Microbiology Chapter 17

what antigens does the humoral response identify

extra-cellular

what antigens does the cell-mediated response identify 

intra-cellular

what cells are involved in humoral response

b-cells

what cells are involved in cell-mediated response 

t-cells

what type of MHC cell is involved in the humoral response

MHC II

what type of MHC cell is involved in the cell-mediated response 

MHC I

what is an antigen

substance that causes production of antibodies

all antigens have multiple …

epitopes

what is a hapten

antigens too small to provoke immune responses so they attach to a career molecule

hapten molecules and a carrier molecule combine to make a …

hapten-carrier conjugate

explain the structure of a typical antibody molecule

2 heavy chains held together by 2 disulfide bridges with light chains connected by 1 disulfide bridge

the heavy chains are known to be constant regions and activates complement

the light chains are the variable regions

what are the five classes of antibodies

IgG

IgM

IgA

IgD

IgE

which of the 5 antibodies is most abundant

IgG

what is the shape of IgG

monomer

what is 2 known functions of IgG

placental barrier between mother and fetus in immune support

target bacteria and extracellular toxins

what shape is IgM

pentamer

which antibody is first to be made in an immune response

IgM

what is the shape of IgA

dimer

where is IgA found

tears, salvia, mucus

what is the shape of both IgD and IgE

monomers

where are IgD antibodies found

present on surface of B-cells

where are IgE antibodies found

surface on mast cells and basophils

what two responses are IgE antibodies involved in

inflammatory response

anti-parasitic response

what does MHC stand for

major histocompatibility complex (MHC)

what are MHC

genes that encode molecules on the cell surface

where are class I MHC found

membranes of nucleated animal cells

what is the role of class I MHC

identify “self”

where are class II MHC found

on the surface of antigen-presenting cells (APCs), including B cells

what is the 3 step process of activation of B cells to produce antibodies

1. recognition
2. communication
3. action

explain the activation of B cells to produce antibodies

B cell internalizes antigen and expresses on MHC II

T-helper cells recognizes antigen and produce cytokines

cytokines activate b-cells to plasma cells for antibody production

what is a t-dependent antigen

antigen that requires on a t-helper cell to produce antibodies

what is a t-independent antigen

stimulate the B cell without the help of t cells

provoke a weak immune response, usually producing IgM

no memory cells generated

what is the result of antigen-antibody interaction

antigen-antibody complex

what does affinity mean

strength of bond

what does antigen-antibody complex protect

the host by tagging foreign molecules or cells for destruction

what are the 5 results of antigen-antibody complexes

agglutination

opsonization

antibody-dependent cell-mediated cytotoxicity

neutralization

activation of complement system

what is opsonization

coating antigen with antibody enhances phagocytosis

what is the purpose of neutralization

blocks adhesion

what is the result of activation of complement system 

inflammation or cell lysis

pathogens entering the gastrointestinal tract pass through…

microfilm cells (M cells)

where are m cells located over

Peyer’s patches

what is the role of Peyer’s patches

transfer antigens to lymphocytes and antigen-presenting cells (APCs)

what are the two antigen-presenting cells

1. dendritic cells
2. macrophages

what is the role of dendritic cells

engulf and degrade microbes and display them to T cells

where are dendritic cells found

skin, genital tract, lymph nodes, spleen, thymus, mucus membranes, and blood

what is the role of macrophages

activated by cytokines or the ingestion of antigenic material

migrate to the lymph tissue, presenting antigen to T cells

what are the 4 classes of t-helper cells

TH1

TH17

TH2

T reg

what class of cytokine does TH1 cell release

Iγ

what class of cytokine does TH17 cell release 

IL-17

what class of cytokine does TH2 cell release 

IL-4

what is the role of TH1 cells

intracellular cell mediated immunity

what is the role of TH17 cells

extracellular pathogens (humoral)

what is the role of TH2 cells

parasitic immune responses

what is the role of T reg

regulate t-cell activity

what are the 3 stages of cell mediated immunity

1. presentation
2. communication
3. action

explain as a short answer question the stages of cell mediated immunity response

virus infected cell presents antigen on MHC I

TH cells recognizes antigen and releases cytokines

cytokines activate CLT cells which destroy infected cells

what is programmed cell death called

apoptosis

what does apoptosis prevent

spread of infectious viruses into other cells

what two proteins does a CLT cell release

perforin

granzymes

natural killer cells do not need what

stimulation by an antigen / t-helper cells releasing cytokines

what do natural killer cells do

kill virus-infected and tumor cells and attach parasites

what cells don’t express MHC class I self antigens

natural killer cells

when is antibody-dependent cell-mediated cytotoxicity useful

when organisms such as parasites which are too large for ingestion by phagocytic cells must be attacked externally

what is the role of eosinophil

releases cytotoxic cytokines

lytic enzymes and perforin enzymes

what is a a secondary response

occurs after second exposure to an antigen

what is class switching mean in a secondary response

where initial IgM response shifts to IgG, IgE or IgA occurs

what is naturally acquired active immunity

resulting from infection

what is naturally acquired passive immunity

transplacental or via colostrum

what is artificially acquired active immunity

injection of vaccination

what is artificially acquired passive immunity

injection of antibodies