Herpes and Pappillomavirus Flashcards
What type of genome do Herpes and Papillomavirus have?
dsDNA
What type of herpes virus causes oral herpes? How common is it? What is the outcome?
Usually type 1. Very Common. Resolution (but stays in body)
What type of herpes virus causes genital herpes? How common is it? What is the outcome?
Usually type 2. Common. Resolution (but stays in body)
How is HSV-1 transfered?
Oral-oral (SOMETIMES oral-genital)
How is HSV-2 transfered?
Primarily genital-genital (oral-genital also possible)
Symptoms of HSV?
Flu-like, includes localized lesions (virus spreading to neighboring cells)
How does HSV stay in the cell?
Genome circularizes and stays as an episome in the nucleus
What is a common site of latent HSV infections?
Peripheral ganglia
What type of immune response is required to battle HSV?
Cell mediated immune response (people unable to produce antibodies can still handle herpesvirus infections)
How does HSV counteract the immune response?
Viral proteins bind antibodies and complement proteins. Also counter the effects of interferon
What treatment options are available for HSV?
Acyclovir can limit virus replication (no effect on the latent infection)
What is a typical betaherpesvirus?
Cytomegalovirus (CMV)
What are some key characteristics of betaherpesvirus?
Restricted host range, long reproductive cycle, slow progression in cell culture, enlargement of infected cells, carrier cultures, latent infection in a variety of tissues.
What are some key characteristics of gammaherpesvirus?
Restricted host range, targets T & B lymphocytes, lytic infections, latency in lymphoid tissues
What is the prototypical member of gammaherpesviruses?
Epstein-Barr virus (EBV)
What type of disease do Beta/gammaherpesvirus disease commonly cause?
Mononucleosis
In equatorial Africa, what type of disease does Epstein Barr virus typically cause in children?
Burkett’s lymphoma. Tumor in jaw, eye socket, ovaries
What is Hodgkin’s lymphoma caused by?
Caused by Beta/gammaherpesvirus (specifically EBV)
What are intrinsic immune evasion tactics of herpes viruses?
Inside the cell. Block cell death/inhibit apoptosis
What are innate immune evasion tactics of herpes viruses?
Decrease NK cell activity and inhibit NK receptor activation
What are adaptive immune evasion tactics on herpes viruses?
- Decreased antigen presentation, 2. Degrade MHC class I and II, 3. Blocks MHC class II and T-cell receptor Interactions
What is the only type of Herpes virus that does not have innate immune evasion tactics?
EBV does not decrease NK cell activity or inhibit NK receptor activation.
What is a persistant infection?
Viral cells are constantly reproducing and host immune system is suppressing it. Differs from latency in that there is a rest period with a latent infection
What treatment options are available for Beta/gammaherpesvirus?
- Passive transfer of antibodies for prevention of CMV infection, 2. Trasfer of EBV-specific T-lymphocytes, 3. Antiviral Therapy - Prophylactic or preemtive treatment
What family of viruses does HPV belong to?
Papillomaviridae
What type of genome does HPV have?
circular dsDNA
What type of virion does HPV have?
non-enveloped
Where does HPV establish an infection?
Basal layer of skin
What does HPV require from host cell?
Polymerase in differentiating cells
How is HPV spread?
It is non-lytic, so virus is released with dead cell shedding
How does HPV enter a host?
Direct skin-to-skin contact; Mucous membranes are more suseptible; Enters through abrasions
What can be a complication of HPV?
HPV can lead to cervical cancer.
How does HPV cause cervical cancer?
E7 blocks Rb protein leading to continued cell proliferation; E6 blocks p53 tumor suppressor pathway_.Note: actual path is unknown
What types of HPV are most responsible for cervical cancer?
HPV16 and HPV18
What prevention is possible for HPV?
Vaccination - Gardasil (Merck) protects against HPV 6, 11, 16, 18; No proof that condoms reduce risk
