(exam 3) ch 17 adaptive immunity: specific defenses of the host Flashcards
________ immunity is defenses against any pathogen; rapid and fast and is present at birth.
innate immunity
________ immunity is resistance to a specific pathogen; it is slower to response and has a memory component to it.
adaptive immunity
what are two ways that adaptive immunity can be acquired?
1) infection or 2) vaccination
what is the primary response of the adaptive immune system?
first time the immune system combats a particular foreign substance
what is the secondary response of the adaptive immune system?
“the reencounter”- later infections with the same foreign substance; the immune response is faster and more effective due to the memory component
the adaptive immune system has a dual nature. what are the two components of this system?
1) Humoral immunity
2) Cellular immunity
________ immunity is the component of the adaptive immune system that fights invaders and threats outside cells; takes place in extracellular fluid; defense against bacteria, toxins, & viruses BEFORE they enter the host
humoral immunity ** home = protects the home (i.e cells)**
the humoral immune system is performed by protective molecules termed __________.
Antibodies = immunoglobulins (Ig)
antibodies recognize and combat foreign molecules called _______.
antigens
what type of cells are part of the humoral immunity (of the adaptive immune system)?
B cells (B lymphocytes)
______ are lymphocytes with antibodies to specific antigens on their surface.
B lymphocytes
Binding of surface antibodies to antigens activates B cells to do what?
secrete more antibodies against that particular antigen
_________ immunity is the component of the adaptive immune system that focuses on antigens that have already entered cells.
Cellular immunity (cell mediated immunity)
what type of cells are part of cell-mediated immunity (of the adaptive immune system)?
T cells (T lymphocytes)
______ are cells that recognize antigenic peptides processed by phagocytic cells.
T lymphocytes
__________ are on the T cell surface contact antigens that cause T cells to 1) destroy antigen presenting cell or 2) secrete cytokines instead of antibodies
T cell receptors (TCRs)
where do both B and T cells originate from?
from stem cells in red bone marrow
where do B cells mature?
mature in red bone marrow
where do T cells mature?
mature in the thymus
_______ are chemical messengers produced in response to a stimulus and are produced by most immune cells.
Cytokines
what are interleukins (ILs)?
type of cytokines; communication between leukocytes
what are chemokines?
type of cytokines; cause of migration of leukocytes (chemotaxis)
what are interferons (IFNs)?
type of cytokines; interfere with viral infections
what are tumor necrosis factor alpha (TNF-a)?
type of cytokines; cause inflammation
what is a cytokine storm?
overproduction of cytokines resulting in tissue damage
______ are substances that cause the production of antibodies and are usually components of invading microbes or foreign substances.
antigens
______ are specific regions on antigens where antibodies will bind.
Epitopes
_______ are antigens that are too small to provoke immune responses; they require attachment to a carrier molecule in order for the immune system to recognize it
Haptens
once the immune system recognizes the Haptens, what happens to the carrier molecule?
it is no longer needed
_______ is the number of antigen-binding sites on antibodies.
valence
if an antibody is bivalent, what does this mean?
the antibody has two binding sites
the structure of antibodies is a four protein chains to form a Y-shape. What are the chains made up of?
two identical light chains and two identical heavy chains
how are the chains in antibodies connected?
joined by disulfide links
_________ are at the ends of arms and bind to epitopes?
variable (v) regions
_________ is the stem which is identical for particular Ig classes.
constant (Fc) region
what are five classes of antibodies?
IgG, IgM, IgA, IgD, & IgE
which class of antibodies is one of the most used?
IgG
_______ has 80% of serum antibodies and is located in blood, lymph, and intestine; it passes through blood vessels into tissues.
IgG
______ is made of 5 monomers and is very big; has 6% of blood serum antibodies; and is first response to infection which is very fast and short lived
IgM
______ is 13% of blood serum antibodies and **prevents microbial attachment to mucous membranes. **
IgA
__________ is genes that encode molecules on the surface of cells (that can be recognized by immune cells)
Major histocompatibility complex (MHC)
where are class 1 MHCs located? what is the purpose of this gene?
on the membranes of all nucleated animal cells; critical in order to identify “ self” from non self (foreign antigens)
where are class 2 MHCs located?
on the surface of antigen-presenting cells (APCs)
what are some examples of antigen presenting cells?
B cells, dendritic cells, or activated macrophages
five steps of activation and clonal expansion:
1) inactive _______ contain surface Ig that bind to antigens
2) ______ internalized and processes the antigen
3) antigen fragments are displayed on MHC class _____ molecules
4) _______ contacts the displayed antigen fragment and releases cytokines that activate B cells
5) _______ undergoes proliferation (clonal expansion)
1) B cells
2) B cells
3) MHC class two
4) T helper cells (Th)
5) B cell
clonal selection differentiates activated B cells into what two things?
1) antibody-producing plasma cells
2) Memory cells
what are antibody-producing plasma cells ?
plasma cells that make antibodies and then secrete them into circulation
what are the two methods of B cell activation?
1) T-dependent antigen
2) T-independent antigen
what is T-dependent antigen activation of B cells?
antigen that REQUIRES a T helper cell in order to produce antibodies (resulting in a better immune response and memory)
what is T-independent antigen activation of B cells?
stimulates B cells WITHOUT the help of T cells (usually molecules with repeating subunits) provoke a weak immune response and no memory cells are generated
__________ complex forms when antibodies bind to antigens
antigen-antibody complex
the closer the physical fit between the antigen-antibody complex, the strong the bond is which is called ?
affinity
if the antigen-antibody complex has a high affinity that means ?
they have a strong bond
if the antigen-antibody complex has a low affinity that means ?
they have a weak bond
Antibodies alone do not damage antigens and pathogens; they protect the host by doing what?
by tagging foreign molecules or cells for destruction
what is angulation?
antibodies cause antigens to clump together which reduces the number of infectious units to deal with
what is opsonization?
coating antigen with antibodies which enhances phagocytosis of pathogen
what is antibody-dependent-cell-mediated cytotoxicity?
similar to opsonization but the target cell is too large to be phagocytksed so the antibodies attach to target cell cause destruction by macrophages, eosinophils, and NK cells
what is neutralization?
antibody binds to antigen and blocks microbes and toxins from attaching to host cells
what is activation of the complement system?
bound antibodies causes cytolysis, inflammation and opsonization to pathogen
___________ are B cells/ dendritic cells/ or activated macrophages that use class 2 MHC on surface to present antigens to T cells.
Antigen-presenting cells (APCs)
__________ have long extensions, engulf and degrade microbes to display them to T cells.
Dendritic cells (DCs)
__________ are activated by cytokines or the ingestion of antigenic material; they migrate to the lymph tissues, presenting antigens to T cells
macrophages
______________ are surface glycoproteins that are important for receptor binding.
Clusters of differentiation (CD)
CD4+ T -cells are also known as ?
T helper cells (Th)
what class MHC do CD4+ T cells bind to?
bind to class two molecules
CD8+ T -cells are also known as ?
cytotoxic T lymphocytes (CTL)
what do CD4+ T-cells do?
help with cytokine signaling with B-cells; interact directly with antigens
what class MHC do CD8+ T cells bind to?
bind to MHC class 1 molecules
what do CD8+ T-cells do?
CTLs recognize and kill self-cells altered by infection; they also release perforin (pore forming protein) which can induce apoptosis (programmed cell death)
what are naive T cells?
T cells that have not encountered a pathogen
what are two types of nonspecific cells?
1) Natural Killer (NK) cells
2) Antibody-dependent cell-mediated cytotoxicity
___________ are granular leukocytes that destroy cells that DON’T express MHC class one self-antigens; they form pores in the target cell leading to lysis or aptosis
natural killer (NK) cells
__________ secretes chemicals to lyse the target cell because pathogens such as protozoans and helminths are too large to be phagocytized. It makes them a target cell by coating them with antibodies.
Antibody-dependent cell-mediated cytoxicity
what is a secondary (memory) immune response?
occurs after the second exposure to an antigen
what is different about a secondary immune response compared to the first?
it is a rapid response, lasts many days, and is greater in magnitude; the memory cells produced in the first immune response are activated by secondary exposure
what is antibody titer?
direct way to measure the relative amount of antibody serum and reflects the intensity of humoral response
immunity that is acquired from an infection is what type of immunity?
naturally acquired active immunity
immunity acquired transplacental or via breast milk (usually young children / newborns) is what type of immunity?
naturally acquired passive immunity
immunity acquired from a vaccine (immunization) is what type of immunity?
artificially acquired active immunity
immunity acquired from an injection of antibodies is what type of immunity?
artificially acquired passive immunity
