Lecture 9: Adaptive Immunity Flashcards
the adaptive immune system is… (3 things)
acquired
very specific
has a memory
the adaptive immune system is ______:
Begins as soon as a pathogen is encountered for the very first time
Adaptive response will not occur until a pathogen is encountered
acquired
the adaptive immune system is ______:
Very targeted to a specific feature of a given bacterium, virus, toxin
Immunity to one pathogen will not confer immunity to another
very specific
the adaptive immune system has ______:
Produces a more effective response when a pathogen is encountered for the
second time-faster and stronger
a memory component
what two components does our adaptive immune system consist of?
humoral (antibody mediated) immunity
cell mediated immunity
______: Proteins produced by the immune system that bind and inactivate foreign
antigen
antibodies
______: Any foreign material that has the ability to active the adaptive immune system
* Normally protein, polysaccharide, lipid material
immunogens
_______: The actual portion of the antigen that binds to the antibody
* A single antigen will have more than one ______
* Increases the ability of an antigen to activation the immune system ->
immunogenicity
* Each _____ requires a distinct antibody
epitope
T/F: immunogens are always the same in every person
false! ex: some people will die if they eat peanuts, other love peanut butter
depends how much something can activate a unique immune system in individual people
______: Low molecular weight compound that is too small on its own to activate
adaptive immunity
* Not immunogenic
* Can bind to other molecules such as protein in blood and tissues
* Becomes strongly immunogenic
* An allergy forms
* Ex) penicillin
hapten
how do hapten activate an immune response to destroy something?
piggybacks onto something bigger than itself
_____ are glycosylated protein molecules
Antibodies (Ab)
antibodies are also called…
immunoglobulins
______: Consist of 4 subunits
* Two identical heavy chains
* Two identical light chains
* Chains are assembled creating three distinct
regions
* 2 identical variable regions (Fab regions)
* Provide the specificity of the _______
* 1 constant region (Fc region)
* Allows for interaction with immune cells
* Based on differences in the Fc region there are five different types of _____
antibody
what makes the light chains of an antibody light?
they’re smaller, have less amino acids
what is the role of the Fab regions on an antibody
interact and engage with the bad guy
two Fab regions are symmetrical and identical… the substrates they bind too must be…
identical regions on identical particles, highly specific!
_____ allows for interaction with immune cells and antibodies
Fc region
what are the five different types of antibodies?
IgM
IgG
IgA
IgD
IgE
______: Pentameric
* Five different antibody units
* Always the first antibody to be produced in response to an antigen
* Primary antibody response
* Found on the surface of B lymphocytes
* Remains in the blood
* Unable to enter the tissues
* Low affinity for antigen
* Very good at agglutination
Immunoglobulin M (IgM)
what is the first antibody ALWAYS produced?
IgM
what does it mean that IgM has low affinity for antigens?
doesn’t hold on as strong, weak bonds so not aggressively holding onto antigen
how many antigens can an IgM antibody hold onto?
10
_____: Monomer
* Most predominate antibody in the blood
* Also present in the tissues
IgG
which antibody is the serum form of antibodies?
IgG
crosses placenta!
T/F: IgG has strong affinity for antigens
true! found in tissue and in plasma
______: Dimeric
Secreted at mucosal sites
* Saliva, tears, mucous
* Important defense against respiratory, reproductive, digestive tract infections
IgA
how many antigens can an IgG bind?
2
how many antigens can an IgA bind?
4
______: Monomer
* Located on the surface of B cells
* Important in activation of B cells to begin producing antibody against a specific antigen
IgD
how many antigens can IgD and IgE bind?
2
T/F: B cells create one specific Fab each, highly specific
true!
_______: Monomer
* Binds to receptors located on the surface of mast cells and basophils
* Binding of ____-antigen complex triggers
degranulation and histamine release
* Allergy
IgE
what are the five major antibody functions?
neutralization
opsonization
agglutination
antibody mediated cytotoxicity
complement activation
_______: Antibodies bind to antigen blocking attachment
sites (“bearhug”)
* Prevents bacteria, virus and toxin entry into
tissues and host cells
neutralization
do you need to perform another step after neutralization using antibodies?
yes! doesn’t actually destroy anything so you need another step to finish killing bacteria/virus
______: Antibodies coat the surface of the bacterial
cell
* Attracts phagocytes
* Greatly enhances the rate of phagocytosis
* Phagocyte has the ability to interact with
the Fc region of the antibody
Opsonization
how are phagocytes attracted to perform phagocytosis using opsonization?
they recognize the Fc region sticking out when Fab region is bound to bacterial cell
T/F: Phagocyte does not have the ability to interact with
the Fc region of the antibody
false!
______: Each class of antibody can bind to a minimum of 2
identical antigen units
* Clumps together many antigens
* Allows phagocytosis to occur more efficiently
Agglutination
which antibody is best at performing Agglutination
IgM, 10 binding sites!
______: Attachment of antibody to parasites recruits
eosinophils
* Eosinophils attach to the Fc component of
antibodies
* Activated eosinophil releases reactive oxygen
species and hydrolytic enzymes
* Parasite is destroyed
Antibody mediated cytotoxicity
_______: a system consisting of a series of
proteins found in the blood
* Can be activated by antibody that is bound to
a bacterial cell
- Create a number of different immune responses
when activated - MAC attack complex forms
- Inserts into the membrane of bacterial
cell forming a pore - Contents of the cell leak and the bacterium dies
complement activation
what happens when a bound antibody triggers a complement activation?
changes inactivated protein into active form, causes downstream domino effect!
T/F: there are over 30 response proteins in body waiting to find something to cause complement activation
true!
____ are antigen presenting cells
B cells
_____ and _____ also perform antigen presentation, like B cells
Macrophages and dendritic cells
T/F: All antigen presenting cells can insert MHC II into the plasma membrane
true
what are the steps in antibody production?
- B cell phagocytoses exogenous antigen
- T helper cells bind to MHC II-Antigen complex resulting in T helper cell activation
- Some of these newly produced B cells will become plasma cells
T/F: antibodies secreted by proliferated B cells are specific to the original exogenous antigen
true! identical antibody proteins when B cells proliferate
newly produced B cells during an immune response become… (2 types)
plasma cells or memory cells
T/F: memory cells produce antibodies during current immune response
false
______: Occurs the very first time a specific antigen is encountered
* Can be a natural encounter or an artificial encounter (ex:
vaccination)
* Produces a weak antibody mediated response
* Slow production of low levels of antibody
* Results in the production of memory B cells: major goal
primary antibody response
______: Occurs every additional time
(after the primary response) a specific antigen is
encountered
* Produces a strong antibody mediated response
* Rapid production of high levels of antibody
* So rapid that the pathogen will not be able to
establish infection
* No disease occurs
secondary antibody response
how long does a primary antibody response take?
7-10 days ish
how long does a secondary antibody response take?
1-2 day ish
_______ prevents immune responses against self-antigens
Tolerance
______: Any immune cells that are found to recognize self-antigens are destroyed early on in development
* Helps to prevents auto-immune disease
tolerance
______: Recognizes and destroys abnormal cells present in the body
* Cells infected with virus or obligate intracellular bacteria
* These are endogenous antigen because they are present inside of the host cell
Cell Mediated Immunity
cell mediated immunity involves what type of cells?
cytotoxic T cells
Diseased host cell will display endogenous antigen in the plasma membrane complexed together with ______
* Cytotoxic T cells will bind to _____-Antigen complex using their T cell receptor
(TCR)
* This results in activation of the cytotoxic T cell
triggering it to release perforins and granzymes
that cause death of the infected host cell
MHC I
what two things specifically cause the death of infected host cells
perforins and granzymes, released by cytotoxic T cells
T/F: In order to clear a viral infection both antibody
mediated immunity and cell mediated immunity
are required
true! because viral infections are found both within cells and outside of cells (because they jump from host cell to host cell)
