4.3 Flashcards
Viral Infections
Antigenic drift
Changes in antigen due to mutations and modifications in the pathogen; errors in replication and lack of repair mechanisms
*“Drifting along water”, gradual change overtime
Antigenic shift
reassortment of genetic materials when concurrent infection of different strains occurs in the same host
*Two different strains affect organism and create something new
*Massive, sudden change that occurs during co-infection
Cytopathic Effects (CPE)
Viral induced damage to the infected cells that alters their microscopic appearance
Types of CPE include:
- Nuclear and cytoplasmic inclusion bodies/granules
- Syncytia formation (multi-nucleated giant cells)
- Nuclear alterations
- Cell rounding and death
Active Infection
Cell lysis –> leads to acute infection
- Viral infection short lived, cell death
typically results in strong immune
response and fast clearance of pathogen
Chronic/Persistant Infection
Budding
- Viral infection long term, some means of
evasion or lack of cell death results in weak
immune response and little clearance
Latent Infection
Genetic material put into chromosome
- Back and forth btwn active and latent
- Initial acute period but then becomes asymptomatic
- Reactivation of virus typically during times of
stress or weakened immune system
Indirectly
create/alters environment in the infected cell or tissue that makes it more likely that loss of proliferation control will occur
*HIV targets T-cells
Directly
targets cell division; cause increased/uncontrolled proliferation of infected cells, leading to tumor formation
*HPV
Human papillomavirus (HPV) cancer
E7 and E6
E7
blocks pRB (tumor suppressor) and cell loses cell growth inhibition signal (all cells have growth signal)
E6
blocks p53 (massive tumor suppressor) and cell loses apoptotic abilities and response to DNA damage
AND activates telomerase so cell has endless replicative potential
