)

HGV(+ssRNA) and TTV(–ssDNA)

2.Other viruses of causing2.Other viruses of causing viral hepatitisviral hepatitis(CMV,EBV,Rubella virus,VZV,Yellow fever virus,etc.)

**pathogen of hepatitis type A **classified as Hepatornaviridae ( 肝 RNA 病毒属 )

1. Shape and structure 1. Shape and structure

•spherical particle(d=27nm)

•icosahedral nucleocapsid

•ssRNA (positive stranded) •can code for polyprotein,RNA polymerase and proteinase

VP1-4

GenomeGenome

Naked virusNaked virus

↓ Cleave4 polypeptide (VP1 to VP4) ↓ capsomere→capsid

capsomere

ⅠⅠ.Biological Properties.Biological Properties

infective model(( 黑猩猩、狨猴、红面猴黑猩猩、狨猴、红面猴 )) cell culture (( 原代肝细胞或恒河猴胚肾传代细胞原代肝细胞或恒河猴胚肾传代细胞 ))

stable to treatment with ether( 乙醚 ), acid (PH3) and heat (60 for 1 hour)℃(60 for 1 hour)℃ tolerate boiling for 5 minutes

2.Resistance2.Resistance

3.Cultivation3.Cultivation

(multiply slowly, non-CPE)(multiply slowly, non-CPE)

Antigenicity ofAntigenicity of capsid protein:HAV-Agcapsid protein:HAV-Ag(only one serotype)(only one serotype)

1.Pathogenicity1.Pathogenicity Source of infectionSource of infection

Route of transmissionRoute of transmission

•asymptomatic or only mildly ill •acute hepatitis of short incubation •fulminant hepatitis and favorable prognosis

Feature of HAV-infectionFeature of HAV-infection

by fecal-oral route ( 通过粪 - 口途径传播 )

罕见暴发性肝炎罕见暴发性肝炎 ,, 预后良好预后良好

很常见很常见

罕见慢肝和携带者罕见慢肝和携带者

ⅡⅡ.Pathogenicity and Immunity.Pathogenicity and Immunity

2.Pathogenesis2.Pathogenesis

Immunopathogenesis Damage caused by HAV ?

Virus Virus in fecesin feces

Intestine and localIntestine and locallymphoid tissuelymphoid tissue

bloodblood

(replication)

liverliver

by fecal-oral route( 污染食物和水 )

通过日常生活接触→散发性肝炎通过污染食物和水→肝炎的暴发流行

3.Immunity3.Immunity3.Immunity3.Immunity

IgM anti-HAVIgM anti-HAV++---recent infection---recent infection antibody to HAVantibody to HAV(IgG---lifetime persistence)

------long-lasting immunitylong-lasting immunity

virus in blood

ⅢⅢ.Laboratory Diagnosis.Laboratory Diagnosis1.Detection of viral antibody1.Detection of viral antibody

2.Detection of virus particles in feces2.Detection of virus particles in feces(IEM)

IgM anti-HAV （ ELISA, 早期诊断） IgG anti-HAV （ ELISA ，既往感染 / 流调）

3.Detection of viral RNA3.Detection of viral RNA

ⅣⅣ.Specific Prevention.Specific Prevention1.Artificial active immunity1.Artificial active immunity

2.Artificial passive immunity2.Artificial passive immunity(vaccine---strain H2 )

(gamma globulin ）

Pathogen of hepatitis B

Shape Shape

• larger spherical particlelarger spherical particle

• small spherical particlesmall spherical particle

• tubular particle/filamentstubular particle/filaments

virion of HBV, i.e. Dane particle virion of HBV, i.e. Dane particle

1.Shape and structure1.Shape and structure

1:1730:120

in the blood of patients with HB

---three viral particle in the blood of infected persons

42 nm

ⅠⅠ.Biological Properties.Biological Properties

Structure of virionStructure of virion ---Spherical particle with double-shelled capsid

⑵⑵viral core---nucleocapsidviral core---nucleocapsid

• surface---inner shell

• core

HBcAg

dsDNA

DNA polymerase

(d=27nm)

(contains HBsAg, Pre-S1 and Pre-S2 Ag)

(contain HBcAg and HBeAg)(contain HBcAg and HBeAg)

*ds-DNA*ds-DNA*DNA polymerase*DNA polymerase

*Protein kinase*Protein kinase

⑴⑴ outer shell outer shell

d=42nm

core27nm

protein kinase

HBsAg

-DNA-DNA+DNA+DNA

DR2DR2DR1DR1

XX

Pre-CPre-C

CC

SS

Pre-S2Pre-S2Pre-S1

PP

Circular ds-DNACircular ds-DNA (has a single-chain region)

–DNA

+DNA

Sticky end & Sticky end & direct repeat (DR1,2)direct repeat (DR1,2)

2.2. Genome structureGenome structure

5‘5‘

•long chain---completelong chain---complete •4 ORF 4 ORF (open reading frames) (open reading frames)

(short chain (short chain --- ---variable length)variable length)

(DNA 成环和病毒复制的关键序列 )

Unique mode of replicationUnique mode of replication 3.Replication of HBV3.Replication of HBV

---retrovirus-like pathway of replication

Replicative cycleReplicative cycle (p287 Figure 22-5)

dsDNA

cccDNA

3.5kbRNA

外衣壳蛋白（ HBsAg ）

内衣壳蛋白（ HBcAg ）

2.1kbRNA转录RNAP

作为m

RNA转译

转译

前基因组 与 DNAP 进入内衣壳 逆转录

-DNA复制

+DNA

dsDNA

子代 HBV

DNA 多聚酶

与负链结合

完整的环状 ds-DNA

4.Compositions of antigen4.Compositions of antigen

Hepatitis B surface antigenHepatitis B surface antigen (HBsAg)

Hepatitis B core antigenHepatitis B core antigen(HBcAg)

Hepatitis B e antigenHepatitis B e antigen(HBeAg)

Other antigenOther antigen (Pre-S1, Pre-S2 antigen, HBxAg)

⑴ ⑴Exist in blood from infected personExist in blood from infected person with HBVwith HBV • outer shell of Dane particle• small spherical particle• tubular particle

HBsAgHBsAg

HBsAg

⑵ ⑵ Subtypes of HBsAgSubtypes of HBsAg

⑶⑶ HBsAgHBsAg++---marker of HBV infection---marker of HBV infection

⑷⑷ Anti-HBs:neutralizing antibodyAnti-HBs:neutralizing antibody

• contains common epitope a , subtype epitope d/y and w/r• 4 major subtypes subtypes ---- adr , adw , ayr , ayw

• 具有免疫保护作用• 抗 -HBs+ 表示感染过 / 患病已恢复 / 接种过疫苗获得免疫力

HBcAgHBcAg ⑴ ⑴Locate in surface of viral coreLocate in surface of viral core

⑵⑵Anti-HBcAnti-HBc++---marker of viral infect---marker of viral infection and replicationion and replication• IgM anti-HBc++ ---active replication of HBV

• IgG anti-HBc++ ---past infection

(cann’t find in serum)

*marker of recent infection *marker of recent infection

* *high titers---marker of acute hepatitis high titers---marker of acute hepatitis BB

(non-neutralizing Ab)(non-neutralizing Ab)

HBeAgHBeAg⑴⑴Exist in HBsAg-positive serumExist in HBsAg-positive serum

⑵⑵Associated with presence of Dane paAssociated with presence of Dane particles and DNAPrticles and DNAP

⑶⑶HBeAgHBeAg++---marker of virus replication ---marker of virus replication and high infectivity of serum and high infectivity of serum

⑷⑷Anti-Anti-HBeHBe+ +

----marker of lower infectivity----marker of lower infectivity

5.Animal model and cell culture5.Animal model and cell culture5.Animal model and cell culture5.Animal model and cell culture

6.Resistance of HBV6.Resistance of HBV•• stable to heat (60 for 4 hour) ℃(60 for 4 hour) ℃ •• disinfectant ( 常用 0.5% 过氧乙酸和 5%

次氯酸钠 )) •• 高压灭菌法、 100 ℃加热 10 分钟和环氧乙烷可灭活病毒

Source of infectionSource of infection Source of infectionSource of infection •patients with hepatitis B •asymptomatic HBsAg carrier(( 无症状无症状 HBsAgHBsAg 携带者携带者 ,ASC),ASC)

1.Pathogenicity1.Pathogenicity

Route of transmissionRoute of transmission•via infected blood or blood products •vertical transmission

杜绝医源性传播杜绝医源性传播 !!

ⅡⅡ.Pathogenicity and Immunity.Pathogenicity and Immunity

Feature of HBV-infectionFeature of HBV-infection•Diversity of clinical finding

•prognosis**progress toward choronic progress toward choronic (10%)(10%) * * leading to hepatocirrhosisleading to hepatocirrhosis**often associated with primary often associated with primary hepatocellular carcinomahepatocellular carcinoma

•Long incubation hepatitis---ASC, acute/chronic or fulminant hepatitis---ASC, acute/chronic or fulminant hepatitis

•Liver damage is caused by thehost immunologic response

（肝硬化）

（原发性肝细胞癌）

PathogenesisPathogenesis---liver damage is caused by the host immunologic response⑴⑴immunopathogenic damage mediated by cellimmunopathogenic damage mediated by cell

ular immunityular immunity ⑵ ⑵pathogenic damage caused by IC pathogenic damage caused by IC ⑶ ⑶pathogenic damage caused by autoimmupathogenic damage caused by autoimmunitynity

⑷⑷immune tolerance & chronic hepatitis immune tolerance & chronic hepatitis viral variation & immune escape ⑸viral variation & immune escape ⑸

(CTL,CD4+T;CKs→→→ 急性、慢性、重症肝炎和肝硬化 )

（重症肝炎以及肝外症状）

(LSP→ 慢迁肝和慢活肝 )

2.Immunity2.ImmunitySpecific humoral immunitySpecific humoral immunity

Specific cellular immunitySpecific cellular immunity

---neutralization of anti-HBs ( 清除血中的游离病毒 )

---double effects mediated by CTL • 免疫保护作用免疫保护作用 ------ 清除细胞内病毒清除细胞内病毒

• 免疫损伤作用免疫损伤作用 ------ 参与致病作用参与致病作用

抗抗 -PreS1-PreS1 、抗、抗 Pre-S2Pre-S2 也有保护作用也有保护作用

3.HBV & primary 3.HBV & primary hepatocellular carcinoma hepatocellular carcinoma

Ⅲ.Laboratory Diagnosis1.1. Detection of viral antigens and Detection of viral antigens and antibodysantibodys

(“(“ 二对半”的检测二对半”的检测 ))

Including : HBsAg, anti-HBs , anti-HBc, HBeAg and anti-Hbe

Methods : ELISA or RIAELISA or RIA Clinical analysis and signification

二对半检测结果的临床分析HBsAg HBeAg anti-HBs anti-HBe anti-HBc 结果分析

+ – – – – HBV 感染者或 ASC

+ + – – – 急性 / 慢性肝炎或 ASC (( 传染性强传染性强 ) )

+ + – – + 急性 / 慢性肝炎或 ASC (( 传染性强传染性强 ))

+ – – + + 急性感染趋向恢复 – – + + + 既往感染恢复期 – – + + – 既往感染恢复期 – – – – + 既往感染 / 窗口期– – + – – 对再感染有免疫力 (( 恢复期、既往感染或接种过疫恢复期、既往感染或接种过疫苗苗 ))

p291

“ 小三阳”

““ 大三阳大三阳””

““ 二对半”的检测的实际应用二对半”的检测的实际应用⑴⑴ 特异性诊断 特异性诊断

⑵⑵ 筛选供血者 筛选供血者

⑶⑶ 判断病人、判断病人、 ASCASC 和孕妇和孕妇的传染性的传染性

⑷⑷ 估计病人的转归和预后估计病人的转归和预后

⑸⑸ 流行病学调查与追踪传染流行病学调查与追踪传染源 源

⑹⑹ 确定母婴传播阻断对象确定母婴传播阻断对象

“ 大三阳” , IgM 抗 -HBc+ ; HBsAg 单项阳性(ASC)

筛去 HBsAg+, 抗 -HBc+

HBsAg+ 伴 HBeAg+

•HBsAg+ 与 HBeAg+ 在2 个月内阴转—好 •“大三阳”持续 6 个月以上 --- 慢性转化 •慢活肝 HBeAg 一旦 消失示病情好转

( 抗 -HBs 和 HBsAg 及其亚型的检测 )

2.Detection of HBV-DNA2.Detection of HBV-DNAHBV-DNA+---- 病毒正在复制 , 其血清传染性强

ⅣⅣ.Principle of prevention.Principle of prevention

1.General prevention1.General prevention

2.Specific prevention2.Specific prevention Artificial active immunity Artificial passive immunity Passive-active immunity

(HBIg)(HBIg)

(HBIg+vaccine)(HBIg+vaccine)

vaccinevaccine

1.General properties1.General properties 30-60nm spherical particle, enveloped virus Genome structure ( p297) ---linear ss-RNA (positive strand)

2.Pathogenicity2.Pathogenicity Souse of infection Route of transmission Cause hepatitis C

血源性传播为主血源性传播为主非经血传播→散发性丙肝血源性传播→输血后丙肝

患者或慢性携带者患者或慢性携带者

Feature of HCV-infectionFeature of HCV-infection•• asymptomatic, acute hepatitis and chronic hepatitis

• • cause extrahepatic damage

• • prognosis*progress to hepatocirrhosis (20%) *progress to hepatocirrhosis (20%)

*often associated with primary cellular carcinoma*often associated with primary cellular carcinoma

(40% ~ 50%)(40% ~ 50%)肾小球肾炎

3.Diagnosis3.Diagnosis

4.Prevention4.Prevention

--- detection of HCV-RNA and anti-HCV抗抗 -HCV+-HCV+ 表示已感染表示已感染 HCV (HCV ( 不可献血不可献血 ))

Stop iatrogenic transmission!!! Stop iatrogenic transmission!!! 严格筛选供血者严格筛选供血者 ,,使用灭活的血制品使用灭活的血制品

1.Shape & structure1.Shape & structure Shape Shape structurestructure

35-37 nm

HDAg

RNA HBsAg

*genome:*genome: circular –ssRNAcircular –ssRNA*HDAg*HDAg ( P24,P27)( P24,P27)

•capsid:HBsAg •viral core

(helper virus: HBV)(helper virus: HBV)HDV--- defective virusHDV--- defective virus

2.Pathogenicity2.Pathogenicity Hematogenic transmissionHematogenic transmission Cause acute hepatitis D Cause acute hepatitis D

•coinfection (( 联合感染或共同感染联合感染或共同感染 ))

•superinfection(( 重叠感染重叠感染 ))

3.Diagnosis3.Diagnosis (detection of anti-HD, HD-Ag detection of anti-HD, HD-Ag and HDV-RNA)and HDV-RNA)

1.Shape & structure1.Shape & structure ShapeShape

•32-34nm spherical particle•naked virus with appearance of a calicine

Genome Genome

--- +ssRNA (p301 Figure 29-11)

形似杯状

2.Pathogenicity2.PathogenicityRoute of transmissionRoute of transmission

Cause acute hepatitis E

3.Diagnosis3.Diagnosis

(detection of HEV-RNA and anti-HEV)

水源污染→暴发流行水源污染→暴发流行

流行及临床似甲肝

(by fecal-oral route)