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