6/22 - Diseases of Immune System Flashcards
what is vital for survival
immune system
what are 2 broad categories of mechanisms of defense against microbes
- innate immunity
- adaptive immunity
what are the classes of innate immunity
- epithelial barriers
- dendritic cells
- phagocytes
- NK cells
- complement cells
how many hours does it take for innate immunity to take place
6-12 hours
what cells are part of adaptive immunity
B and T lymphocytes
what immunity is always present, ready to provide defense against microbes and to eliminate damaged cells?
innate immunity
what component of innate immunity blocks entry of microbes
epithelial barriers
what component of innate immunity are mainly neutrophils and macrophages
phagocytic cells
what component of innate immunity is a phagocytic cell w/ dendrites
dendritic cells
in blood stream = ___
out of blood stream, in tissue = ___
monocytes; macrophages
NK cells are a type of what
type of lymphocytes
cells that participate in innate immunity can recognize ___ that are shared among related microbes and are often essential for infectivity
certain microbial components
what pattern recognition receptors recognize molecules
- plasma membrane receptors
- endosomal receptors
- cytosolic receptors
what receptors detect extracellular microbes
plasma membrane receptors
what receptors detect ingested microbes
endosomal receptors
what receptors detect microbes in the cytoplasm
cytosolic receptors
what are the classes of receptors in innate immunity
- toll-like receptors
- NOD-like receptors
- inflammasomes
what is the best known pattern recognition receptors
toll-like receptors
what receptors recognizes a different set of microbe molecule and is present on plasma membrane and endosomal vesicles?
toll-like receptors
NOD-like receptors are a type of what kind of pattern recognition receptors
cytosolic receptors
what receptors recognizes a wide variety of substances including products of necrotic cells (uric acid, released ATP disturbances (loss of K+), and some microbial products)
NOD-like receptors
what receptor activates caspase-1
inflammasome
inflammasomes activate ___ to generate ___
caspase-1 (caspase-1 cleaves a precursor form of cytokine IL-1) to generate active IL-1
activated ___ is a mediator if inflammation, and recruits ___ and induces ___
IL-1, leukocytes; fever
innate immune system provides host defense by what 2 main reactions
- inflammation
- provides signals that stimulate the subsequent more powerful adaptive immune response
B!
what is primary cell of defense in acute inflamation? chronic inflammation?
acute = neutrophils
chronic = lymphocytes
what immunity consists of lymphocytes and their products, including antibodies
adaptive immunity
what are the two types of adaptive immunity
- humoral immunity
- cell-mediated or cellular immunity
what immunity protects against extracellular microbes and their toxins
humoral immunity
“doesn’t fight physically -> spits and runs away”
what type of immunity is responsible for defense against intracellular microbes
cell-mediated or cellular immunity
“takes inside and kills microbe”
humoral immunity is mediated by what?
B (bone-marrow) lymphocytes AND their secreted products (antibodies)
antibodies are also called what
immunoglobulins
cellular immunity is mediated by what?
T (thymus-derived) lymphocytes (doesn’t produce product and is activated by receptors on cell)
do lymphocytes express highly specific receptors for a wide variety of substances (antigens)?
YES
T/F: lymphocytes and other cells of immune response are fixed in a particular tissue
FALSE! NOT fixed
where do lymphocytes constantly circulate?
lymphoid and other tissues via blood and lymphatic circulation
the constant circulation of lymphocytes promotes what?
immune surveillance
are different classes of lymphocytes anatomically segregated in lymphoid organs? do they ever interact?
YES - anatomically segregated!
only interact when stimulated
what are the types of lymphocytes
- naive lymphocytes
- effector lymphocytes
- memory lymphocytes
what are mature lymphocytes that have not encountered an antigen for which they are specific
naive lymphocytes
what are activated lymphocytes, after recognition of an antigen they eliminate microbes
effector lymphocytes (takes a couple of days)
what are lymphocytes with a heightened level of awareness; react rapidly and strongly to combat microbes in case of reinfection
memory lymphocytes (doesn’t wait a couple of hours)
T lymphocytes develop in ___ from ___ cells
thymus from hematopoietic stem cells
mature T cells are found in where?
blood and T-cell zones of peripheral lymphoid organs
what percent of blood is lymphocytes
60%-70%
!
in the blood, are there more B or T cells?
T-cells
each T-cell recognizes a specific cell-bound antigen thru what?
thru an antigen-specific TCR
what are the 3 major populations of T cells
- helper T lymphocytes
- cytotoxic T lymphocytes (CTL)
- regulatory T lyphocytes
what stimulates B lymphocytes to make antibodies and activate other leukocytes to destroy microbes?
helper T lymphocytes
what lymphocytes kill infected cells w/ antigen presenting cells
cytotoxic T lyphocytes (CTL)
what lymphocytes limit immune response and prevent reaction against self antigens
regulatory T-lymphocytes
what T cells are most common? less common?
most common: CD4+ (60% mature T)
less common: CD8+ (30% mature T)
what T cells produce cytokines and assist macrophages and B cells
CD4+
since CD4+ produce CYTOKINES, what type of T cells are produced?
helper T cells
CD4+ bind to what MHC displayed on antigens?
class II MHC
what T-cell functions as cytotoxic cells to destroy host cells harboring microbes?
CD8+
CD8+ binds to what MHC molecules that are displayed on?
class I MHC
what produces antibody molecules, the mediators of humoral immunity?
B lymphocytes
b lymphocytes develop from precursors from where
bone marrow
B-lymphocytes are ___% of circulating lymphocytes
10-20%
B lyphocytes are present where?
- circulating lymphoid tissue (bone marrow)
- peripheral lymphoid tissue (e.g. lymph nodes, spleen, tonsils)
what are the steps of immune response
- antigen RECOGNITION
- ACTIVATION of specific lymphocytes to proliferate and differentiate to effector and memory cells
- ELIMINATION of antigens
- DECLINE of response
- MEMORY cells being long-lived survivors
what cells destroy irreversibly stressed and abnormal cells without prior exposure?
natural killer cells
kill: viral-infected cells, tumor cells
NK cells make up ___% of peripheral blood lymphocytes
5-10%
what cells are Lyse IgG coated target cells?
NK cells (antibody dependent cell mediated toxicity)
T/F: NK cells secrete cytokines which activate macrophages
TRUE
