Subversion and Evasion of the Immune System Flashcards
What are opportunistic organisms?
Part of the normal flora that will invade the host cause disease if given the chance due to immunological dysfunction, etc.
What is a serotype of an organism?
A subclassification of species based on the microbial capsule and carbohydrates on it
True or False: Having immunity to one serotype means having immunity to all serotypes.
False
What is antigenic shift and antigenic drift?
Shift- major reorganization of viral genetic material e.g., thorough exchange between two different viruses; Drift is the little changes in the viral RNA that accumulate each time it replicates
What is gene conversion? What blood borne parasite uses this technique?
There are many potential genes for surface antigens that can get swapped into the expression ‘cassette’ or site; Trypanosomes
What are the general ways in which a pathogen can directly attack or repurpose the immune system?
Inhibiting humoral immunity, inhibiting the inflammatory response, blocking antigen processing and presentation,, suppression of the host, superantigens
What kind of virus is HIV? What type of cells are infected?
Retrovirus; CD4+ T cells
What are the HIV structures that can serve as immune targets?
Viral envelope proteins (gp120, gp41), and intracellular proteins/RNA
How does HIV gain entry into the cell?
Using the Env proteins it binds to CD40 and either CCR5 (mostly) or another coreceptor
Once a CD4+ cell becomes a provirus what are the two paths it can take?
If it is inactive, the provirus will not be expressed and hide within the genome; If it is active it will become a cytolytic infection
What are neoantigens?
Antigens made through mutations which have not been encountered by the immune system and are not seen as self
What are some mechanisms by which tumor cells evade immune surveillance?
Downregulation of MHC I, Secretion of anti-inflmmatory and immune regulatory molecules (including TGFb), or by inhibiting T cell immmunity (e.g., through expression of CTLA4)
