Antibody Function Flashcards
what is the name of the strength of the interaction between an antibody and antigen that involves a SINGLE antigen-binding sites, versus MULTIPLE antigen binding sites?
-Affinity
-Avidity
how many epitopes can the immune SYSTEM target on the same antigen particle??
-several
What is the primary response?
the resulting immune response the first time an animal encounters an antigen
-IgM are primarily generated by plasma cells
What are the antibodies present on naive B cells?
IgM (main one- and they are in monomer form) and IgD
- tehir epitope specificity is IDENTICAL
What are the antibodies present in mature B cells?
IgG, IgA, OR IgE
-only one class of these is present
What is a memory/second response?
second exposure to same antigen
What is the memory response characterized by?
A shorter lag phase than a primary response, meaning the time between
exposure to antigen and the production of antibodies is less. (During the lag
phase, those B-cells that recognize the antigen must be exposed to the
antigen, then triggered to proliferate and subsequently take on effector
functions to secrete antibody before significant levels of antibody will be
present in serum.)
- A larger amount of antibody is produced.
- A larger proportion of so-called “switched isotypes” (IgG, IgA and IgE) will be
present. (During a primary response, plasma cells mostly secrete IgM
pentamers. During a memory response, plasma cells may secrete either IgG,
IgA, or IgE. This change in antibody class produced is referred to as class
switching.) - The antibodies of the memory response will be of higher affinity than those of
the primary response. (This is due to somatic hypermutation, which will be
explained in a subsequent lecture.)
What triggers B cell activation ??
activation is activated by the signaling brovided by IG-ALPHA AND IG-BETA that are associated with BCR
IT IS NOT THE ACT OF JUST BINDING
How and which antibodies can carry neutralization? what makes a good neutralizer?
-inactivation of TOXINS, VIRUS, and BACTERIA
-the ability of antigens to infect cells is inhibited by the binding of the parts of their molecules that are essential for attaching to cell with the binding of antibodies to it
-IgG and IgA are the Most important for neutralization
- not all antibodies are neutralizing to all viruses
Fab dependent
How and which antibodies can carry agglutination? what makes a good agglutination?
-antigens are clumped together by antibodies clumping them together, therefore making them more susceptible for phagocytosis.
-most efficient is IgM do to the quantity of binding sites
How and which antibodies can carry opsonization? what makes a good opsonization?
-when Fabs bind to a bacteria (coating it) leaving their Fc receptors open. therefore this calls MACROPHAGES and NEUTROPHILS to phagocyte the bacteria
-IgG is MOST important as phagocytes have FcG receptors
How and which antibodies can carry ADCC what makes a good ADCC? (Antibody-dependent cellular cytotoxicity)
-IgG binds to VIRALLY INFECTED CELLS, and since NK cells have high affinity to them, they will bind to IgG Fc’s and:
-use PERFORIN to perforate the virus, and then GRANYZYMES to trigger apoptosis in the virus.
What is the difference between ADCC and opsonization?
opsonization is eating of ORGANISIMS, and ADCC is killing of A HOST CELL (phagozytacion vs.apoptosis)
How and which antibodies can carry Mast cell degranulation?
- mast cells will BIND to IgE BEFORE IT BINDS to an antigen but to their high affinity of FcE regions
-then they bind to antigen and eat to degranulation where HISTAMINE is released
-DEGRANULATION leads to inflammation (main mechanism of allergy) AND recruits EOSINPHILS (which protect against parasites)
What is the Complement system, what is its function, and what antibodies activate it?
IgG and IgM dependent (after they bind on antigens)
series of serum proteins that mediates host defense against various extracellular pathogens, especially bacteria.
One effect of the complement system is to amplify the inflammatory response.
* Complement releases chemoattractants which direct the migration of phagocytic cells towards the site of complement activation.
*Another effect of complement proteins is to form pores in bacteria cell walls and membranes, causing the bacteria to swell with fluid to the point
that they burst.
Both IgG and IgM antibodies can activate the complement system
COMPLEMENT is typically directed AGAINST BACTERIA
What antibodies are in the plasma, mucosal surfaces, submucosal tissue, and B cell membranes?
IgA is also present in milk
-IgE and IgD in low qualities in the serum
what are these Ig functions dependent on?
What are the distributions gf antibodies in the plasma/serum? and why is IgG the most prevelant?
-IgG is made in the HIGHEST amount in the secondary immune response AND
- ITS HALF LIFE IS THE LONGEST
