B CellsB CellsAdaptive or Specific Immune Adaptive or Specific Immune

ResponseResponse

Lymphatic systemLymphatic system Looks similar to Looks similar to

circulatory systemcirculatory system Primary lymphoid Primary lymphoid

organs: bone marrow organs: bone marrow and thymusand thymus– Lymphocytes develop Lymphocytes develop

and matureand mature– Circulating Circulating

lymphocytes parole for lymphocytes parole for foreign cells or foreign cells or substances “substances “immune immune surveillance”surveillance”

http://a248.e.akamai.net/7/248/430/20020531071023/www.merck.com/pubs/mmanual_home/illus/i167_1.gif

Lymphocytes develop from stem cells in bone marrow

http://www.acm.uiuc.edu/sigbio/project/updated-lymphatic/lymph_cell.gif

Lymph NodesLymph Nodes Secondary Secondary

lymphoid organslymphoid organs– Junctions where Junctions where

circulating circulating lymphocytes lie and lymphocytes lie and wait for pathogenswait for pathogens

Infection causes Infection causes lymphocytes to lymphocytes to multiplymultiply– Lymph nodes swellLymph nodes swell

www.drpaul.com/illnesses/ enlarged.html

Bone MarrowBone Marrow hemopoietic stem cellshemopoietic stem cells

– Form of adult stem cellsForm of adult stem cells– Do not have a specific Do not have a specific

function yetfunction yet– Can develop into any blood Can develop into any blood

cellcell Red blood cells, platelets, Red blood cells, platelets,

T-cells, macrophages, B T-cells, macrophages, B cellscells

Today, we’re learning about B Today, we’re learning about B cellscells– Humorial mediated immunityHumorial mediated immunity

Take care of free antigens Take care of free antigens floating in bloodfloating in blood

www.cancerbacup.org.uk/ info/myelo/myelo-2.htm

B-cells: One type of B-cells: One type of lymphocytelymphocyte

2 main lymphocytes2 main lymphocytes– B cellB cell

Matures in Matures in bonebone marrow marrow– T cellT cell

Primary rolePrimary role: produce : produce antibodies to a specific antibodies to a specific antigenantigen– Each B cell has one Each B cell has one

certain antibodycertain antibody– Each cell covered with Each cell covered with

thousands of these thousands of these identical antibodiesidentical antibodies

Antibodies(Ab)Antibodies(Ab) A family of proteins encoded A family of proteins encoded

by Immunoglobin geneby Immunoglobin gene Constant region puts Constant region puts

Ab(antibodies) in one of five Ab(antibodies) in one of five classes of Abclasses of Ab– 1. IgM1. IgM– 2. IgA2. IgA

Major in intestinal and Major in intestinal and respiratory liningrespiratory lining

– 3. IgD3. IgD– 4. IgG4. IgG

Major response against Major response against bacteriabacteria

– 5. IgE5. IgE Allergic responsesAllergic responses

http://www.biology.arizona.edu/immunology/tutorials/antibody/graphics/antibody.gif

AntibodiesAntibodies Defense against Defense against

antigensantigens Immune system Immune system

related proteins called related proteins called immunoglobinsimmunoglobins

Amino acids vary in Amino acids vary in variable regionvariable region at at antigen binding siteantigen binding site

Many different Many different variable regionsvariable regions

http://www.biology.arizona.edu/immunology/tutorials/antibody/graphics/antibody.gif

B cells recognize an antigenB cells recognize an antigen B cells antibodies B cells antibodies

act as receptors on act as receptors on cell surfacecell surface

Recognize antigenRecognize antigen Signal B cell to Signal B cell to

start dividingstart dividing ProliferationProliferation=divid=divid

e and multiply e and multiply rapidlyrapidly

http://www.griffindesign.com/media/illust/titan/monochromal_antibody.jpg

http://www.medhelp.org/NIHlib/GF-739-b_cell.gif

B cells proliferateB cells proliferate Activated B cells Activated B cells

becomebecome 1. Plasma cells1. Plasma cells

– Live for a few daysLive for a few days– Tiny factories that Tiny factories that

produce thousands of produce thousands of antibodies(Ab)antibodies(Ab)

– Ab now are free to float Ab now are free to float through bodythrough body

2. Memory cells2. Memory cells– Live for a lifetimeLive for a lifetime– Body is ready for next Body is ready for next

time you encounter time you encounter same pathogensame pathogen

http://www.medhelp.org/NIHlib/GF-739-b_cell.gif

AntibodiesAntibodies 1. Neutralize antigen1. Neutralize antigen

– Coats pathogenCoats pathogen– Prevents it from Prevents it from

causing diseasecausing disease– Causes it to clotCauses it to clot

2. Antibody 2. Antibody promotes promotes phagocytosisphagocytosis– Mark them for Mark them for

destructiondestruction

Overview of B cell Overview of B cell ActivationActivation

Macrophage “eating Macrophage “eating vaccuum” eats vaccuum” eats bacteriabacteria

B cell sees antigenB cell sees antigen Becomes Becomes plasma cellplasma cell

to make Abto make Ab– Ab latches onto free Ab latches onto free

bacteriabacteria B cell also becomes B cell also becomes

memory cellmemory cell for next for next time(not shown)time(not shown)

http://www.medimagery.com/physiology/B-cell.jpg

Blood TypingBlood Typing Blood type depends on Blood type depends on

presence or absence of presence or absence of antigens on red blood cellsantigens on red blood cells

Most familiar is A, B and OMost familiar is A, B and O– Blood type A has A antigensBlood type A has A antigens– Blood type B has B antigensBlood type B has B antigens– Type AB has both A and BType AB has both A and B antigensantigens– Type O has neitherType O has neither

http://gslc.genetics.utah.edu/units/basics/blood/images/ABObloodsystem.gif

Rh factorsRh factors Rh factor: another blood Rh factor: another blood

proteinprotein Found when we were Found when we were

studying rhesus monkeysstudying rhesus monkeys Either you have it or you Either you have it or you

don’tdon’t B- means B with no RhB- means B with no Rh AB + means AB with RH AB + means AB with RH

presentpresenthttp://www.abc.net.au/science/news/img/tetra.jpg

Rh SicknessRh Sickness Important for pregnant mothersImportant for pregnant mothers to know Rh factors of babyto know Rh factors of baby Baby may inherit Rh from fatherBaby may inherit Rh from father

Ex. Rh- mom may have Rh+ babyEx. Rh- mom may have Rh+ baby– If fetal blood gets into mother’s bloodstream If fetal blood gets into mother’s bloodstream

during laborduring labor– Mom makes antibodies against Rh proteinMom makes antibodies against Rh protein

Attacks baby blood causing anemia, brain Attacks baby blood causing anemia, brain damage and even deathdamage and even death

– Baby may need blood transfusionBaby may need blood transfusion Treatment: inect RhIg and/or induce Treatment: inect RhIg and/or induce

laborlaborhttp://www.rit.ac.th/homepage-sc/charud/bioweek/pic1/pregnancy.gif

Wrong Blood TypeWrong Blood Type Body will produce antibodies to proteins Body will produce antibodies to proteins

you don’t haveyou don’t have– Antibodies coat foreign blood cellsAntibodies coat foreign blood cells– Cause it to clot togetherCause it to clot together– May block blood vessels and cause May block blood vessels and cause

serious health risksserious health risks Jessica Jessica SantillanSantillan

– @Duke University@Duke University– 17 years old girl17 years old girl– O + blood typeO + blood type– Received type A organs during a Received type A organs during a

transplanttransplanthttp://www.cnn.com/2003/HEALTH/02/22/transplant.error/

http://www.lifesci.utexas.edu/faculty/sjasper/images/john24.13.jpg