L4 aquired immunity

epitope

• particular parts of antigen that is recognized by immune system

True or false: an antigen usually has many antigenic determinants or epitope

true

haptens

• small foreign molecules that consist only a single determinant group

• not immunogenic unless attached to a larger carrier

  • carrier grp contribute to size of the complex and enhances the orientation of antigen

Alloantigens

• cell surface markers and molecules that occur in some members of the same species but not in others

  • determine blood groups and histocompatibility in transplantation → it’s the reason why transplant reject

superantigens

potent T cell stimulators - provoke an overwhelming (and often dangerously strong) immune response

• can lead to toxic shock (ex. tampons)

Allergens

antigen that evoke allergic rxn

autoantigens

molecules on self tissues that sometimes will elicit an immune response due to failed tolerance

• ex. autoimmune disease

APC cells

• macrophages

• dendritic cells

• Bcells

T cells: site of maturation

thymus gland

T cells: immune surface markers

• T cell receptor

• CD molecules (like CD4 - helper; CD8 cytotoxic)

• MHC1 receptors

T cells: Circulation in blood relative number compared to B

high number

T cells: receptors for antigen

T cell receptor (TCR)

T cells: distribution in lymphatic organs

paracortical site (interior to the follicles)

T cells: require antigen presented with MHC? (APC)

yes

T cells: effector cells

helper and cytotoxic T cells and memory cells

T cells: general function

• regulate immune function

• kill foreign and infected cells

  • synthesize cytokines

B cells: site of maturation

bone marrow

B cells:

B cells: immune surface markers

• immunoglobulin MHCI and MHCII receptor

B cells: circulation in blood numbers compared to T cells 

Low number

B cells: receptors for antigen

immunoglobulin D and M

B cells: distrubiton in lymphatic organs

cortex (in follicles)

B cells: require Antigen presented with MHC (APC)

no

B cells: effector cells

plasma cells and memory cells

B cells: general functions

• produce antibodies to target, inactivate and neutralize antigen

T helper cells

• primary receptor on T cells

• function/important feature

• CD4

function

• activate other CD4 and CD8 (T cyt) cell

• secrete IL2, TNF, interferon gamma

• responsible for delayed hypersensitivity

• interact with MHC II receptors

T helper cells 2

• primary receptor on T cells

• function/important feature

• CD4

function

• drives B cell proliferation

• secrete IL4,5,6,10

• can dampen TH1 activity

T reg

• primary receptor on T cells

• function/important feature

• involve in development of immune tolerance

• suppression of pathological immune responses, inflammation, autoimmunity (“reduce excess immune reaction”)

T cytotoxic cell

• primary receptor on T cells

• function/important feature

• CD8

Function

• lysis target foreign cell

• destruction of cancer cells, virus infected cells

• graft rejection

• requires MHCI for function may have some regulatory function

neutralization

• antibody react w/ surface molecules of bacteria/viruses → prevent them from attaching to surfaces or cell receptor

• also can neutralize enzymes or toxin involved in disease pathogenesis

ex. covid - vaccine create Ab attach to spike protein of covid

bacteria and virus needs to attach, without they can’t enter cell

Opsonization

• coating microorganisms or other particles w/ specific antibodies → recognized by phagocytes → engulfed/destroyed

agglutination

crosslinking cells or particles with antibody into large clumps

precipitation

aggregation of soluble or finely particulate antigen with antibody

complement fixation

activate of classical complement pathway → result in specific rupturing of cells and some viruses

IgG

• shape

• function

• prevalance

• monomer → 2 antigen binding

function

• long term immunity

• neutralize toxins and viruses

• produced in plasma cells by primary response; in memory cells via secondary response (memory antibody)

prevalance

• MOST prevalent (80% in total antibody serum)

IgA

• shape

• function

• prevalance

• monomer circulates in blood → 2 antigen binding

• dimers in mucous and serous secretion → 4 antigen binding

type

• secretory antibody

Prevalence in serum

• 13% 

IgM

• shape

• function

• prevalance

• 5 monomers (pentamers) → 10 antigen binding sites

function

• produced at first response to antigen

• can serve as b cell receptor

prevalence and size

• 6%

• biggest

IgD

• shape

• function

• prevalance

• monomers → 2 antigen binding site

Function

• serve as receptor on B cells for antigen recognition

Prevalence

• 0.001%

IgE

• shape

• function

• prevalance

• monomers → 2 antigen binding sites

function: 

• antibody of allergy; reactions against parasitic worm infection

prevalence

• 0.002%

which immunoglobulin classes cross placenta?

IgG only

which immunoglobulin classes fixes complement

IgG and IgM

what does each immunoglobulin classes binds to

• G

  • phagocytes

• A

  • epithelial cells - cuz involve with mucous memory

• M

  • NA

• E

  • NA

• D

  • mast cells and basophils - cuz involve with allergy

average life in serum

• G - longest

  • 23 days

• A

  • 6

• M

  • 5

• E

  • 3

• D

  • 2.5

another name for secondary response of antibody

anamnestic response