Papovaviruses
Papovaviruses
Papovaviruses
(Papovaviridae) :
Papillomaviruses and
Polyomaviruses
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02/25/23 1
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PAPOVAVIRIDAE
• Name from: Papilloma Polyoma Vacuolating agent
• Warts
• human cancer (e.g., cervical and penile
carcinoma):
– several genotypes over 100 strains
•double-stranded •double-stranded
•circular DNA •circular DNA
Genom
e •~5kbp •~8kbp
•genome ~5000 •Genome ~ 8000 nucleotides
nucleotides
•Noneveloped •Nonenveloped
Morpho
logy •~45 nm diameter •~52-55nm diameter
•icosohedral, skew, T= 7 •icosohedral, skew, T= 7
•3 capsid proteins •2 capsid proteins
Other
Differen •Subfamily specific antigens
ces •Papillomavirus can't be grown in culture, while polyomaviruses are often grown in culture
Repres JC Virus
entative •Associated with Progressive multifocal
At least 62 strains of Human Papillomaviruses
Viruses leukoencephalopathy, found mainly in •Widespread
the elderly and immunocompromised
BK Virus •Cause growths or warts
•Results in mild respiratory illness in
kids •Many are associated with cancer
•Found in some tumors
Ssuuna Charles PG-MCB-MUST MLSO-
Simian Virus 40
02/25/23
A completely sequenced animal virus used 5
frequently as a cloning vector.
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Unique Properties of Polyomaviruses and
Papillomaviruses
• lytic infections
Disease/Viral Factors
•Capsid virus is resistant to inactivation
•Virus persists in host
•Asymptomatic shedding is likely
Transmission
•Papillomavirus: direct contact, sexual contact
(sexually transmitted disease) for certain virus
types, or passage through infected birth canal for
laryngeal papillomas (types 6 and 11)
•Polyomavirus: inhalation or contact with
contaminated water
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Epidemiology of Polyomaviruses and Papillomaviruses
Who Is at Risk?
– smoking
– immunosuppression
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HPV diseases
• Cutaneous Syndromes
• Skin warts HPV1 through HPV4
• Mucosal Syndromes
• Benign head and neck tumors
• Laryngeal papilloma
• Oral papilloma
• Conjunctival papilloma
• Anogenital warts
• Condyloma acuminatum 6, 11
• Cervical intraepithelial neoplasia, cancer16, 18
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02/25/23 18
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02/25/23 19
MDLC Downloaded from: StudentConsult (on 11 May 2009 01:13 PM)
© 2005 Elsevier
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02/25/23 20
MDLC Downloaded from: StudentConsult (on 11 May 2009 01:13 PM)
© 2005 Elsevier
Papillomaviruses infect squamous epithelial cells and induce
within those cells a characteristic cytoplasmic vacuole.
These vacuolated cells, called koilocytes, are the hallmark of
infection by these viruses.
Most warts are benign and do not progress to malignancy.
The proteins encoded by viral genes E6 and E7 interfere with the
growth-inhibitory activity of the proteins encoded by the p53 and
RB tumor suppressor genes and thereby contribute to oncogenesis
by these viruses.