Immunity Flashcards
1
Q
how can a person develop autoimmunity
A
- fewer lymphocytes undergo apoptosis
- more lymphocytes w dysfunctional antigen recognition
- Increases probability of lymphocyte attacking bodys own cells
2
Q
how do t cells form clones
A
- pathogens invade body + are engulfed by phagocyte
-APCs presents pathogen’s antigens on cell surface membrane. - receptors on specific T cells bind to antigens on APCs (clonal selection)
- T cells undergo mitosis to form clones (clonal expansion)
3
Q
cellular immune response
A
t cells + phagocytosis
4
Q
humoral response
A
b cells + antibodies
5
Q
ELISA test
A
- bind antigens to the surface of a dish + add sample
- if sample contains complementary antibodies, it will bind to fixed antigens
-wash off blood sample - secondary antibody w attached enzyme is applied + will bind to any antibody that is bound to the plate.
- wash off solution to rmove any unbound
- substrate is added which will change colour if the enzyme is present.
6
Q
why is cellular>humoral for defence against viruses
A
- virus invade host cells
- so remain hidden from antbodies within the host cell
- however after phagocytosis virus antigen presented to t cell
- by APC
7
Q
primary vs secondary immune response
A
primary = upon vaccination
- slower bc of cloning/production of antibodies
secondary = upon infection
- faster bc of memory cells
8
Q
Why does herd immunity work
A
- sufficient amount of the population is vaccinated
- harder for virus to spread
- highly unlikely people who are unvaccinated will come into contact w person who has disease
- unvaccinated people are protected
9
Q
how does HIV work
A
- particle enters bloodstream
- attachment proteins on cell surface of HIV bind to receptors on t-cell
- this enables the capsid to fuse with the cell surface membrane of the host cell, allowing the enzymes and viral RNA to enter the cell
- reverse transcriptase converts viral RNA into DNA
- DNA forms mRNA which leaves the nucleus + is translated into HIV proteins which then break away from the t-cell
- new lipid capsule reforms
