Antigens (foreign cells and molecules)

~ viruses ~ bacteria ~ foreign tissue ~ molecules

Some cause disease

3 Lines of defense against disease1. Skin and mucous membranes (non- specific)

2. Inflammatory response (non-specific)

3. Immune Response (specific)

Exam

Skin cells with bacteria (green rods)

hair

3 Lines of defense against antigens1. Skin and mucous membranes (non-specific)

2. Inflammatory response (non-specific)

3. Immune Response (specific)

http://www.beyondbooks.com/lif71/images/00016305.jpg

Neutrophil, a type of lymphocyte which scavenges for antigens

http://darwin.bio.uci.edu/~cchughes/Media/VessSEM.jpg

Lymphocytes on wall of blood vessel

Inflammatory Response

Skin cells

Bacteria and other antigens

Histamine released by damaged cells

Histamine causes blood vessels to leak

Neutrophils leak out and eat antigens

Capillary with Neutrophils and other blood cells

Same process in allergic reactions to pollen, chocolate, etc.

Antigens

Cut in skin

Histamine causes capillaries to open up (distended)

White blood cells go to injury site.

Neutrophils (WBC) eat bacteria by phagocytosis

Inflammatory Response

Damaged cells releases histamine

Neutrophil or macrophage eating bacteria

3 Lines of defense against antigens1. Skin and mucous membranes (non-specific)

2. Inflammatory response (non-specific)

3. Immune Response (specific)

Unspecialized stem cell

Thymus Gland

macrophageT-cell

Bone marrowImmune Response –

specific antigen

Bone

B-cell

EXAM

B cell

Macrophage

plasmacyte

Killer T cell

Suppressor T cell

Helper T cell

Complex formed = antigen + macrophage + B cell + Helper T cell

Antigen

EXAM 30,000 antibodies seconds / cell

Antigen – antibody complex reduces capacity of antigen to cause disease

Rhinovirus with

antigenic sites

brightly colored

Antibodies attached to the antigenic sites of the Rhinovirus

Specific virus

Specific antibody against specific virus

Specific antibody-antigen (virus) complex – neutralizes virus

Pre-existing in the human body is at least one specific pre-antibody producing cell (B-Cell) for every possible antigen – literally millions.

How?How can 35000

genes make millions of protein

antibodies?

One gene = one protein

Humans and other mammals can make a specific antibody for every antigen to which it is exposed

1000 antigens = 1000 antibodies

1,000,000 antigens = 1,000,000 antibodies

1,000,000,000 antigens = 1,000,000,000 antibodies

1 gene = 1 protein (antibody)

1,000,000 antibodies = 1,000,000 genes

Humans have about 35,000 genes

How do we make so many antibodies or proteins?

Makes protein or antibody X

New arrangement makes protein or antibody Y

DNA

DNA

Barbara McClintock proposes (1948) that DNA shuffling makes

new genes

EXAM

Lise Meitner

Otto Hahn gets Nobel Prize for

discovery of nuclear fission

Rosalind FranklinWatson, Crick, Wilkins get Nobel

Prize for DNA

Barbara McClintockBarbara gets Nobel Prize (1983) for gene shuffling……………. and a postage stamp

memory B cell X for Virus X

B cell X is cloned

B cells for Viruses A, B, C, D, E……………X, and billions more antigens

Virus X + B cell for Virus X combine

Virus X

Clonal Selection

theory

B-cell for Virus X

Plasmacyte (formed from B-cell X) makes Antibody X specific

for virus X

Antibody X neutralizes Virus X

Clonal Selection Theory

Pre-existing specific B-cells for all antigens

Specific antigen X

Cloning of specific B-cell for

antigen XMemory B-cells specific

for antigen X

Cloned plasmacytes make only antibodies

for antigen XAntigen X + Antibody X complex

0 7 14

First exposure

Second exposure

Days

Amount of

antibody

0 7 14

EXAM

Day 1No antibody production

Day 2

Day 3

Day 4

Day 5

B cell meets antigen

Ribosomes start to appear

Endoplasmic reticulum appears

More ribosomes and E.R.

Antibodies produced

B cell before contact with antigen – little or no rough endoplasmic

reticulum or ribosomes

B cell 5 days after contact with antigen – extensive Rough Endoplasmic Reticulum

and ribosomes

T cell killing cancer cell (yellow)

Notice all that’s left is cytoskeleton (yellow)

Macrophage eating cancer cell (yellow)

Why is cancer a disease of aging?

1 10 20 30 40 50 60 70 80

Immune system

Incidence of cancer

Relative activity

Human age

Autoimmune disease – immune system attacks self = rheumatoid arthritis = immune system attacks joints

EXAM

Multiple sclerosis = Autoimmune disease = T cells attack nerve cells

Immune cells release histamine when they encounter allergen (antigen such as pollen, chocolate, peanuts, etc.)

Immune cell

allergen

Histamine causes sneezing, runny nose, swollen eyes, swollen throat, etc.

Allergy = overreaction to antigen