Immunology 1 Flashcards
what are the 2 major functional divisions in immune system?
innate immunity and adaptive immunity
what is the “1st line of defense”
innate immunity
which immune system is less specific - each cell or molecule recognizes a range of targets
innate immunity
which immune system is genetically “hard-wired” - cells and molecular effectors don’t change during the lifespan of the organism
innate immunity
what immune system is activated when innate defenses are breached?
adaptive immunity
which immune system is highly specific - each cell or molecule recognizes a particular target
adaptive immunity
which immune system is genetically “changeable” - cells and molecular effectors change their germline DNA to produce unique receptors/effectors during the lifespan of the organism
adaptive immunity
What is an antigen?
a substance that can bind to a receptor of the adaptive immune system
what are the B-cell receptors that can be released from a B cell into the ECF called?
antibody
what is an immunogen?
a substance that can generate an adaptive immune response
what is an epitope?
the part of the antigen molecule where the antibody attaches to
what is a hapten?
a substance that can bind to an antibody, but CANNOT generate an immune response
what is a lymphocyte receptor repertoire?
the set of antigen receptors in a given individual’s immune system
Explain the clonal selection theory
in a pre-existing group of lymphocytes (both B and T cells), a specific antigen activates only its counter-specific cell, which then induces that particular cell to multiply, producing identical clones for antibody production
what does immature mean?
a cell that has not reached a point where it can become activated - usually refers to cells of the adaptive immune system
what does naive mean?
a mature cell that has not yet been activated - always refer to the adaptive immune system
what does activated or effector mean?
a cell (or a group of cells) that is currently an active participant in an immune response
what does anergic mean?
a cell that responds to receptor binding by deactivation of the cell - it “goes to sleep”
what does clone mean?
a group of effector T or B cells that express the same antigen receptor and are derived from the same parent cell
Naive B cells express antibodies on their surface, where they are called…
B cell receptors
B Cell receptors have …
2 light chains and 2 heavy chains, each with variable and constant regions
what region of the b cell receptors that are “shuffled” and that can bind to anitgen?
variable region
most antibodies bind to what?
protein antigens
recognized amino acid sequence can be either…
continuous and discontinuous
T cell receptor consist of?
2 chains 1 alpha, 1 beta, each with variable region and a constant region
important to note that T-cell receptor is never secreted - it is,,,
always stays attached to the membrane
what is antigen presentation?
T receptors only recognize antigen by close communication with molecules on other cells
explain about the memory of the adaptive immune system
exposure to an antigen increases its ability to respond to the same or closely related antigen following re-exposure
secondary immune responses are generally:
- faster
- larger
- qualitatively different and often relatively high-affinity B-cell receptors
immune responses to self can result in
autoimmunity
what are monocytes?
a type of myeloid progenitor cell that circulate in the blood and differentiate into macrophages upon migration into tissue
what are the mature form of monocytes?
macrophages
T or F: macrophages present antigens to T cells
True
where are dendritic cells found?
body’s tissues
what does dendritic cells do?
during infection, recognizes infection and transports antigen to lymphoid organs
what are the different granulocytes?
- neutrophils
- basophils
- eosinophils
- mast cells
what are the different types of myeloid cells?
- Granulocytes
- Monocytes
- Dendritic cells
what are neutrophils?
phagocytic and enter sites of infection and dies in infected tissues and form pus (purulent inflammation)
- most numerous cellular component of innate immune system
what are eosinophils
defense against parasites and involved in hypersensitivity responses
what are basophils
along with mast cells, protect mucosal body surfaces and release histamine in hypersensitivity responses
what are mast cells?
reside in all connective tissues - only resident granulocyte and have an unique role
what are the different lymphoid progenitor cells?
- B cells
- T cells
- NK cells
where are B cells derived?
bone marrow
upon activation, B cells differentiate into…
antibody-secreting plasma cells
where are T cells derived?
thymus
T cells become either…
helper T cells (Th)
Cytotoxic T lymphocytes (CTL)
What do helper T cells do?
activate other cells
what do cytotoxic T cells do?
kill cells that express foreign molecules
what do NK cells do?
important in the innate immune system, they lack antigen-specific receptors and they kill infected and altered cells
what are the 2 types of lymphoid tissues?
- primary (central) lymphoid organs
- secondary (peripheral) lymphoid organs
what happens at the primary lymphoid organs?
where lymphocytes are generated and mature
what do primary lymphoid organs include?
bone marrow and thymus
where do B cells mature?
bone marrow
where do T cells mature?
thymus
what happens at the secondary lymphoid organs?
where adaptive immune responses are initiated (where antigens and B/T cell receptors encounter each other)
what do secondary lymphoid organs include?
lymph nodes, spleen, and MALT
where are lymph nodes located?
lie at junctions of lymphatic vessels
what do lymph nodes do?
collect extracellular fluid (lymph) and return it tot he blood (via lymphatics)
what are afferent lymphatics?
drain lymph and antigens from tissues, carrying it to the nodes where antigen is trapped
what does the spleen do
“filter for blood” - collects blood-borne antigens and also destroys aged RBCs
spleen is divided into 2 parts, which are…?
red pulp and white pulp
what is red pulp
where old RBCs are destroyed
what is white pulp
where lymphocytes surround arterioles entering organ
white pulp is further subdivided into what?
corona and periarteriolar lymphoid sheath
what is the purpose of MALT?
to collect antigens from mucosal surfaces
GALT includes…
tonsils, adenoids, appendix, and Peyer’s Patches (PP)
what does peyer’s patches do?
collect antigens from epithelial surfaces of GI tract via M cells
