241 - 36, Immunogenetics Flashcards
When the immune system detects a self-antigen, causes an ________ disease
autoimmune
Immune function is carried out by specialized blood cells called _________, a type of white blood cell
lymphocytes
Most immune responses can be grouped into two major classes: ______ immunity and ______ immunity
humoral; cellular
_______ immunity centers on the production on antibodies by specialized lymphocytes called B cells, which mature in the bone marrow
humoral
_________ are proteins that circulate in the blood and other body fluids, binding to specific antigens and marking them for destruction by phagocytotic cells.
antibodies
______ immunity is conferred by T cells, which are specialized lymphocytes that mature in the thymus and respond only to antigens found on the surfaces of the body’s own cells.
cellular
__ lymphocytes produce antibodies; __ lymphocytes respond to antigens on cells
B; T
Immune system has the ability to recognize (HOW MANY?) foreign antigens
unlimited
Each mature lymphocyte is genetically programmed to attack (HOW MANY?) foreign antigens
one
there is a large pool of millions of different lymphocytes, each capable of binding only one antigen. When one of these lymphocytes encounters the foreign antigen and binds to it, that lymphocyte is stimulated to divide. The lymphocyte proliferates rapidly, producing a large population of of genetically identical cells (a clone). Called ______ ________
clonal selection
antibodies also called ___________
immunoglobulins
antibodies consist of __(#) polypeptide chains
4
there are 2 ______ and 2 _____ polypeptide chains on each antibody
light; heavy
Antibodies form a __-shaped structure
Y
______ bonds link the two heavy chains in the stem of the Y
disulfide
a _____ chain attaches to a heavy chain in each arm of the Y.
light
Binding sites for antigens are where . . .
the ends of the branches of the Y
In the maturation of a lymphocyte, the segments are joined together to create an _________ gene
immunoglobulin
antibody genes are composed of ________
segments
The particular copy of each segment in an antibody used is ______.
random
For the light chain, a __ (______, 35 different ones in human) segment is joined to a __ (_____, 5 different ones in human) segment
v (variable); j (joining)
______ _________ joins the v (variable) and j (joining) segments in a light chain
somatic recombination
the heavy chain is joined by what segments . . .
v (variable), j (joining), d (diversity)
Somatic recombination is brought about by _____ and _____ proteins
RAG1 and RAG2
RAG1 and RAG2 (somatic recombination) generate . . . at specific nucleotide sequences that flank the V, D, and J gene segments.
double-strand breaks
DNA _____ _______ join the ends of particular segments together after the double strand break (somatic recombination)
repair proteins
all lymphocytes originate where in the body
bone marrow
B & T cells come to maturity where in body?
B - bone marrow
T - thymus
T vs B cell function
T - attack directly
B - produce antibodies
each arm of the Y (light chain locus) contains one set of these 3 genes
V, J, C
number of V, J, and C segment in germ-line DNA (light chain locus)
V = 30-35 J = 5 C = 1
rearrangement of V, J, C requires . . . (2) (light chain locus)
RAG1 and RAG2
in gene loci, V stands for . . . and C stands for . . . the J . . .
V - variable region
C - constant region
J - joins
_______ immunity is in reference to B cells
humoral
_______ immunity is in reference to T cells
cellular
difference between primary and secondary immune response
primary - 1st attack a disease (clones made)
secondary - disease returns, memory cells in circulation, rapid response
memory cells are found in PRIMARY / SECONDARY immune response
secondary
the 2 heavy chains are linked and the light to the heavy chains are linked by . . .
disulfide bonds
the immune response requires that T-cells bind to what 2 antigens . . .
foreign antigen and histocompatability antigen
. . . . encode proteins that provide specific identity to the cells of each individual organism (ensures autoimmune response doesn’t happen)
major histocompatability complex (MHC)
diversity of immunoglobins (antibodies) provided by (3)
somatic recombination
junctional diversity
hypermutation
. . . - accelerated random mutation of the variable (V) gene, cause diversity of immunoglobins
hypermutation
. . . - small deletions or insertions and frameshifts in the small antibody arm, causes diversity of immunoglobins
junctional diversity
. . . - combination of different joining (J) and variable (V) regions in chromosomes, causes diversity of immunoglobins
somatic recombination
