Adaptive Immunity Flashcards
____ is specific, systemic, and has memory
adaptive immunity
The two major cells of adaptive immunity are:
T and B cells
The three types of T cells:
cytotoxic, regulatory, helper
The two types of B cells:
plasma and memory
B cell receptors ___ bind directly to antigens
can
T cell receptors ___ bind directly to an antigen alone
cannot
T cells require a ___ in order to bind
APC
Class 1 MHC proteins are found on what cells?
all cells except RBC
Class 2 MHC proteins are found on what cells?
macrophages, B cells, and dendritic cells
CD_ proteins can bind with Class 1 MHC proteins
CD8
CD_ proteins can bind to Class 2 MHC proteins
CD4
What cells have CD8?
cytotoxic T cells
What cells have CD4?
helper and regulatory T cells
How are helper T and regulatory T cells activated?
Antigens are presented to them by APCs including macrophages, dendritic cells, and B cells
What 3 events are required for activate helper and regulatory T cells?
1- antigen presentation within a MHC protein on an APC
2- costimulus–binding of nonantigenic proteins of APC and helper/regulatory T cell
3-secretion of cytokines, IL1, and TNFalpha by APC
Once helper T cells are activated, they can then activate and stimulate what 4 cell types?
dendritic cells, mast cells, B cells, and cytotoxic T cells
Helper T cells secrete ___ which activates a CD8 cytotoxic T cell
IL-2
Viral proteins produced within an infected cell and proteins produced by oncogenes in cancer cells can act as antigens to be an APC for what cells?
cytotoxic T cells
What are the two things a cytotoxic T cell does once it recognizes an infected cell?
1-releases cytokines to attract other immune cells
2-destroys cells by either releasing perforins and granzymes or binding to Fas receptors and causing apoptosis
____ T cells remain in the body after an infection
memory cytotoxic T cells
Activated T helper cells secrete ___ and ___ which causes activation and proliferation of natural killer cells and macrophages
IL-2 and gamma interferon
____ are immunoglobulins that can attach to antigens
antibodies
What are the 5 classes of antibodies?
G, M, A, D, E
The ____ ends of antibodies are identical for all immunoglobulins within a class
constant
The ___ ends of antibodies are specific to each antigen
variable
The ___ region can bind to other things like complement proteins, phagocytes, etc.
Fc
The antibody isotype of a ___ changes during cell development and activation
B cell
Immature B cells express only the ___ isotype on the surface of the cell
IgM
Mature, naive B cells express both surface ___ and ___ isotypes, and the cell is ready to respond to antigen
IgM and IgD
When a B cell is activated by an antigen, the B cell starts to produce the antibody in a ___ form rather than a ___ form
secreted; membrane bound
Some ____ undergo isotype switching to IgE, IgA, or IgG so that each isotype can then be produced to fight a pathogen
daughter cells
___ is secreted before IgG
IgM
__ is the only antibody capable of crossing the placenta to give passive immunity to the fetus
IgG
IgG and IgM bind to ___ and ___
bacteria and viruses
___ binds to and activates basophils and mast cells, as well as binds to some bacteria
IgD
___ is secreted by B cells in GI, respiratory, and urogenital tracts and is secreted in milk, saliva, and tears.
IgA
IgA works with ___ to hydrolyze bacterial cell walls
lysozymes
__ binds to allergens and works on multicellular parasites
IgE
What are the 3 things that the Fc portion of an antibody can bind to?
1-C1 complement proteins (activates the complement pathway)
2-phagocytes (opsonization)
3-NK cells (antibody-dependent cellular cytotoxicity)
What is the relationship between C1 complement protein and antibodies?
1- antigen binds to antibody
2- C1 binds to Fc region of antibody
3- classical complement is activated
What is the relationship between antibodies and opsonization?
1-antigen binds to antibody
2-receptors on a phagocyte bind to Fc region of bound antibody
3-coats for phagocytosis
What is the relationship between NK cells and antibodies?
1-?????
____ is when antibody binds to bacterial exotoxins or viruses so that they cannot attach to cell receptors
neutralization
___ is the clumping of cells
agglutination
___ is when large insoluble complexes are formed
precipitation
What are the three processes that enhance phagocytosis?
neutralization, agglutination, and precipitation
When an antibody-antigen complex activates complement, it results in both ___ and ___
inflammation and cell lysis
What are the two main functions of regulatory T cells?
1-maintain tolerance to self-antigens (destroy peripheral T or B cells that bind to self-antigen and prevent autoimmune response)
2-suppress the immune response (think of positive feedback to prevent ongoing immune response)
Regulatory T cells release ___ and ___ which are inhibitory cytokines that act on other immune cells
interleukins and adenosine
How do regulatory T cells regulate immune response? 5
1-reduce secretion of pro-inflammatory cytokines
2-reduce expression of antigen-receptor complexes on APCs
3-adenosine causes increase in intracellular concentration of cAMP in cytotoxic and helper T cells (cAMP accumulation inhibits cell function)
4-transfer cAMP directly into Tc or Th cells via gap junctions
5-adenosine acts as an autocrine by increasing the number of regulatory T cells
____ directly kill immune cells with granzymes and perforins
regulatory T cells
Regulatory T cells also have receptors for what 2 things?
1-IL-2 (so that IL-2 can’t activate other immune cells)
2-antigen-receptor complex of APCs (so can’t present antigens)
____ is when you are actively producing antibodies after you have been infected by a pathogen
active naturally acquired immunity
___ is when you are actively producing antibodies after an antigen is intentionally introduced into the body and memory is formed (vaccines)
active artificially acquired immunity
___ is when you are NOT producing the actual antibodies but the antibodies have come from the mother–IgG through the placenta or IgA from breast milk
passive naturally acquired immunity
___ is when you are NOT producing the actual antibodies but you have received an injection of antibodies after exposure to some toxin or exotoxin, or when an Rh- mother has an Rh+ fetus
passive artificially acquired immunity
