CPA #18 Questions Flashcards
what are the 5 attributes of adaptive immunity?
- specificity
- inducibility
- clonality
- unresponsiveness to self
- memory
define: specificity
a particular immune response only acts against a specific antigen
define: inducibility
specific antigen-containing pathogen activates cells of adaptive immunity
define: clonality
once activated, the cells of adaptive immunity are generated to created multiple generations of clone cells
define: unresponsiveness to self
adaptive immunity does not work against normal body cells
define: memory
immunological memory for specific pathogens
what is the lymphatic system?
composed of lymphatic vessels, lymph, lymphoid cells, tissues, organs; directly involved in adaptive immunity
what is the purpose of the lymphatic system?
acts as surveillance system that screens tissues of body for foreign particles
what are the primary lymphoid organs?
bone marrow, thymus
what are the secondary lymphoid organs?
lymphatic vessels, lymph nodes, tonsils, lymphoid tissue
what are lymphatic vessels?
form one-way system taking lymph from local tissues and returning to the circulatory system.
where does lymph come from?
fluid that has leaked out of blood vessels into surrounding tissues
how does lymph flow through body?
one way flow
where does lymph drain to?
heart
where are lymph nodes concentrated?
neck, groin, armpits, and abdomen
what cells are found in lymph nodes
WBC (B and T lymphocytes)
what is the function of lymph nodes?
sites to facilitate interactions among immune cells and between immune cells and material that arrives at lymph nodes
what is the major function of the spleen?
filters blood; removes bacteria, viruses, toxins, and other foreign matter from blood; stores platelets and blood components
what is the major function of the tonsils?
physically trap foreign particles that enter mouth or nose
what does MALT stand for?
mucosa-associated lymphoid tissue
what tissues are a part of MALT?
appendix, respiratory tract, vagina, urinary bladder, mammary glands; contains most of the bodies lymphocytes
what does MHC stand for?
major histocompatibility complex; cluster of genes that code for specific proteins
how were MHC discovered?
attempted grafting skin from one animal to another in attempt to treat burn victims; if the animals were not closely related, the recipient would reject the graft
what are the 2 classes of MHCs?
- class I MHC proteins
- class II MHC proteins
what do MHCs bind to?
antigens
define: class I MHC
found on cytoplasmic membrane of all human cells (except RBCs)
define: class II MHC
found on special cells called antigen-presenting cells (APC)
define: APCs
antigen-presenting cells; regularly present antigens; include macrophages, B cells, and dendritic cells
why do some foreign epitopes may not trigger immune response?
MHC binding diversity is dependent on the individuals genes ; some epitopes won’t be bound to the MHC, therefore there is no immune response (ex. peanut allergy)
how is phagocytosis used by APCs?
phagocytose microbe, gets antigen attached to MHC, essentially stealing it to match it to any other cells
what immune response are T cells involved in?
cell-mediated immune responses
what types of pathogens do T cells fight against?
cancer, viral infections
where are T cells made?
red bone marrow
where do T cells mature?
thymus
what percentage of lymphocytes are T cells?
70-85%
what does TCR stand for?
T cell receptor
where are TCRs located?
cytoplasmic membrane of T Cells
how many different TCR’s are there?
10,000,000,000
why are TCR’s both specific and random?
every T cell randomly created & specific to antigen
what are the 3 types of T cells?
- cytotoxic T cells (Tc cells; CD8 cells)
- helper T cells (Th cells; CD4 cells)
- regulatory T cells (Tr cells; suppressor cells)
define: th1 cells
type 1 helper cells; assist cytotoxic T cells and stimulate and regulate innate immunity
define: Th2 cells
function in conjunction with B cells
what do helper T cells secrete?
cytokines that regulate the entire immune system
define: suppressor T cells
suppress immune responses and promote tolerance of certain antigens
what happens when the immune system is not tolerant of “self”?
autoimmune disease
What is the major function of B cells?
secrete soluble antibodies
what does BCR stand for?
B cell receptor
where are BCRs found?
surface of B lymphocytes
how many different types of BCRs are there?
500,000
why are BCRs specific and random?
many BCRs will recognize any antigen, but each BCR recognizes only one epitope of the antigen
what stimulates B cells?
antigenic epitope
what happens when a B cell is stimulated?
cell division, leading to identical offspring that secrete immunoglobulin into blood/lymph
define: plasma cells
activated immunoglobulin-secreting B lymphocytes
how are antibodies similar and different to BCRs?
similar shape, but antibodies lack transmembrane portions
where do B cells undergo clonal deletion?
red bone marrow
how are self-reactive B cells different than self-reactive T cells?
self-reactive B cells: may become inactive or change BCR
self-reactive T cells: undergo apoptosis
how do B and T cells communicate?
chemical signals (cytokines)
define: immunological synapse
Tc cell binds to the dendritic cell to form a cell-cell contact site
define: clonal expansion
activated Tc cells reproduce to form memory T cells and more Tc progeny
define: self-stimulation
Tc cells no longer require either an APC or a helper T cell
define: memory T cells
some activated T cells; state of “suspended animation” in lymphoid tissues
define: memory response
an enhanced cell-mediated immune response upon subsequent exposure to the same antigen
define: T-dependent antibody immunity
antibody immune response depend on interaction with helper T cells
define: plasma cells (B cells)
most differentiated B cells; secrete antibodies with binding sites identical to one another and complementary to specific antigen
define: memory B cells
do not secrete antibodies; retain BCRs and persist in lymphoid tissues
define: primary immune response
small amounts of antibodies are produced and may take days before enough antibodies are made to completely eliminate the toxins; create memory cells
define: secondary immune response
many memory cells recognize and respond to antigen much quicker/faster to eliminate toxin
what are the 4 types of acquired immunity
- naturally acquired active immunity
- naturally acquired passive immunity
- artificially acquired active immunity
- artificially acquired passive immunity
define: naturally acquired active immunity
body responds to exposure to pathogens and environmental antigens via immune responses
ex. chicken pox
define: naturally acquired passive immunity
passively pass to unborn child via placenta or newborn child via breastfeeding
define: artificially acquired active immunity
vaccine/ immunizations; induce immunity via antigens
define: artificially acquired passive immunity
antibodies for antisera/antitoxins created from immune humans or animals (typically horses)
