Ch.15 adaptive immune system Flashcards
how is adaptive immunity developed?
by exposure to foreign antigens or by vaccination
is adaptive immunity broad or specific?
highly specific
what components does adaptive immunity include?
cells of mononuclear phagocyte system (macrophages and dendritic cells) and cytokines
why are memory cells important to adaptive immunity?
produce strong immune responses upon re-exposure to pathogens
vaccination relies on the abilities of which cells?
memory cells
what happens if a person only has adaptive immunity?
the adaptive immunity has no chance to be informed of infection, so microbes grow out of control
what happens if a person only has innate immunity?
the innate immunity initially helps control the microbial population, but without the intercession of the adaptive immune system, the population will eventually rise
cell-mediated immunity
response toward intracellular pathogens
intracellular pathogens
microbes that have breached the cell membrane and are already inside the cell
example of intracellular pathogen
viruses
humoral immunity
attack against extracellular pathogens
extracellular pathogens
microbes that are free in the tissues, organs, or bloodstream
steps of adaptive immunity
- dendritic cells find invaders and present them to naive helper T cells and naive cytotoxic T cells
- naive helper T cells and naive cytotoxic T cells become activated
- cytotoxic T cells differentiate into active cytotoxic T cells
- helper T cells deliver cytokines to activate macrophages to increase killing power and become more phagocytic, and activate naive B cells to begin the humoral immune response
- naive B cells differentiate into plasma cells which produce antibodies to bind to free-floating antigens (extracellular pathogens)
what are the 3 steps involved in adaptive immunity?
- activation of B and T cells
- proliferation and differentiation of B and T cells
- effector action (action that takes place to elimination infection) and consequence
adaptive immunity involves activity of what type of cell?
lymphocytes
what are the 2 main types of lymphocytes?
B lymphocytes (B cells) and T lymphocytes (T cells)
where do B cells mature?
bone marrow
Where do T cells mature?
thymus
what are the 2 types of adaptive immune responses?
- cell-mediated immune responses
- antibody immune responses
primary lymphoid organs
- bone marrow
- thymus
secondary lymphoid organs
- lymph nodes
- spleen
- tonsils
- MALT
- SALT
what does MALT stand for?
mucosa-associated lymphoid tissue
what does SALT stand for?
skin-associated lymphoid tissue
secondary lymphoid organs are the only place where what can occur?
where adaptive immune responses can be initiated
where do lymphocytes gather to contact antigens?
secondary lymphoid organs
where do hematopoietic stem cells reside and what do they give rise to?
bone marrow; all blood cells including lymphocytes
where are mature lymphocytes formed?
bone marrow
once B and T cells are mature, where do they gather to wait to encounter an antigen?
secondary lymphoid organs
peyer’s patches
tissues in intestinal wall that inspect samples on intestinal content
peyer’s patches are part of what secondary lymphoid organ?
MALT
MALT plays a crucial role in ____________, preventing _____________
mucosal immunity; preventing microbial invasion by mucous membranes
M cells
specialized intestinal epithelial cells that transfer material from intestinal lumen to peyer’s patches
antigens
molecules that the body recognizes as foreign and worthy of attack
how are antigens recognized?
by 3D epitopes on antigens
epitopes
certain regions of an antigen molecule that stimulate immune responses
what are the 2 classes on MHC proteins?
MHC class 1 and MHC class 2
MHC class 1
present on all cells except RBCs
MHC class 2
- present on antigen-presenting cells (APCs)
- include B cells, macrophages, and dendritic cells
what does MHC stand for?
major histocompatibility complex
cytotoxic T cells and helper T cells have numerous copies of what?
a surface molecule called T cell receptor
what is the relationship between MHC and antigen-presenting cells?
antigens bind in the antigen-binding groove of MHC molecules
cytotoxic T cells
destroy host cells that contain viruses
helper T cells
direct and assist various responses of humoral and cell-mediated immunity
T cell receptor
binds to specific antigens presented by dendritic cells or antigen-presenting cells
will T cell receptors bind to free floating antigens? why or why not?
no because it is a part of cell-mediated immunity, which is about attacking an intracellular pathogen)
are T cells part of cell-mediated or humoral immunity?
cell-mediated
T cell activation steps
- recognition of presented antigen
- stimulatory signals secreted from APC
APC
antigen-presenting cell
how are cytotoxic T cells and helper T cells different physically?
they have different CD markers
once infected, what do cytotoxic T lymphocytes do in cell-mediated immunity?
- tells infected “self” cells to go through apoptosis
- some cells with become memory CTLs and remain in secondary lymphoid organs in case the antigen presents again
once infected, what do T helper cells do in cell-mediated immunity?
- produce cytokines that activate B cells and macrophages
- some cells become memory T helper cells that will remember those specific antigens
T regulator cells
suppress immune activation from overreacting and responding to harmless substances
function of B cells in humoral immunity
have numerous copies of a B cell receptor on their cytoplasmic membrane and are activated and divide upon antigen recognition
B cells include:
plasma cells and memory cells
plasma cells
activated B cells that produce antibodies
B cell receptor
membrane-bound version of antibody (free floating antigen) that the B cell is genetically programmed to make
what happens when a naive B cell encounters an antigen that its B cell receptor can combine with?
an interaction signals the B cell to respond
what must occur for a B cell to be activated?
- B cell encounters an antigen that its B cell receptor can bind to
- T helper cell gives a 2nd signal that the antigen should be eliminated
what occurs once a B cell is activated?
the B cell proliferates and differentiates into plasma cells (which produce antibodies) and memory cells (which respond quickly upon re-exposure of the same antigen)
steps for clonal selection and expansion of lymphocytes
- immature lymphocytes in bone marrow
- naive lymphocytes form when immature lymphocytes matures and is moved to secondary lymphoid organ
- activated lymphocytes occurs when the cell comes into contact with the epitope it is programmed to respond to
- effector lymphocytes/memory lymphocytes