B Cells and Humoral Immunity Flashcards
(blank) is a state of severe hypertension and spasticity in which an individual’s head, neck and spinal column take a complete “bridging” or “arching” position. This posture is caused by spasm of the axial muscles along the spinal column.
opisthotonus
(blank) is a highly fatal disease of humans. Mortality rates reported vary from 40% to 78%. The disease stems from a potent neurotoxin produced when spores germinate and vegetative cells grow after gaining access to wounds. The organism multiplies locally but symptoms appear remote from the infection site.
Tetanus
What is the causative agent of tetans?
clostridium tetani (found in heavily manured soil and GI of animals)
Why is tetanus vaccination so important?
because natural recovery from this disease is unlikely because it doesnt ellicit an immune response, you just die
In humoral immunity, what are the effectors of protection?
antibodies
How can you distinguish between humoral vs. cellular immunity?
adoptive transfer tests
(blank) is transferred by serum containing antibodies or by antibodies aone ( rattle snake venum, tetanus toxoid)
humoral immunity
(blank) is transferred only by cells (usually done in completely inbred mice or rats)
cellular immunity
How is humoral immunity transferred?
by serum containing antibodies by antibodies alone.
If you are transfering humoral immunity wthin a species, what happens?
they are accepted as self and are considered effective
What happens if you transfer antibodies across species?
antibodies last 5-7 days because they are immunogenic (elicit an immune response)
Is the transfer of antibodies awesome? why?
yes because it is practical and safe. Antibodies are human “self” and Ig can be irradiated to prevent viral infection
What is this:
an immune response that is not elicited by antibodies but rather antigen sepcific T cells and is tranferred only cells.
Cellular immunity
Why cant you really transfer T cell immunity?
because its hard to match MHC I and MHC II antigens and if they are not matching those cells will be killed
What three things influence humoral immunity?
amount of antigen, route of natural or prophylactic immunization, use of adjuvants
How long do specific antibodies live?
maintained for life, although concentrations drop slowly.
The affinity and concentration of an antibody is sometimes critical. Explain this as a priniciple for tetanus toxin/
antibodies for tetanus toxin nee to have an extremely high affinity and concentration in order to out-compete the toxin, this is why the tetanus vaccine is repeated.
What are immunogens?
molecules that elicit an antibody response
What are some common immunogens?
proteins > 25 micrograms (toxoids), killed pathogens, live attenuated viruses, conjugate and DNA vaccines.
What are adjuvants?
something that is added to improve immunizations but it itelf is not immunogenic.
What can adjuvants activate?
they can activate macrophages to secrete IL-1 and TNF alpha to activate helper T and B cells AND they keep immunogens localized
Routes of administration of vaccine or immunization affects the types of antibody made.
intramuscular?
Oral or intranasal?
IV?
IgG
IgA
poor route of immunization
If you repeatedly expose someone to a antigen what will happen?
you will increase the quantity and affinity of IgG and IgA
(blank) is a measurement of the binding strength of Fab antigen-biding site for its single antigenic epitope.
affinity
expressed as Ka=1/Kd
(ka= affinity, Kd= concentration to fill half the binding sites)
(blank) is a measurement of the total combined binding strength of a complete immunoglobulin molecule for a complex antigen that contains repeating epitopes.
avidity.
(think of this like velcro, one tooth of velcro wont have any strength, but numerous teeth of velcro create a very strong connection)
Explain how you can have low affinity but high avidity
an IgM antiody molecule with low affinity for a particular antigen (but that has 10 antigen binding sites) will bind with high avidity to a complex antigen that contains repeats of the epitope
(blank) becomes medically important for IgM and IgA because bacteria and viruses have repeating epitopes and proteins in the membranes, flagella, and capsules
avidity
WHy is antibody super important for botulin toxin, ebola virus, and tetanus?
Because these are very lethal in small concentrations so you must have high affinity to be able to bind even the smallest dose. (need to outcompete toxin for binding site)
How do you classify an immunoglobulin?
5 classes denoted by english letter (A-E)
Greek letters to describe heavy chains AND
Numbers for the isotypes
2 for IgA
4 for IgG
2 types of light chains called Kappa and Lambda
How many J chains are there for every polymeric unit (i.e immunoglobulin)
1 (think of it like a clasp of a necklace)
How do you determine the molecular weight of a immunoglobulin?
multiply each repeate by 150,000. (important because determines whether it can get out of the blood into tissues. greater than 50,000 cant get out of the kidneys, things that are smaller can.
How many antigen bining sites are on a pentameric Ig?
10, times each unit by 2
What is the first antibody made in immune responses and appears right after antigen is introduced?
IgM
Does IgM have a low or high affinity for antigens?
low affinity, but potential for high avidity
What is the serum concentration of IgM?
1.2 mg/ml
What is the serum half life of IgM?
about 5 days
What is the function of IgM?
fixes complement extremely well. Just 1 IgM antiboy on a bacterium can start complement killing
Is IgM made for life?
nope, it is termporary and tells you if you have had a recent infection or not
Where can you find IgM?
in secretions :)
What size is an IgG?
150Kd