5. A germ is still a germ….A germ is still a germ….
1.1. PathogenPathogen=agent that causes disease=agent that causes disease
22. Antigen. Antigen= foreign particle that triggers an= foreign particle that triggers an
immune responseimmune response
- often they are proteins on- often they are proteins on
the surface of viruses andthe surface of viruses and
bacteriabacteria
6. Your Body’s Defenses AgainstYour Body’s Defenses Against
DiseaseDisease
Nonspecific Defenses: Attack allNonspecific Defenses: Attack all
pathogens and antigens the same waypathogens and antigens the same way
Specific Defenses: Immune Response –Specific Defenses: Immune Response –
Attack pathogens that get past theAttack pathogens that get past the
nonspecific defensesnonspecific defenses
7. Nonspecific DefensesNonspecific Defenses
This means that the identity of theThis means that the identity of the
pathogen/antigen ispathogen/antigen is not importantnot important..
The response is the same if aThe response is the same if a
bacteria, virus, splinter or bulletbacteria, virus, splinter or bullet
invades the body.invades the body.
8. Nonspecific DefensesNonspecific Defenses
First Line DefensesFirst Line Defenses
Skin: Forms a physical barrier to pathogensSkin: Forms a physical barrier to pathogens
-oils and sweat make skin acidic – inhibits-oils and sweat make skin acidic – inhibits
the growth of pathogensthe growth of pathogens
-lysozyme-enzyme found in sweat and tears-lysozyme-enzyme found in sweat and tears
digests bacterial cell wallsdigests bacterial cell walls
Mucus Membranes-layers of tissue whichMucus Membranes-layers of tissue which
secrete mucussecrete mucus
- found in body openings and the respiratory- found in body openings and the respiratory
systemsystem
- mucus traps pathogens- mucus traps pathogens
9. Nonspecific DefensesNonspecific Defenses
Second Line DefensesSecond Line Defenses Inflammatory ResponseInflammatory Response
Damaged cells release histamines – chemical cry for helpDamaged cells release histamines – chemical cry for help
- histamines cause blood vessels to dilate (open) bringing- histamines cause blood vessels to dilate (open) bringing
blood to the area.blood to the area.
- the dilated blood vessels become leaky releasing fluid and- the dilated blood vessels become leaky releasing fluid and
white blood cells in the infected areawhite blood cells in the infected area
- causes swelling and redness in the damaged area- causes swelling and redness in the damaged area
- pus – fluid and dead cells forms- pus – fluid and dead cells forms
White Blood cellsWhite Blood cells
- Macrophages –- Macrophages – “Big Eaters” engulf and kill pathogens“Big Eaters” engulf and kill pathogens
- Neutrophils-- Neutrophils-engulf bactera and release chemicals thatengulf bactera and release chemicals that
kill the bacteria and themselves.kill the bacteria and themselves.
-- Natural Killer Cells –Natural Killer Cells – recognize and kill virus infectedrecognize and kill virus infected
11. Textbook page 925Textbook page 925
Histamines are released Blood vessels dilateHistamines are released Blood vessels dilate
and leakand leak
13. Nonspecific DefensesNonspecific Defenses
Second Line Defenses (continued)Second Line Defenses (continued)
Temperature Response -Temperature Response - Fever –Fever –
-Body temp increases in response to infection-Body temp increases in response to infection
-pathogenic bacteria don’t grow well at higher temp-pathogenic bacteria don’t grow well at higher temp
ProteinsProteins
-- Complement Proteins:Complement Proteins: kill pathogens by punching akill pathogens by punching a
hole in the cell membranehole in the cell membrane
- Intrerferon:- Intrerferon: a protein released by cells infected by virusesa protein released by cells infected by viruses
-causes nearby cells to release an enzyme preventing the virus-causes nearby cells to release an enzyme preventing the virus
from reproducingfrom reproducing
16. Specific DefensesSpecific Defenses
Third Line of DefenseThird Line of Defense
Specific DefensesSpecific Defenses
- identity of pathogen/- identity of pathogen/
antigen must be knownantigen must be known
- the specific immune- the specific immune
response is tailored toresponse is tailored to
the specific pathogenthe specific pathogen
17. Specific DefensesSpecific Defenses
Macrophage Links Nonspecific to SpecificMacrophage Links Nonspecific to Specific
When a macrophage engulfs a pathogen, itWhen a macrophage engulfs a pathogen, it
displays the viral antigen on its surfacedisplays the viral antigen on its surface
The antigen is joined to a MHC
(Major Histocompatibility Complex)
The MHC is a protein on the surface of
all vertebrate cells
The anitgen must be bound to the MHC for the Helper T Cell to recognize it
18. Specific DefensesSpecific Defenses
Helper T CellsHelper T Cells
Receptor proteins on helper T cells (TReceptor proteins on helper T cells (THH) bind to) bind to
viral antigens displayed on the macrophageviral antigens displayed on the macrophage
causes macrophage tocauses macrophage to
release Interleukin1release Interleukin1
Interleukin1 activatesInterleukin1 activates
the helper T cells (Tthe helper T cells (THH))
19. Specific DefensesSpecific Defenses
Helper T CellsHelper T Cells continuedcontinued
Activated helper T cells (TActivated helper T cells (THH) release proteins called) release proteins called
cytokines which activate cytotoxic T cells (Tcytokines which activate cytotoxic T cells (TCC) and B cells) and B cells
The activated (TThe activated (TCC) and B cells begin to divide) and B cells begin to divide
20. Specific DefensesSpecific Defenses
Cell Mediated ResponseCell Mediated Response
Receptor proteins on theReceptor proteins on the
cytotoxic T cells (Tcytotoxic T cells (TCC) bind to) bind to
viral antigens displayed byviral antigens displayed by
infected cellsinfected cells
Cytotoxic T cells (TCytotoxic T cells (TCC) punch a) punch a
hole in the cell’s membranehole in the cell’s membrane
Your body produces manyYour body produces many
cytotoxic T cells (Tcytotoxic T cells (TCC))
21. Specific DefensesSpecific Defenses
Antibody Mediated ResponseAntibody Mediated Response
B cells divide and develop intoB cells divide and develop into
plasma cellsplasma cells
Plasma cells release large numbersPlasma cells release large numbers
of antibodiesof antibodies
AntibodiesAntibodies bind to antigens onbind to antigens on
pathogenspathogens
Antibodies cause pathogens to clumpAntibodies cause pathogens to clump
holding them until macrophagesholding them until macrophages
can engulf themcan engulf them
Antibodies are specific to a particular pathogen-yourAntibodies are specific to a particular pathogen-your
body produces the antibodies in response to infectionbody produces the antibodies in response to infection
23. The Specific Defense has twoThe Specific Defense has two
phasesphases
Primary ImmunePrimary Immune
Response:Response:
--Occurs when the bodyOccurs when the body
has never encountered ahas never encountered a
pathogen /antigen before.pathogen /antigen before.
-Immune system goes-Immune system goes
through all of the stepsthrough all of the steps
-After the threat has-After the threat has
passed,passed, MEMORY CellsMEMORY Cells
are made.are made.
SecondarySecondary
ImmuneImmune
Response:Response:
The next time theThe next time the
pathogeninvadespathogeninvades
MEMORY CellsMEMORY Cells identifyidentify
the invader and athe invader and a
massive volume ofmassive volume of
antibodies are released,antibodies are released,
destroying the invaderdestroying the invader
before you feel ill.before you feel ill.
You are immune!You are immune!
25. How do vaccines work?How do vaccines work?
VaccinesVaccines are made up of weakened viralare made up of weakened viral
particles.particles.
The weakened particles stimulate a smallThe weakened particles stimulate a small
number of antibodies and memory cells tonumber of antibodies and memory cells to
be produced.be produced. Primary Immune ResponsePrimary Immune Response
When a the pathogen attacks, theWhen a the pathogen attacks, the
antibody production is larger.antibody production is larger.
Secondary Immune ResponseSecondary Immune Response
27. VocabularyVocabulary
Pathogen B cells T cellsPathogen B cells T cells
MacrophagesMacrophages
Nonspecific DefenseNonspecific Defense
VaccinesVaccines
Primary Immune ResponsePrimary Immune Response
Secondary Immune ResponseSecondary Immune Response
Editor's Notes
Histamines are released which cause the blood vessels to dilate allowing more blood to reach the infection.
Polio – virtually eradicated from western hemisphere. Horrible from in US from 1900 -1955 when the Salk vaccine was widely made available The height of the epidemic was 1952 60,000 cases 3000 fatalities 5% fatality rate. Typically transmitted in poop (not washing hands or drinking contaminated water)