Chapter 13 Flashcards
True or False
third line of defense is NOT innate but adaptive
True
immunocompetence
the ability of the body to recognize and react with multiple foreign substances
Antigen AKA immunogens
Any cell, particle or chemical that induces a specific immune respons by B cells or T cells and can stimulate resistance to an infection or a toxin
What are antigens made of?
Usually protein or polysaccharide molecules that reside on the surface or inside cells and viruses including our own
epitope
the precise molecular group of an antigen that defines its specificity and triggers the immune response
True or False
Antigens are highly individual and stimulate specific immunity
True
specificity
an immunity, the concept that some parts of the immune system only react with antigens that originally activated tehm
memory
the capacity of the immune system to recognize and act against an antigen upon second and subsequent encounters
Lymphocyte Development
divergence into two distinct types
B and T
which then constantly recirculate through the circulatory system and lymphatic system, migrating into and out of the lymphoid organs
What do phagocytes do to B and T cells?
They present antigens to them
Major Histocompatibility Complex (MHC)
set of genes that code for human cell markers or receptors
AKA human lekocyte system gives rise to glycoprotiens found in all cells except red blood cells
Class I MHC
appear on nucleated cells only
Class II MHC
regulatory markers, found in macrophages, dendritic cells and B cells present to T cells
Class III MHC
encode for protiens involved with complement system
CD molecules
“cluster of differentiation” Example CD3 CD8 CD$ surface molecules
Challenging B and T cells with antigens results in
proliferation and differentiation
memory and clone cells
T-Cells are considered what type of immunity
Cell-mediated immunity
B-cells are considered what type of immunity
Hummoral Immunity
Types of T cells
helper
regulatory
cytotoxic
Helpter T cells
activates macrophages, assists B cell processes and help activate cytotoxic T cells
Regulatory T cells
control the T cell response
Cytotoxic T cells
lead to the destruction of infected host cells and other “foreign cells”
B cells differentiate into
plasma and memory cells
Plasma cells release
antibodies
Antibodies attach to an antigen
marking it for destruction or neutralization.
Maturation of T cells occurs in
the thymus and GI tract
True or false
All T cells have CD3 molecules
True
CD4
accessory receptor protein on T cell that binds to MHC II
CD8
ONLY on cytotoxic T cells binds to MHC I molecules
Di George syndrome
birth defect of missing or defective thymus so no T cells
Severe Combined immunodeficiency
SCIDs birth defects that knock out both B and T cells
Where to B cells mature?
bone marrow
immunoglobulins (Ig)
chemical class of proteins to which antibodies belong
antigen binding site
specific regions at the ends of antibody that recognize specific antigens
variable region
antigen binding site fragment of an a immunoglobulin protien; consists of combination of light and heavy chains whose molecular configuration is specific to an antigen
colonal selection theory
a conceptual explanation for the development of lymphocyte specificity adn variety during immune maturation
Two important features of colonal selection theory
1 lymphocyte specificity is programmed, existing within genetic makeup before antigen has even entered the tissue
2 each genetically distinct lymphocyte expresses only a single specificity and can react to that chemical epitope
clone
colony of cells or organism derived from a single cell by asexual reproduction sharing ALL characteristics
Entrance on Antigens
an antigen/immunogen has to be a certain foreignness, shape, size and accessibility but mostly foreign
Materials considered to be antigens
proteins and poly peptides lipoproteins glycoprotiens nucleoproteins polysaccharide and lipopolysaccharide
protiens and polypeptides
enzymes, cell surface structures and exotoxins
lipoprotiens
cell membranes
glycoproteins
B cell markers
nucleoproteins
DNA complexed to protein but NOT pure DNA
polysaccharde
certain bacterial capsules
haptens
an incomplete or partial antigen. Although it constitutes the determinate group and can bind antigen, hapten cannot stimulate a full immune response unless it is carried by a larger protein molecule
Examples of haptens
drugs, metals, ordinary innocuous house hold, industrial and environmental chemicals
alloantigenic
an antigen present in some but NOT all members of the same species
basis for individuals blood group and MHC profile
superantigens
bacterial toxins that are potent stimuli for T cells and can be factor in diseases such as toxic shock
allergens
antigens that evoke an allergic reaction
antigen presenting cells (APCs)
cells of immune system that digest foreign cells and particles and display pieces of them on their own surfaces in such a way that other cells of immune system recognize them
dendritic cells
a large antigen processing cell characterized by long branch like extensions of the cell membrane
what does the CD4 attach to?
CD3
What marker to all T cells carry?
CD4
What to helper cells secrete?
interleukin 2`
What does interleukin 2 stimulate?
cytotoxic cells
How do helper cells activate macrophages
by releasing cytokines
virally infected cells
are recognized by cytotixic cells because of telltale viral peptides expressed on surface
Gamma Delta T cells
do NOT have recreptors rearranged to recognize antigens, work like WBCs do in nonspecific immunity
responsive to certian phospholipids and react against tumor cells
Natural Killer Cells (NK cells)
lack specificity for antigens, circulate blood, spleen and lungs first to attack cancer and virally infected cells
Steps of B cell activation
binding of antigen Antigen processing and presentation Bcell/Thelper cell cooperation and recognition Bcell activation differentiation colonal expansion
hypervariable region
the site of the antibody binding to the epitope is composed of this
varied amino acid content
Antibody functions
opsonization neutralization agglutination lysis antitoxins
colostrum
clear yellow early product of breast milk that is very high in secretory antibodies. Provides passive intestinal immunity high in IgA
titer
in immunochemistry a measure of antibody level in a patient
determined by agglutination methods
anamnestic response
an augmented response or memroy related to a prior stimulation of the immune system by antigen
boosts levels of immune substances
natural immunity
acquired during normal biological experiences
artificial immunity
immunizations, vaccines and immune serum
active immunity
antigen activates B and T cells
characteristics of active immunity
created memory cells for reexposure
several days to develop
lasts long time somtimes lifetime
can be acquired naturally or artificially
passive immunity
receiving immune substances (antibodies) that were produced actively by another human or animal
characteristics of passive immunity
lack of memory of antigen lack of antibody production against disease immediate onset protection short term effectiveness can be natural or artificial
variolation
hazardous, outmoded process of deliberately introducing small pox material scraped form a victim into non immune subject in hope of inducing resistance
vaccine
orignally used in reference to inoculation with the cow pox vaccinia virus
NOW pertains to injection of whole microbes (killed or attenuated), toxoids, or parts of microbes as a prevention or cure of disease
DNA vaccines
newer vaccine preperation based on inserting DNA from pathogens into host cells to encourage them to express the foreign protien and stimulate immunity
adjuvant
chemical vehicle that enhances antigenicity presumably by prolonging antigen retention at the injection site
Qualities of an effective vaccine
protect against exposure to natural, wild forms of the pathogen
low level of adverse side effects or toxicity and not cause harm
stimulate both antibody response and CMI response
long term lasting effects
NOT require numerous doses or boosters
inexpensive and have relatively long shelf life easy to administer
Whole cell or virus subcategories
live, attenuated cells or viruses ‘
killed cells or inactivated viruses
Part-of-organism preparations
sub units derived from cultures of cells or viruses
sub units chemically synthesized to mimic natural molecues found on the pathogens
sub units manufactured via genetic engineering
subunits conjugated with protiens to make them more immunogenic
conjugated vaccines
subunit vaccines combined with carrier protiens, often from other microbes, to make them more immnogenic
principle stages of immunity
lymphocyte development and differentiation
presentation of antigen
challenge of B & T cells by antigens
T cells response : CMI and B cell production of antibodies
Co-receptors of mature T cells
CD4 CD8
New strategies in vaccine production
antigen synthesis
gene cloning
recombinant DNA
Antibody binding sites and frequency(numbers)
IgA=4,2 13% IgG=2 80% IgM=10 6% IgD=2 1% IgE=2 .002%
dimeric
2 binding sites
CD8 receptor
cytotoxic T cells
Acellular vaccines
epitope based vaccines
IgG
long term immunity, opsonization and neutralize toxins bind to phagocytes
IgA
secretory antibody Ex) tears, saliva, breast milk, mucus and colostrum
IgM
first antibody produced in response to antigen
IgD
main function is to serve a B cell receptor
IgE
allergies, worm infections
mast cell and basophile binding
attenuate
reduce virulence of pathogenic bacterium or virus
Preperations that most vaccines are based on include
live attenuated microbes
pathogen derived antigens
killed cells or inactivated cells
genetically engineered microbes or their antigens
oral vaccine advantages
well tolerated
can stimulate secretory IgA
more readily accepted
easy to administer
Antibody class’s half life in serum
IgG 23 days IgA 6 days IgM 5 days IgD 2.5 days IgE 3 days
poor immunogens include
simple and small molecules and repeating polymers
main antigen presenting cells
dendritic B cells and macrophages
Memory T cells live the longest
true
T helper 1 cells functions
delayed hypersensitivity reactions
secrete cytokines
activation of CMI pathways
T helper 2 cells functions
drive B cell proliferation
Secrete cytokines
Antitoxin
can neutralize bacterial exotoxins
regulatory T cells
control specific immune response
prevent autoimmunity
vaccine administration routes
subcutaneous injection
intramuscular injection
intradermal injection
