immunology test 2

antibody

secreted form of b-cell receptor

where antibodies circulate

in the blood and lymph

type of surface where antibodies always cover

mucosal surfaces

what kinds of antigens do antibodies recognize the most

protein and carbohydrate antigens

what do antibodies do to antigens once they bind

• disable/neutralize them

• make them susceptible to destruction

each antibody only binds to…

one antigen or a few structurally related antigens

antibody diversity

antibodies can recognize large amounts of antigens

antibody repetoire

the total number of distinct antibodies that the body can produce
approximately 10^9 in humans

approximate antibody repetoire in humans

10^9

agammaglobulinemia

• inability to make antibodies

  • very susceptible to infection

what is responsible for XLA

BTK, a kinase

it’s present on the x-chromosome

immunoglobulin

antibodies and b-cell antigen receptors

naive mature b cells

mature b cells that have not made contact with an antigen yet

have membrane-bound immunoglobulin

1) mature naive b cell

2) b cell encounters antigen

3) stimulated b cells produce antibody secreting plasma cells

plasma cell

effector b lymphocytes that produce and secrete antibodies

clonal selection

when stimulated b cells produce plasma cells that produce identical antibodies specific towards the antigen bound

heavy chain

50kda

form the stem of antibody and part of the arms on the y

light chain

two identical 25kda polypeptide chain

antibody composition

2 heavy chains

2 light chains

carbohydrate attached to heavy chain

1) light chain

2) heavy chain

3) disulfide bond

4) carbohydrate

variable regions of antibody

• amino terminal regions of heavy chain

  • amino terminal of light chain

constant regions of antibody

everything that is not the amino terminus of heavy/light chain

what are variable regions

• domains with sequence diversity

  • determine antigen specificity

what are constant regions

• domains with limited variation

  • provide structural stability and effector function

what is the antigen binding site

region within variable region that directly binds to antigen

determines specificity

flexible hinge region

• bendable part of antibody

• connects antigen binding arms to stem

• lets arm adjust angles to bind to antigens in many different positions

the 5 different antibody isotopes

IgG
IgM
IgD
IgA
IgE

the light chain isotopes

kappa
lambda

IgG

IgM

IgD

IgA

IgE

the differences in antibody isotopes

• the length of constant heavy chain regions

• locations of disulfide bonds linking chains

• presence of hinge region

  • distribution of carb groups

antibody isotopes that have a hinge region

IgG, IgA, IgD

antibody isotopes that don’t have hinge region

IgM, IgE

what form do all immunoglobulin classes exist as when membrane bound

monomers

what form is IgD when secreted

monomer

what form is IgE when secreted

monomer

what form is IgG when secreted

monomer

which immunoglobulins are only monomers when secreted

IgG, IgE, IgD

what form is IgA when secreted

monomer and dimer

what form is IgM when secreted

pentamer

how many new b cells do bone marrow stem cells produce daily

more than 60 billion

what do b cells go through before becoming a plasma cell or a memory b cell

defined developmental stages

what do the first three stages of b cell development do

• development of b cells in bone marrow

  • first elimination based on b cell receptor formation

what do the last three phases of b cell development correspond with

• development of b cells in secondary lymphoid tissue

  • and the binding and attacking pathogen

list the phases of b cell development in order

1) repetoire assembly
2) negative selection
3) positive selection
4) searching for infection
5) finding infection
6) attacking infection

what happens in repetoire assembly and what number stage is it

first stage

• b cell receptors are developed and clonally expressed in the bone marrow

what happens in negative selection and what number phase is it

second phase

• b cell receptors that bind to human body are altered/eliminated/inactivated

what happens during positive selection and what number phase is it

third phase

• some immature b cells are sent to secondary lymphoid tissues to mature

what happens during search of infection and what number phase is it

fourth phase

• mature b cells circulate in blood, lymph, and secondary lymphoid tissue

what happens during finding infection and what number phase is it

fifth phase

• antigens from pathogens activate b cells, stimulating clonal expansion

what happens during attacking infection and what number phase is it

sixth phase

• b cells differentiate into plasma cells and memory b cells

where do b cells go after leaving bone marrow

lymph nodes, spleen, peyer’s patches, and other secondary lymphoid tissue in the respiratory tract

b cell receptor formation is dependent on what type of cell

stromal

1 b cell precursor

2 cytokines

3 stromal cell

1 hematopoetic stem cell

2 lymphoid progenitor

3 b cell precursor

4 pro-b cell

pro b cell

• earliest cell in b cell lineage

• have some capacity of cell renewal

• divide to produce more pro b cells

  • go onto further stages for differentiation

how can the exact phase of b cell development be identified

the different combinations of cd proteins on surface