a/p final exam part 2

Primary immune response

• first time we are exposed to a specific antigen, B cells are activated and undergo clonal selection

• B cell clones become plasma B cells (make antibodies) and memory B cells (stay in body forever)

• the first exposure you will get sick and experience symptoms of whatever the antigen is.

Secondary immune response

• future exposure to the same antigen, we already have memory B/T cells in the body that mount faster and more efficient attack

• gets rid of antigen quickly so we don’t get sick (no symptoms)

antibody structure/function

• antibody molecules are made by plasma B cells

• they are specific to the antigen in question

• antibodys are protein molecules also called immuglobulins

5 classes of immunoglobulins

• IgG

• IgE

• IgA

• IgD

• IgM

Antibody structure

• Y shaped model

• variable regions: thicker

• constant regions: thinner

Variable regions

• ability to change depending on specific antigen

• the 2 antigen binding sites are at the variable regions because they need to be able to change

• each antibody molecule has 2 antigen binding sites - so it can bind to 2 antigens

4 different ways the antibodies can destroy or incapacitate/inactivate antigens

P: Precipitation

L: lysis

A: agglutination

N: neutralization

P: percipiation

antibody binds to the antigen and its complex is so heavy when binded together that it precipitates (sinks) which incapacitates antigen

L: lysis

• most common way antibodies work

• antibody binds to antigen and activates the complement system which causes lysisor destruction of antigen

A: agglutination

antibody binds to antigens and complexes get stuck together and clump which incapacitates the antigen

N: neutralization:

the antibody binds to the antigen and neutralizes/inactivates it

Active immunity

• being exposed to pathogen/antigen

• going though that whole process, making antibodies and memory B/T cells

Active immunity (naturally acquired)

• when we are exposed to pathogens in our environment we make antibodies and memory cells

• we get sick (get symptoms)

Active immunity (Artificially acquired)

• vaccinations

• when we expose the body to a dead or weakened pathogen (nasal spray), we trick the body into making antibodies (memory B cells)

• we don’t get sick/symptoms

Passive immunity

• protection from pathogens/antigens

• provided by antibodies that are from another source (no memory cells produced)

• temporary - short lived

Passive immunity (naturally acquired)

• mom can pass her antibodies to her fetus across the placenta so the fetus is protected

• mom can pass her antibodies to her baby through breast feeding

Passive immunity (artificially acquired)

antibiotic medications for bacteria/antivenins

cell mediated response:

• activation of T-lymphocytes by antigen presenter cell

• T cells are presented with the antigen by an antigen presenter cell, and this activated the T-cell- T cells undergo clonal selection and makes and army of T cell clones

• 5 different T cells

Cytotoxic (killer) T cells

• have ability to directly attack virus infected/tumor cells

• only T cells that can directly attack/destroy

• destroy cells by releasing cytotoxic chemicals

Helper T cell (CD4)

• managers of immune system

• give immune system momentum (ramp up to full speed)

• recruit/activate other immune cells

• HIV virus attacks these cells

supressor T cells

we need these cells to suppress immune system activity once the pathogen has been destroyed

Delayed hypersensitivity (allergies) T cells

• Help manage delayed hypersensitivity

• allergies to poison ivy/metals/detergents/lotions

Memory T cells

stay in the body forever and mount a stronger, faster, more efficient response to secondary exposure

Antigen presenter cells

• macrophages

• engulf the antigen in question, destroy that antigen, and display the antigen fragments on the surface of the macrophages

• this macrophage is going to entirely engulf that antigen and break it apart into little pieces and display those pieces on its surface

• then presents the antigen to the T cell and activated it