6. CLASSIFICATION
• GENERA…..4
• 1 Mastadenovirus; human 51 antigenic types
• Six groups; A-F.
• physical, chemical, biological. genetic basis
• Fibres
• DNA homology; G & C content
• Agglutinate RBC; monkey, rats
7. REPLICATION
• Replicate only in cells of epitheleal origin
• Early genes…..throughout
• Intermediate genes
• Late genes
VIRAL Attachment
1 via fibre
2 receptor; CAR ( coxsackie virus receptor)
3 internalization in endosomes, then cytosol,
uncoating , nuclear memb. DNA release
8. EARLY EVENTS
• Host cell enters S phase
• ‘E’ early transcripts from 7 regions of both
strands E1A & E1B involved
• 20 early non-structural proteins made for viral
DNA replication
• LATE EVENTS
• DNA SYNTHESIS
• Structural proteins made; large primary transcript
• 29000 nucleotides; 18 mRNA spliced to
cytoplasm for viral protein synthesis.
9. VIRAL ASSEMBLY, MATURATION
• Morphogenesis in nucleus: 24 hrs/ 10,000 virion
made/cell
• 3 identical Polypeptides…..
• Hexon capsomere
• Penton…. 5 base polypeptides/ 3 fibre pp
• Capsomeres self assemble as empty capsids in
nucleus
• Naked DNA enters capsids
• Mature particle: stable, infectious, resistant to
nucleases
13. Virus effect on host defense
• Encode gene products that counter anti-viral
mechanisms
• VA RNA ……counter interferon
• E3 region proteins….prevent cell lysis by host
response
14. VIRUS EFFECTS ON CELLS
• CYTOPATHIC….. Human cell cultures;
• kidney,
• continuous epithileal cells
• Rounding, enlargement and clustering of cells
• No lysis
• Intranuclear lesions seen
• Crystalline look due to protein
• Viri remain in celll even after death of cell
15. GENE THERAPY
Gene delivery vehicles for
• cancer therapy; oncolytic therapy…kill cell by
viral rep.
• gene therapy,
• genetic immunization
Limitation:
• CAR : variable expression in various cells
• Failure to integrate in chromosomal DNA
16.
17. Transforming genes
• Serotypes 12,18, 31 induce tumors in
newborn hamsters
• Al ADV transform cell in culture
• Transforming genes in E1A & EIB
• Alter growth control mechanisms
• Type 12 stops synthesis of class 1 MHC, no
destruction by CTLs
18. PATHOGENESIS: TYPE 1-7
• Epitheleal cells :
• RT: 5% in children, mild
• GIT
• EYE
• UT
• Limit by regional LN
• Group C persist in adenoids & tonsils
19. RESPIRATORY; Group C
Children:
• Cough, nasal cong, fever, sore throat;
• Pneumonias(3,7 21); childhood;
• mortality 10-20%
• Military recruits;
• all above in fatigue, stress, crowding( type4,7)
20.
21. Eye infection
• 1. Children summer camps
• Swimming pool conjunctivitis( type 3.7)
• Recovery in 1-2 weeks
• 2. epidemic keratoconjunctivitus(8,19,37)
• Adults
• contageous,
• resolves in 2 weeks;
• may leave opacities in cornea
25. Prevention
• Hand wash
• Disinfection
• Chlorination
• Equipment sterilization
• Paper towels
• LIVE VACCINE:1971
• Type 4 &7 in gelatin capsules orally
• Induce Nt AB
26. immunity
• Effective
• Long lasting due to LN involvement
• Neutralizing AB; life long
• Maternal protection
27. LAB DIAGOSIS
SWABS: stool, urine , throat, rectal
Diagnosis of current infection: eye, lung, genital tract
1CULTURE: Human cells: embryonic kidney, HeLa, KB
• IF AB used on cells ; anti-hexon AB
• HI & Nt used
2 Nasal epith. Cells stained directly to see Ag
3. PCR; fluids, tissue; conseved seq; hexon, VA1
4. DNA hybridization; restriction endonucleases
5. feces; electron mic, ELIZA; Latex Agg,
Inconclusive unless GE present in pt
28. SEROLOGY
• Complement –Fixing: AV group Ag
• AB 4 fold rise in sera of acute---convalascent
sera
• Neutralizing anti-body; most sensitivite
• 4* rise
• HI
29. epidemiology
• Global, all year round
• Resp Tract: low no 1,2,3,5,7 serotypes; 2-5%
• Military; 3,4,7
• Gastro-Entritis; 40,41
• Spread; direct contact, contaminated fomites
• feco-oral, aerosol
• Infant: 1,2,5,6
• School; 3,7
• Adult; 4,8,19
• Eye: hand to eye
• water, swimming pools 3,7
