Lecture Test 4 Part One Flashcards
what is immunology?
the study of all biological, chemical and physical events surrounding the function of the immune system
what is the first line of defense?
any barrier that blocks invasion at the portal of entry–nonspecific
what is the second line of defense?
protective cells and fluids; inflammation and phagocytosis–nonspecific
what is the third line of defense?
acquired with exposure to foreign substance; produces protective antibodies and created memory cells–specific
what are host defenses?
innate, natural defenses
adaptive immunities
what are innate, natural defenses?
present at birth, provide nonspecific resistance to infection
what are adaptive immunities?
specific, must be acquired
what are the four major subdivisions of the immune system?
reticuloendothelial system (RES)
Extracellular fluid (ECF)
Bloodstream
Lymphatic system
What is the immune system structure?
Large, complex and diffuse network of cells and fluids that penetrate into every organ and tissue
What is the reticuloendothelial system?
Network of connective tissue fibers that interconnects other cells and meshes with the connective tissue network surrounding organs.
What is the reticuloendothelial system inhabited by?
phagocytic cells, a mononuclear phagocyte system
what is a mononuclear phagocyte system?
macrophages ready to attack and ingest microbes that passed the first line of defense
What is the Lymphoid organs and tissues category classified as?
primary
secondary
what are the primary lymphoid organs?
sites of lymphocytic origin and maturation– thymus and bone marrow
what are the secondary lymphoid organs and tissues:
circulatory-based locations such as spleen and thymus and collections of cells distributed throughout body tissues- skin and mucous membranes–thymus, lymphnodes, spleen, miscellaneous
what is the thymus?
high rate of growth and activity until puberty, then begins to shrink; site of T-cell maturation
what are lymph nodes?
small, encapsulated, bean shaped organs stationed along lymphatic channels and large, blood vessels of the thoracic and and abdominal cavitites.
what is the spleen?
structurally similar to the lymph node, filters circulating blood to remove worn out RBCs and pathogens`
What is considered miscellaneous?
MALT GALT SALT BALT Appendix
what is MALT?
mucosal-associated lymphoidal tissue
what is GALT?
gastrointestinal-associated lymphoidal tissue (Peyer’s Patch)
What is SALT?
Skin-associated lymphoidal tissue
what is BALT?
Bronchial-associated lymphoidal tissue
What is hemopoiesis?
production of blood cells
what are stem cells?
undifferentiated cells, precursor of new blood cells
what are leukocytes?
white blood cells
what are granulocytes?
lobed nucleus
what are the different types of granulocytes?
neutrophils
eosinophils
basophils
mast cells
what is the function of neutrophils?
phagocytes
what is the function of eosinophils?
destroy eukaryotic pathogens
what is the function of basophils?
release potent chemical mediators (histamine)
what is the function of mast cells?
nonmotile elements bound to connective tissue. they release histamine
what are agranulocytes?
unlobed, rounded nucleus
what is the function of lymphocytes?
specific immune response (b and T cells)
3rd line of defense
what are B cells?
humoral immunity: activated B cells produce antibodies
what are T cells?
cell mediated immunity: activated t cells modulate immune functions and kill foreign cells
what are monocytes and macrophages?
largest of WBCs, kidney shaped nucleus; phagocytic
what are macrophages?
final differentiation of monocytes
what are dendritic cells?
trap pathogens and participate in immune reactions
what are the four categories of the first line of defense:
physical barrier
mechanical barrier
chemical barrier
genetic barrier
what is the physical barrier?
if intact, microbes cannot penetrate
what are the two layers of the physical barrier?
- outer layer of skin tight layer of epithelial cells
- mucous membrane coated with mucous with hairs or cilia
what is the mechanical barrier?
movement of cilia, flushing with urine or feces, blinking, coughing, sneezing
what is the chemical barrier?
chemicals associated with other barriers such as lysozyme, acid, salt, hydrochloric acid, digestive juices
what is the genetic barrier?
many microbes will only infect specific species. Parvo virus infects dogs and cats but not humans. Chickenpox virus infects humans but not dogs and cats
what consists of the second line of defense?
inflammation phagocytosis the complement system fever interferon
what is inflammation?
nonspecific defense response by the body to an injury to the tissue. It occurs after a cut, abrasion, bruise, burn or insect bite, and it aids in destruction of microbes and prevents spread, toxins and dead cells
what are the classic signs and symptoms of inflammation?
redness
warmth
swelling
pain
what is redness?
rubor–increased circulation and vasodilation in injured tissues in response to chemical mediators
what is warmth?
calor–heat given off by the increased blood flow
what is swelling?
tumor–edema; WBCs, microbes, debris, and fluid collect to form pus; prevents the spread of infection
what is edema?
increased fluid escaping into the tissue as blood vessels dialate
what is pain?
dolor–stimulation of nerve endings
what are the major events of inflammation?
injury, immediate reactions
vascular reactions
edema
resolution/scar formation
what is injury/immediate reactions?
cytokines released by tissue cells; vasoconstriction
what are vascular reactions?
vasodialation and seepage of fluid and out of vessels.
what is the major event edema?
infiltration of neutrophils (the first to arrive) and accumulation of pus
what is resolution or scar formation?
macrophages clean up/tissue is repaired (clean up crew)
what is pus?
dead cells
what are two unique properties of WBCs?
diapedesis
chemotaxis
what is diapedesis?
migration of cells out of blood vessels into the tissues
what is chemotaxis?
migration in response to specific chemicals at the site of injury or infection
what are cytokines?
chemical mediators that regulate, stimulate, and limit immune reactions produced by WBCs and damaged tissue cells
what are some examples of cytokines?
histamine
interleukin 1
interleukin 2
what is histamine?
produced by mast cells and basophils
produced during inflammation and allergy
causes vasodialation and increased permeability
what is interleukin 1?
produced by macrophages
produced during specific immune response
stimulates t cells and b cells
what is interleukin 2?
produced by helper t cells
produced during specific immune response
stimulates proliferation of t and b cells
what are the general activities of phagocytes?
- to survey tissue compartments and discover microbes, particulate matter, and dead or injured cells
- to ingest and eliminate these materials
- to extract immunogenic information from foreign matter
what cells are part of phagocytosis?
neutrophils
eosinophils
macrophages
how do neutrophils help with phagocytosis?
general-purpose; react early to bacteria and other foreign materials, and to damaged tissue
how do eosinophils help in phagocytosis?
attracted to sites of parasitic infections and antigen-antibody reactions
how do macrophages help with phagocytosis?
derived from monocytes; scavenge and process foreign substances to prepare them for reactions with B and T lymphocytes
what are toll-like receptors?
protein receptors within cell membrane of macrophages (PRRs)
what do toll like receptors do?
detect foreign molecules and signal the macrophage to produce chemicals to stimulate an immune response
what are pathogen-associated patterns (PAMPs)
molecules shared by microorganisms (peptidoglycan, outer membrane)
what is the mechanism of phagocytosis?
chemotaxis and ingestion
phagolysosome formation
destruction and elimination of debris
what is chemotaxis and ingestion?
phagocytes migrate and recognize PAMPs. They engulf microbe in a phagosome
what is phagolysosome formation?
lysosome fused with phagosome (death-30 minutes)
what is destruction and elimination of debris?
Destruction due to lysosome products: enzymes and reactive oxygen products
what is the complement system?
complex system that is involved at several levels of immunity. Consists of 26 blood proteins that work in concert to destroy bacteria and some viruses
what are complement factors?
proteins found in the blood stream produced by liver, lymphocytes and monocytes
the complement system works in:
a cascade reaction like blood clotting
the complement system is activated by
microbes, parts of microbes, cytokines and antibodies
what is the end product of the complement system?
membrane attack complex (MAC)
what is the membrane attack complex?
large, ring-shaped protein that digests holes in cell membranes of bacteria and some viruses
what is the function of the complement system?
MAC
acts as a chemotactic agent
stimulates inflammation
opsonization
what is opsonization?
coats the microbe and helps phagocytosis
what is the hypothalamus?
regulates body temperature to 98.6 degrees
what is fever?
initiated by circulating pyrogens which reset the hypothalamus to increase body temperature; signals muscles to increase heat production and vasoconstriction
what is pyrogen?
microbe products, blood products, vaccines and cytokines
sources of a pyrogen can be
exogenous or endogenous
what are the benefits of fever?
inhibits multiplication of heat sensitive microbes, prevents the nutrition of bacteria by reducing the availability of iron, increases metabolism and stimulates immune reactions and protective physiological processes
what is interferon?
small protein produced by certain WBCs and tissue cells
what are the three types of interferons?
interferon alpha
interferon beta
interferon gamma
what is interferon alpha?
lymphocytes and macrophages
what is interferon beta?
fibroblasts and epithelial cells
what is interferon gamma?
T cells
interferon is produced in response to
viruses, RNA, immune products, and various antigens.
interferon binds to:
cell surfaces and induce expression of antiviral proteins and inhibit expression of cancer genes
what happens if the body temperature is at 98.6 degrees and a pyrogen is present?
102 degrees and you will shiver and feel cold
what happens if you have a fever of 102 degrees and the pyrogen is absent?
your body temp will go back to 98.6 degrees and you will sweat and break the fever.
1st line is:
innate and nonspecific
2nd line is:
innate and nonspecific
3rd line is:
acquired and specific
what are natural killer cells
type of t cell with natural nonspecific cytotoxin powers
what do natural killer cells do?
circulate and are the first to destroy virus infected cells and tumor cells
where are natural killer cells found?
the spleen, blood, lungs, lymph nodes, bone marrow
what stimulates natural killer cells?
cytokines such as interferron
what is interferon?
cytokine produced in response to viruses, RNA, immune products and various antigens.
what does interferon do?
protects against viral infection of cells and cancer cells
what are the virulence factors of Neisseria influenza and Neisseria aeruginosa that inhibit the immune system?
they prevent MAC from creating holes in their surface.
what are the virulence factors of pseudomonas aeruginosa that inhibit the immune system?
it produces enzymes that inactivate complement factors
What is the third line of defense?
a dual system of B and T lymphocytes
what is an antigen?
molecules that stimulate a response by T and B cells
what are the two features that characterize specific immunity?
specificity
memory
what is specificity?
antibodies and killer cells produced function only against the antigen that they were produced in response to
what is memory?
lymphocytes are programmed to recall their first encounter with an antigen and respond rapidly to subsequent encounters
what are the major functions of the receptors?
- to perceive and attach to nonself or foreign monlecules
- to promote the recognition of self molecules
- to receive and transmit chemical messages among other cells of the system
- to aid in cellular development
all of our cells also have molecules present iin the cell membrane that
tell the immune system that they belong in the body
the composition of natural molecules is
genetically determined
one important set of natural molecules is:
major histocombalitity complex MHC
natural molecule receptors are found on all cells except:
red blood cells
what is class one MHC?
markers that display unique characteristics of self molecules and regulation of immune reactions
Class I MHC are required for
T lymphocytes
what is class 2 MHC?
regulatory receptors found on macrophages, dendritic cells, and B cells
Class 2 MHC are involved in:
presenting antigen to T cells
what are foreign molecules?
also called antigens
what is the property of behaving as an antigen?
antigenicity
what is antigenicity?
foreignness
shape
size
accessibility
what is the molecular composition of an antigen?
protein lipoprotein glycoprotein nucleoprotein polysaccharides
what are lymphocyte receptors?
lymphocytes role in surveillance and recognition is a function of their receptors
Foreign molecules can be part of
any part of a microbe
what are two types of lymphocyte receptors?
B cell receptors
T cell receptors
what are B cell receptors?
bind free agents not processed by APC
what are t cell receptors?
bind processed antigens together with the MHC molecules on the cells that present antigens to them basically processed by the APC
what is autoimmune disease?
when tolerance is not working and the immune system fails in distinguishing between self and non self
during autoimmune disease:
the body attacks its own cells
what are the two sides of the 3rd line?
t cells and b cells
what are b cells?
mature in bone marrow
become plasm cells
produce antibodies
provide humoral immunity
what are T cells?
mature in the thymus
become killer t cells
whole cell kills pathogen
procide cell mediated immunity
activation of the two sides of acquired resistance occurs in
5 stages
what are the five stages?
- clonal selection theory
- processing and presenting of antigen
- helper t cell activation
- b cell activation and antibody production/activated b cell
- cytotoxic T cell activation/activated cytotoxic t cell
what is clonal selection theory?
B lymphocytes and T lymphocytes undergo maturation before being ready to fight for the body. Lymphocytes produce a variety of receptors.
During clonal section theory, undifferentiated lymphocytes:
undergo a series of divisions and genetic changes that generate milliions of different cell types.
During clonal section theory, Both B and T cells:
undergo genetic changes to be able to respond to antigens
During clonal section theory, when becoming immunocompotent,
cells will have unique genes that will produce and place unique receptors on their cell surface
during clonal section theory, the unique receptor found on each of the cells
is what recognizes unique antigens
Clonal section theory is also called
lymphocyte development and differentiation
while lymphocytes are developing in the bone marrow,
lymphocyte stem cells differentiatie into eith T or B cells.
When lymphocytes are developing, B cells:
stay in the bone marrow while T cells migrate to the thymus
when lymphocytes are developing, both t and b cells:
migrate to secondary lymphoid tissue
while lymphocytes are developing, lymphocyte specificity is
preprogrammed, existing in the genetic makeup before an antigen has ever entered the system
While lymphocytes are developing, each genetically different type of lymphocyte
(clone) expresses a single specificity
what is clonal selection?
first introduction of each type of antigen into the immune system selects a genetically distinct lymphocyte and causes it to expand into a clone of cells that can react to that antigen.
what are the different parts of clonal selection theory?
the development of lymphocytes clonal selection B-cell maturation T-cell maturation Cooperation in immune reactions to antigens
where does B-Cell maturation occur?
at bone marrow sites that harbor stormal cells which nuture the lymphocyte stem cells and provide hormonal signals
During B-cell maturation, the cells have
immunoglobin as surface receptors for antigens
during b-cell maturation, the receptor placed on B cells is an
antibody molecule
IgM or IgD
During B-cell maturation, millions of distinct B cells develop and
home to specific sites in the lymph nodes, spleen, and GALT
During a B-cells lifespan, it will
come into contact with antigens
what are immunoglobins?
large glycoproteins that serve as specific receptors of B cells for antigens
T-cell maturation is directed by
the thymus gland and its hormones
what is the receptor on the t cell during maturation?
two parallel proteins
what is CD?
cluster of differentiation
During T cell maturation, there are
different classes of T cell receptors (CD)
During T cell maturation, mature t cells
migrate to lymphoid organs
the T cell receptors for antigens are formed
by genetic recombination with variable and constant regions
the t cell receptors for antigens are 2 parallel
polypeptide chains that are small and not secreted
The basis for all immune responses is the encounter
between antigens and white blood cells
lymph nodes and speen concentrate the antigens and
circulate them so they will comeinto contact with lymphocytes
what is the second stage of activation?
Processing and presenting the antigen
During Processing and presenting the antigen, microbes entering the body are recognized by:
immune system cells
the macrophage is:
the antigen presenting cell (APC) of the body
what is the function of the macrophage?
to engulf the microbe, digest it, amd put a part of the microbe on its surface to present to a lymphocyte
During processing and presentation T cell dependant antigens
must be processed by phagocytes called antigen presenting cells (APC)
Durinf processing and presenting, APCs,
modify the antigen then the antigen is moved to the APC surface and bound to MHC receptor
During processing and presenting, antigen presentation involves a direct collaberation among
an APC and a T helper cell
During processing and presenting, interleukin 1 is secreted by
APC to activate T helper cells
During processing and presenting, interleukin 2 is produced by
T helper cells to activate B and other T cells
what is stage 3 of activation?
Helper T cell activation (CD4 cell)
Helper T cell activation must be
activated forst by the macrophage
What is the first step of helper t activation?
physical stimulus: the physcial contact between helper t and APC (must include contact with the antigen)
what is the second step of helper t activation?
chemical stimulus: APC secretes interleukin 1
After the two steps of helper T activation,
now activated helper T can assist in activating B cell and other T cells
What are the fourth steps of activation?
B cell activation and antibody production
Activated B cell
During B cell activation, the B cell
phagocytizes and processes the microbe (no APC)
what is the first step that helper T activates the B cells?
Physical stimulus: physical contact between B cell and Helper T cell (must include contact with the antigen)
What is the second step that helper T activates b cells?
Chemical stimulus: Helper T cell secretes cytokine: interleukin 2. Now B cell is activated
Activated B cell undergoes change and produces:
plasma cell
memory B cell
what is the plasma cell?
produces antibodies
what is the function of antibodies?
opsonization
activates complement
antigen-antibody aggregates
neutrilization
what is opsonization?
augments phagocytosis
what is “activates complement”
MAC (membrane attack complex)
what is antigen-antibody aggregates?
causes large clumps, ties up microbe
what is neutrilization?
microbe cannot bind target cell
what is memory B cell?
lives long term in the lymph tissue and is activated when subsequent exposure occurs
what does memory b cell produce?
lots of antibody when activated
what are the five classes of antibodies?
IgM IgG IgA IgD IgE
what is IgM?
exists as a pentamer, circulates in blood. The first antibody produced by a plasma cell
what is IgG?
monomer, most prevalent antibosy in fluids. The second antibody produced by plasma cell and first antibody produced by memory cells
IgG provides:
long term immunity
IgG is the only antibody
that crosses the placenta
what is IgA?
monomer or dimer found at the surface of membranes (saliva, mucous, tears, colostrum)
IgA is also called
secretory IgA
what is IgD?
monomer, still a mystery. Only things known are that there are small amounts in blood and it serves as a receptor on immunocompetent B cells
what is IgE?
monomer, uncommon in blood unless one has allergy or parasitic worm infection; stimulates histamine release
Neissera meningidis and neissera gonorrheae produce
IgHase which digests IgA antibody
During the first exposure to a microbe, the plasma cell produces
IgM in first in smaller quantities
IgG second in larger quantities
During the second exposure to a microbe, the memory cell produces
LgG in large quantities (long term immunity)
What is the fifth stages of activation?
cytotoxic T cell activation
activated cytotoxic T cell
what is the first step of cytotoxic t cell activation?
physical stimulus: APC contacts cytotoxic T cell with antigen
what is the second step in cytotoxic t cell activation?
chemical stimulus: helper T cell secretes interleukin 2
what are the two cells produced by activated cytotoxic T cell?
Killer T cell
Memory T cell
what is killer T cell?
seeks out and destroys antigen containing celles with lymphotoxins
what are lymphotoxins?
??????
what is memory T cell?
lives long term in the lymph tissue and is activated when a subsequent exposure occurs
what are the different types of T cels?
T Helper cells Cytotoxic T cells Natural killer cells Supressor T cells Delayed hypersensitivity cells
what are T helper cells?
(CD4) most prevalent type of T cell
what is the function of helper T cells?
regulate immune reaction to antigens including other B and T cells; also involved in activated macrophages and increasing phagoctosis; differentiate into T helper 1 cells and T helper 2 cells
what are cytotoxic T cells?
they destroy foreign or abnormal cells by secreting granzymes and perforins that lyse cells.
what are natural killer cells?
lack specificity; circulate through the spleen, blood and lungs
what aresupressor T cells?
not well understood and are involved with dampening parts of the immune response by inhibiting proliferating B and T cells and are also iinvolved in immunologic tolerance.
what are delayed hypersensitivity T cells?
involved in certain allergic reactions
what are some examples of delayed hypersensitivity cells?
tuberculin skin tests
what seeks out and destroys antigen containing cells with lymphocytes during activated cytotoxic t cell?
granzymes and perforins
