L7 Flashcards
- Herpes Simplex Virus Type 1 (HSV-1)
- family
Alphaherpesviridae
*Herpes Simplex Virus Type 1 (HSV-1)
genome
dsDNA
*Herpes Simplex Virus Type 1 (HSV-1)
virion
Enveloped
*Herpes Simplex Virus Type 2 (HSV-2)
Family
Alphaherpesviridae
*Herpes Simplex Virus Type 2 (HSV-2)
genome
dsDNA
*Herpes Simplex Virus Type 2 (HSV-2)
virion
Enveloped
Cytomegalovirus family
Betaherpesviridae
Cytomegalovirus genome
dsDNA
Cytomegalovirus virion
Enveloped
Epstein-Barr virus
family
Gammaherpesviridae
Epstein-Barr virus
genome
dsDNA
Epstein-Barr virus
virion
Enveloped
Human Papillomavirus
family
Papillomaviridae
Human Papillomavirus
genome
dsDNA
Human Papillomavirus
virion
nonEnveloped
Alphaherpesvirus Variable
host range
Alphaherpesvirus Short
reproduction cycle
Alphaherpesvirus Rapid spread in
culture
Alphaherpesvirus Efficient destruction of
infected cells
Alphaherpesvirus Capacity to establish
latency in sensory ganglia
Alphaherpesvirus Infection
HSV-1 Oral-oral, oral-genital Nearly 2/3 adults are seropositive HSV-2 Primarily genital-genital, oral-genital also possible More prevalent with sexual activity Approximately 1/5 adults are infected Primarily infect epithelial cells in the skin or mucosa; mucosa are more susceptible
Alphaherpesvirus Incubation
HSV-1&2: 2 – 14 days, typically 4 – 5 days
Alphaherpesvirus Symptoms
Flu-like, includes localized lesions (virus spreads to neighboring cells primarily)
Only 1/3 show symptoms
Asymptomatic can still transmit
Last for 8 to 12 days
Alphaherpesvirus Latency
Stationary cells, genome circularizes and stays as an episome in the nucleus
Peripheral ganglia common site of latent infections
Triggers: sunburn, systemic infection,immune impairment,stress
Cell mediated immune response required
Alphaherpesvirus
People unable to produce antibodies can still handle herpesvirus infections T lymphocytes detect antigens presented by MHC class I or II proteins
Alphaherpesvirus Modulation of the immune response
Viral proteins bind antibodies and complement proteins
Counter effects of interferon
Alphaherpesvirus Prevention
Avoid contact (e.g., kissing, sex) during active herpes recurrence
Alphaherpesvirus treatment
Acyclovir can be used to limit virus replication
Will not eliminate latent infections
Betaherpesvirus
Restricted host range
Long reproductive cycle
Slow progression in cell culture
Betaherpesvirus Enlargement of
infected cells (cytomeglia)
Betaherpesvirus
Carrier cultures
Latent infection in a variety of tissues
Prototypical member: Cytomegalovirus (CMV)
Gammaherpesvirus key characteristics
Restricted host range Targets T & B lymphocytes Lytic infections Latency in lymphoid tissues Prototypical member: Epstein-Barr virus (EBV)
Beta/gammaherpesvirus Disease (Cont.)
EBV associated carcinomas
Burkett’s lymphoma
Beta/gammaherpesvirus Disease (Cont.)
Most common childhood cancer in equatorial Africa
Tumor in jaw, eye socket, ovaries
In all cases, tumor cells have monoclonal EBV episome
Role of EBV still not understood
Spur B cell growth, mutations, or
Genes transform cells
Beta/gammaherpesvirus Disease
EBV associated carcinomas (Cont.)
Hodgkin’s lymphoma
Hodgkins lymphoma
Three types
NL – nodular sclerosing
MC – mixed cellularity
LD – lymphocyte depleted
EBV present in 60% to 90% of MC & LD tumors, 20% to 40% of NL tumors
Exact role of EBV unknown