Chapter 17 Part 2 Flashcards
the immune response
What are the three effector functions of the antibody molecules?
- bind to and neutralize a bacterial toxin
- opsonization: coat the pathogen to promote phagocytosis
- activate complement
What is the structure of antibody?
Both contain one constant and one variable region
- 2 heavy chains (inner and long) (3/4 domains)
- 2 light chains (outer and short) (one domain)
- bonded by disulphide bonds
- Fab fragment (heavy inner, light outer)
- Fc fragment (heavy chain and bonded to cell like root)
another name for antibody
immunoglobins
What is a polyclonal response
when antigen have multiple different epitopes each B cells must make different antibodies for ONE antigen
another name for the hypervariable region on antibody
complementary determining regions (5-10 amnio acids)
where are the 6 hypervariable chains on an antibody
on the Fac fragment
What are the 3 steps in antigen recognition diversity?
1) somatic recombination
2) junctional diversity
3) combinational diversity
Explain Somatic Recombination
The heavy chain is chosen first
- different V, D & J segments are joined to create a variable region
Light chain is chosen after
- different V and J segments are joined together
Explain junctional diversity
new nucleotides are added into the V and J segments of the light chain and D and J on the heavy chain
Explain combinational diversity
different light chains are combined with already generated heavy chains
What are the five classes of antibodies?
- IgM
- IgG
- IgE
- IgA
- IgD
Where and when does the switching into a different class of antibody taking place?
germinal centre of lymph nodes after B cell activation
Which receptor (immnoglobin/antibody) is released first?
IgM
what differentiates the class of antibodies?
their light chains
how does a helper T cell help activate a B cell to secrete an antibody?
it sends the B cells to the germinal center of the lymph node to be class/isotype switched
why is the IgM the first antibody to be secreted?
it is the default antibody, it doesn’t get changed unless it is sent to the germinal center by the Helper T cell
What is somatic hypermutation?
B cells are sent to the germinal centre where they change the antibodies of B cells so they generate an antibody with higher affinity of the antigen
What does affinity maturation mean?
what it is called after the B cell has undergone somatic hypermutation and now are selected to under class/isotype switching helped by the helper T cells
What is a clonal selection hypothesis?
after activation the B cell will multiply itself
Where does T cell maturation take place?
thymus but they originate in the bone marrow
what does MHC restriction mean?
when T cells recognize self antigens (they get eliminated in thymus)
how do t cells get activated?
by dendritic cells
What is herd immunity?
when majority of a population is immune to a virus so they chance of someone susceptible to the virus catching it is low
what is a plasma cell
short lived B cells that produce large amount of antibodies
what is a memory cell
activated B cells that remain in the lymphoid tissue in case the antigen reappears in the body
where the 2 stages of the adaptive immune response?
1) Humoral- antibody secretion
2) Cell Mediated - killing infected cells
