3. Viral Immunology Flashcards
(34 cards)
what is the first thing that tells the body that a viral infection is coming
type I interferon
do innate or adaptive responses occur on initial exposure
innate
do innate or adaptive responses occur upon secondary exposure
adaptive
what are some examples of physical barriers
skin
mucus
stomach acidity
which cells respond second to a virus
NK cells
(type I interferon 1st)
what do pattern recognition receptors (PRR) do
they recognize patterns on pathogens (pathogen associated molecular pattern PAMP)
what is most important in the type I interferon response
activating a large number of proteins that have antiviral properties
how do NK cells stop viral spread
kill infected cells
- can recognize cells that have down-regulated their MHCI
which cells are essential in bridging the innate and adaptive responses
macrophages and dendritic cells
what do plasmacytoid DCs so
make large amounts of type I interferon in a viral infection
- they can sense a viral infection without being actively infected
- no active infection means most of the ways the virus has to stop interferon production will not work in plasmacytoid DC
which antibodies are a critical part of the adaptive immune response
neutralizing antibodies
viral antigens encountered in the mucosa primarily produce which Ig
dimeric IgA
-produced in large quantities in the mucosal surfaces, gut, and upper and lower respiratory tract
viruses that have a viremic stage (virus in the blood) primarily produce which Ig
IgG
the second critical adaptive response in viral infection is the activation of which cells
cytotoxic T lymphocytes (CTLs)
- they kill infected cells and are important in keeping chronic viral infections in check
what are the 5 ways viruses can subvert the immune system
- “hide” - latency
- escape neutralization antibodies by antigenic drift
- block the type I interferon response
- downregulating MHC I which prevents killing by CTLs
- killing immune cells - like HIV killing CD4 cells
T/F if you encounter the same strain of the virus, you are generally protected from reinfection
True
if you encounter the same strain of the virus, you are generally protected from reinfection due to what?
long-lived plasma cells and secreted antibodies
when encountering the same strain of virus, are the neutralizing antibodies present in your mucosa and blood before re-encountering the virus or are they produced once the virus is re-encountered
the neutralizing antibodies are present in your mucosa and blood before re-encountering the virus
define cross-protecting when encountering a different strain of the virus
the new strain is recognized with good affinity by antibodies from a previous strain, resulting in no infection or sickness
define partial cross-protection when encountering a different strain of the virus
antibodies bind with lower affinity. as a result, the antibodies cannot prevent some cells from being infect. the infection will generally clear faster, and there might be fewer symptoms because you will get helpful neutralizing antibodies quicker than in a primary infection. This will result in less spread of the virus. also, the memory CTLs from the previous infection might be able to recognize and clear the infected cells, reducing the infection’s severity
define no cross-protection when encountering a different strain of the virus z
it is like a new infection
what are the two things that you need to get an effective vaccine
- need to induce a protective neutralizing antibody response to the virus
- stimulate an immune response
what are the three kind of vaccines
attenuated virus vaccines
whole killed virus/inactivated virus
subunit vaccine
how do attenuated virus vaccines work
attenuated viruses replicate just a little
- immune system sees it as a regular viral infection and mounts an immune response (which clears the infection before you get sick)
- theses tend to be excellent vaccines
