Lecture 15 - Adaptive Immunity Flashcards
what line of defense is adaptive immunity?
third line of defense
when does adaptive immunity develop?
adaptive immunity develops during our life as an adaptation to infection with an indaver
what does it mean when adaptive immunity is delayed?
adaptive immunity is delayed, meaning the responses follow innate immunity by several days (7-14 days)
are the responses of adaptive immunity specific or non-specific?
responses of adaptive immunity are specific to a foreign invader, so its specific to each pathogen
does adaptive immunity have memory or non-memory?
adaptive immunity makes memory to prevent reinfection by the same invader, so this response is more powerful if it happens again
what are the 5 hallmarks of adaptive immunity?
-Third line defense
-Adaptation
-Delayed
-Specific
-Memory
where are antigens (Ag) located?
they are located on invaders
what are Antigens often made out of?
Ag’s are often proteins or polysaccharides
how is the adaptive immune system specific to antigens?
the immune cells recognize the antigens on invaders using specific binding (aka they identify specific molecules on the pathogen)
antigens are located on the pathogens, and ____ defense recognizes it
3rd line defense recognizes it
what is an example of an antigen from our labs?
H-antigen in E. coli 0157 H:7
how do antigens respond when immune cells recognize them?
they respond by producing antibodies, killer cells, and activated macrophages to destroy invaders
where does the name of the antigen come from?
antibody-generators
what are the two categories of lymphoid organs?
primary and secondary
what do primary lymphoid organs consist of?
bone marrow and thymus
what generates and matures in primary lymphoid organs?
lymphocytes (B cells and T cells; b for bone marrow and t for thymus)
what do secondary lymphoid organs consist of?
lymph nodes, tonsils, spleen, SALT, and MALT
what happens in the site of secondary lymphoid organs? what is an example?
this is where antigens are brought together with lymphocytes.
example: lymph carrying excess tissue fluids brings antigens to lymph nodes that contain lymphocytes.
what are the two components of adaptive immunity?
- Humoral: antibody-mediated immunity (makes antibodies)
- Cellular: cell-mediated immunity (makes killer cells)
what does humor mean in humoral immunity?
fluids (blood, tissue fluids)
what is humoral immunity against?
it is against extracellular antigens; outside of the cell. example: circulating bacteria or toxins, foreign RBCs
what is humoral immunity mediated by?
B lymphocytes (cells)
where do B cells develop and mature in humoral immunity? what do they gain (what receptors)?
B cells develop and mature in bone marrow, where they gain specific B cell receptors (BCRs)
where do B cells travel to after they gain their receptors? what are they called here?
They travel to secondary lymphoid organs to “lie in wait” or circulate, they are called naive B cells
why are they called naive B cells?
because they are not yet activated
each B cell is specific to what?
each B cell is specific to each antigen
what is cellular immunity against?
cellular immunity is against intracellular antigens; inside the cell. (example: viral-infected cells, cancer cells, and transplanted tissue)
what is cellular immunity mediated by?
T lymphocytes (cells) and macrophages
where do T cells develop and mature? what do they gain (what receptors)?
T cells develop in bone marrow and mature in the thymus. This is where they gain specific T cell receptors (TCRs)
where do the T cells travel after gaining TCR’s in cellular immunity?
they travel to secondary lymphoid organs to “line in wait” or circulate called naive T cells
what are two T cell types?
-Cytotoxic T cell (CD8+)
-Helper T cell (CD4+)
in cytotoxic T cells, what does the TCR bind to?
TCR binds to Ag-MHC 1 complex
what doe MHC stand for?
major histocompatibility complex
what do cytotoxic T cells do?
all the cells breakdown internal antigens and display them on MHC 1
what does the helper T cell bind to?
the TCR binds to Ag-MHC 2 complex
in helper T cells, what breakdown the foreign Ags and display them on the MHC 2?
Antigen presenting cells (APCs) breakdown foreign Ags and display them on MHC 2
we develop B cells and T cells specific (via receptors) to what?
we develop B cells and T cells specific (via receptors) to an enormous diversity of possible antigens (>1 billion). example: measles virus
what do naive B cells scout for?
Naive B cells scout for extracellular antigens (example: measles in blood and bodily fluids)
what do naive T cells scout for?
Native T cells scout for intracellular antigens (example: measles in cells)
how do naive B and T cells get activated?
if naive B and T cells come across the matching antigen, they get activated
what happens after naive B and T cells get activated?
they reproduce and differentiate to form:
-effector cells
-memory cells
what do effector cells do?
they destroy the invader (it takes action)
what do memory cells do?
they are saved for the next exposure to the same invader; so that they can mount a quick and intense secondary response