immuno- L4: antibodies and humoral immunoresponse

humoral immune response

cell-mediated immune response

what are the 2 adaptive immune mechanisms?

humoral

are B cells are antibodies involved in the humoral or cell-mediated immune response?

B cells (and antibodies)

what cells are involved in the humoral immune response?

cell-mediated

are T cells involved in the humoral or cell-mediated immune response?

T cells (cytotoxic T cells and T helper cells)

______cells are involved in the cell-mediated immune response

the ability of the immune system to respond more quickly and effectively to specific pathogens that have been encountered previously

what is immunological memory?

immunological memory, a function of the humoral immune system

in the first attack of measles, adaptive immunity is too slow to prevent the virus from growing and causing symptoms. however, in a second attack, and antibody response is made so rapidly that the virus is disposed of before symptoms appear. this is an example of ...

memory T cells

B cells

antibodies

what cells play a role in immune memory?

-memory cells respond more quickly and aggressively and have an increased number

-memory cells have a different gene expression profile (ex- memory CD8 T cells have more mRNA of perforin than naive T cells)

- memory cells are more mobile (because there is a different pattern of expression of surface proteins that allow this)

-memory cells are able to maintain their number by continual low level proliferation

what are the differences between memory cells and naive cells?

antibodies

B cell receptors

T cell receptors

MHC

what are the immune recognition molecules?

antigens select and stimulate lymphocytes carrying receptors that are specific for that antigen- the selected lymphocytes proliferate more so are more concentrated

what is Burnet's "clonal selection" theory?

Burnet's "clonal selection" theory-

because lymphocyte 2 has the receptor for the antigen, it is selected and therefor proliferates

what theory represented here?

1. a B cell binds to the antigen for which it is specific

2. B cell proliferates and some become plasma cells or memory cells (usually with stimulation from a T helper cell)

3. the plasma cells proliferate and produce antibodies against the antigen

4. the memory cells can respond to any secondary encounter with the same atigen

describe the mechanism of the humoral immune response

1. a T cell binds to the MHC antigen complex on the surface of the infected cell, activating the T cell

2. activation of T cell releases cytokines which enhances to action of macrophages

3. CD8 T cells become cytotoxic T cells, which induce apoptosis of the target cell

describe the mechanism of the cell-mediated immune response

1. directly binding to the antigen (which does NOT induce antibody production)

2. binding to T helper cells

what are the 2 ways that a B cell can be activated?

1. the B cell Ig recognizes the epitope on the viral cell

2. the B cell internalizes and degrades the virus

3. peptides from the ingested virus go to the B cell surface (bound to MHC II) and are presented to the T cell, which activates the B cell

4. now, the B cell produces antibodies against the protein

explain what is occurring here

the T helper cell that has previously encountered an antigen binds to the B cell. it expresses CD40, which is the B cell stimulatory molecule, and secretes IL-4, IL-5, IL-6, which cause proliferation and differentiation of the B cell

explain what is occurring here

secreted by T helper cell in order to cause differentiation and growth of a B cell

what do IL-4 and IL-5 do, and who secretes them?

-regulates construction of antigen receptor

-ensures each cell only has one specificity

-checks and disposes of self reactive B cells

-exports useful cells

-provides a site of antibody production

what are the roles of the bone marrow in B cell development?

when it makes contact with developing B cell

what makes stromal cells of the bone marrow secrete cytokines that aid in B cell development?

this contact triggers the stromal cell to secrete cytokines that further aid in the development/maturation of the B cell

when the stromal cells of the bone marrow make contact with a developing B cell, what happens?

stimulated B cells

plasma cells develop from ________

lymph node cortex and paracortex, and marginal zones of the spleen

where are plasmablasts located in the body?

secrete Ig (antibody) molecules (up to 10,000 per second)

what do plasma cells do?

no

do plasma cells divide?

no, they die within a few days

are plasma cells long lived?

neutrilization of bacteria

opsonization

complement activation

what are the 3 roles of the antibodies released by plasma cells?

plasma cells

antibodies are secreted by....

adaptive

are antibodies a product of innate or adaptive immunity?

a unique antigenic epitope

antibodies are made specifically to bind to ....

yes, so that different antibodies can bind

can a virus have different antigenic determinant sites?

the number of binding sites it has

what is the valence of an antibody?

usually 2

how many binding sites does an antibody have?

monomer

Y shaped

4 protein chains- 2 light and 2 heavy

sections at the end of Y arms have antigen binding sites

the stem of the Y and lower arms are the constant region

the Fc region at the stem of the Y is where the Ab can bind to complement or cells

what is the structure of an antibody?

the end of the arms of the Y

which part of the antibody has antigen binding sites?

the stem of the Y

which part of the antibody is able to bind to cells/complement?

lower arms and stem of Y

which part of the antibody is the constant region?

blue

which part (color) is the constant region?

red

which part (color) is the antigen binding site?

an antibody

what is this?

the lower blue part (stem)

which part can bind to cells/complement?

2 antigen binding fragments

when the papain cleavage breaks to the disulfide bonds at the hinge region, it results in..

F (ab')2 molecules connected, and the rest fragments

when the pepsin cleavage breaks the antibody below the disulfide bond, it results in ...

IgG

what Ig is the major antibody of the secondary immune response?

IgG

which Ig is the only Ig that can pass through the placenta and protect the fetus/newborn?

enhance phagocytosis

neutralize toxins and viruses

protect fetus and newborn

what are the functions of IgG?

IgM

what Ig is the first antibody produced during an infection?

IgM

which is the "early antibody"?

IgM- composed of 5 Y structures

which Ig is this?

when the pathogen invades

when are IgM produced?

protects mucosa surfaces

provides immunity to the GI tract

what is the role of IgA?

IgA

which IgA provides immunity to the GI tract?

sIgA (secretory IgA)

what is the major Ig of secretions?

sIgA (secretory IgA)

what is this?

IgD

which Ig induces antibody production?

induce antibody production- initiate immune response by B cells

what is the main role of IgD?

IgE

which Ig is the main in allergic response?

IgE

which Ig is important in the lysis of worms/parasites?

lysis of parasites/worms

allergic reactions

what are the roles of IgE?

IgG

which is the most concentrated Ig?

IgE

which is the least concentrated Ig?