Ch21 Flashcards
(36 cards)
What was the original family name that included both papillomaviruses and polyomaviruses?
Papovaviridae (now split into Papillomaviridae and Polyomaviridae).
What are the key diseases caused by Papillomaviridae (e.g., HPV)?
Warts and cancers like cervical carcinoma.
What diseases are associated with Polyomaviridae viruses like JCV and BKV?
• JCV: Progressive multifocal leukoencephalopathy (PML).
• BKV: Nephropathy, especially after kidney transplant.
What do Papillomaviridae and Polyomaviridae have in common structurally?
• Non-enveloped
• Icosahedral capsid
• Circular double-stranded DNA genome
What viral proteins are involved in the oncogenic potential of these viruses?
• HPV: E6 and E7 proteins
• Polyomaviruses: T antigen
What are the target cells of HPV?
Keratinocytes in the basal epithelial layer.
How does HPV enter the body?
Through small breaks in the skin or mucosal surfaces.
What is the role of early genes in HPV infection?
They promote cell proliferation (increase cell division).
When are late genes of HPV expressed?
terminally differentiated (mature) epithelial cells.
Where does virion assembly occur in HPV infection?
In the upper layers of the epidermis.
What does the HPV E7 protein do?
It inactivates RB, leading to uncontrolled cell cycle progression.
What is the function of the HPV E6 protein?
It degrades p53, preventing apoptosis.
How does the HPV E5 protein contribute to infection?
It enhances EGFR signaling to promote cell growth.
What are the outcomes of HPV infection in epithelial cells?
t can cause benign warts and potentially progress to cancer, such as cervical squamous cell carcinoma (SCC).
How is HPV transmitted?
Through direct contact, sexual contact, and perinatally (from mother to baby at birth).
What are major risk factors for HPV infection and progression to cancer?
Multiple sexual partners, smoking, and immunosuppression.
Which HPV types cause cutaneous warts (on hands and feet)?
HPV types 1–4
Which HPV types cause anogenital warts (condyloma acuminata)?
HPV types 6 and 11.
Which HPV types are most commonly linked to cervical cancer?
HPV types 16 and 18.
What types of cancer can HPV cause?
Cervical, oropharyngeal, anal, penile, vaginal, and vulvar cancers.
What test detects koilocytes and is used to screen for HPV-related changes?
Pap smear.
What molecular test is used to detect HPV DNA?
PCR or RT-PCR.
What are common treatments for HPV warts?
Cryotherapy, imiquimod, and cidofovir.
What treatment is used for laryngeal papillomas caused by HPV?
Surgery
