2. Objectives: Define and ComprehendObjectives: Define and Comprehend
Nonspecific vs. specific immunityNonspecific vs. specific immunity
responsesresponses
Different types of nonspecific responsesDifferent types of nonspecific responses
Humoral vs. cell-mediated immunityHumoral vs. cell-mediated immunity
3. Nonspecific vs. specificNonspecific vs. specific
defensesdefenses
NonspecificNonspecific defenses do not distinguishdefenses do not distinguish
one infectious microbe from anotherone infectious microbe from another
SpecificSpecific defenses recognize and defenddefenses recognize and defend
against invading microbes and canceragainst invading microbes and cancer
cellscells
4. 1 minute brain storm1 minute brain storm
What is an immune system?What is an immune system?
What are the components of an immuneWhat are the components of an immune
system?system?
5. Nonspecific defensesNonspecific defenses
Skin is a barrier that most bacteria andSkin is a barrier that most bacteria and
viruses can’t penetrateviruses can’t penetrate
Acids secreted by skin prohibit growth ofAcids secreted by skin prohibit growth of
many microbesmany microbes
Sweat, saliva, and tears contain enzymes thatSweat, saliva, and tears contain enzymes that
attack bacterial cell wallsattack bacterial cell walls
Mucus produced in digestive andMucus produced in digestive and
respiratory systems also protects againstrespiratory systems also protects against
microbesmicrobes
6. Nonspecific defensesNonspecific defenses
Microbes that penetrate skin, digestive, orMicrobes that penetrate skin, digestive, or
respiratory systems face neutrophils andrespiratory systems face neutrophils and
monocytesmonocytes
macrophages that “eat” bacteria and virusesmacrophages that “eat” bacteria and viruses
Interferons and complement proteinsInterferons and complement proteins
attack microbes either directly or indirectlyattack microbes either directly or indirectly
by impeding their reproductionby impeding their reproduction
7. Nonspecific defensesNonspecific defenses
Interferons are produced by infected cellsInterferons are produced by infected cells
Diffuse to healthy cells where they cause theDiffuse to healthy cells where they cause the
cell to inhibit viral productioncell to inhibit viral production
Complement proteins are activated byComplement proteins are activated by
microbes or immune systemmicrobes or immune system
Coat infected cells –easier to eatCoat infected cells –easier to eat
Can amplify inflammatory responseCan amplify inflammatory response
9. Nonspecific defenses: inflammatoryNonspecific defenses: inflammatory
responseresponse
Redness, heat, and swelling caused byRedness, heat, and swelling caused by
Increase in blood flow, fluid, and cellsIncrease in blood flow, fluid, and cells
Inflammatory response disinfects andInflammatory response disinfects and
cleans injured tissuescleans injured tissues
Pus = dead white cells and fluidPus = dead white cells and fluid
Systemic response is widespreadSystemic response is widespread
Toxins or microorganisms released inToxins or microorganisms released in
bloodstreambloodstream
Circulates through bodyCirculates through body
10. Nonspecific defenses: inflammatoryNonspecific defenses: inflammatory
responseresponse
Systemic response cont’d.Systemic response cont’d.
Inflammatory weapons: increase white bloodInflammatory weapons: increase white blood
cells, fevercells, fever
Low-grade fever can stimulate phagocytosis andLow-grade fever can stimulate phagocytosis and
inhibit growth of many microorganismsinhibit growth of many microorganisms
12. Lymphatic systemLymphatic system
Involved in both specific and nonspecificInvolved in both specific and nonspecific
responsesresponses
Lymphatic system defenses occur in lymphLymphatic system defenses occur in lymph
nodes and lymphatic system organsnodes and lymphatic system organs
Packed with lymphocytes and macrophagesPacked with lymphocytes and macrophages
Lymph carries microbes from infection sites and someLymph carries microbes from infection sites and some
cancer cellscancer cells
In the lymphatic organs, macrophages may “eat” theIn the lymphatic organs, macrophages may “eat” the
invaders (nonspecific)invaders (nonspecific)
Lymphocytes can be involved in specific immuneLymphocytes can be involved in specific immune
responseresponse
13. Lymphatic systemLymphatic system
Why do your lymph nodes swell when youWhy do your lymph nodes swell when you
are fighting certain kinds of infections?are fighting certain kinds of infections?
Production of lymphocytes in nodesProduction of lymphocytes in nodes
14. Specific immunitySpecific immunity
Often more effective than nonspecific responseOften more effective than nonspecific response
It also amplifies nonspecific responseIt also amplifies nonspecific response
Specific response begins due to presence of anSpecific response begins due to presence of an
antigenantigen
Can either increase number of cells that attackCan either increase number of cells that attack
invader directly ORinvader directly OR
Produce antibodiesProduce antibodies
Immune system “remembers” antigens it hasImmune system “remembers” antigens it has
previously encounteredpreviously encountered
Responds immediately and vigorouslyResponds immediately and vigorously
Is adaptiveIs adaptive
16. Objectives: Define & ComprehendObjectives: Define & Comprehend
Role of clonal selection in immunity responseRole of clonal selection in immunity response
Primary vs. secondary responsePrimary vs. secondary response
AntibodiesAntibodies
T cellsT cells
Autoimmune vs. immunodeficiency diseasesAutoimmune vs. immunodeficiency diseases
AllergiesAllergies
HIV/AIDSHIV/AIDS
18. Specific Immunity: LymphocytesSpecific Immunity: Lymphocytes
Humoral systemHumoral system defends againstdefends against
bacteria and viruses present in body fluidsbacteria and viruses present in body fluids
Fluids: blood, lymph, and interstitial fluidFluids: blood, lymph, and interstitial fluid
Antibodies,Antibodies, secreted by B cellssecreted by B cells and dissolvedand dissolved
in the blood, are carried in lymph and blood toin the blood, are carried in lymph and blood to
sites of infectionssites of infections
Cell-mediated immunityCell-mediated immunity
T-cells circulate in blood and lymphT-cells circulate in blood and lymph
Attack body cellsAttack body cells that have been infectedthat have been infected
19. Specific Immunity: LymphocytesSpecific Immunity: Lymphocytes
For BOTH humoral and cell-mediatedFor BOTH humoral and cell-mediated
immunityimmunity
B & T cells have antigen receptorsB & T cells have antigen receptors
(antibodies) that protrude from cell surface(antibodies) that protrude from cell surface
specific for one type of antigen**specific for one type of antigen**
Each person has between 100 million to 100Each person has between 100 million to 100
billion different kinds of B & T cells!billion different kinds of B & T cells!
20. AntigensAntigens
Most antigens are molecules that areMost antigens are molecules that are
present on viral surfaces or foreign cellspresent on viral surfaces or foreign cells
B cells respond to free antigens in bodyB cells respond to free antigens in body
fluidfluid
Different antibodies can bind to the sameDifferent antibodies can bind to the same
antigenantigen
24. QuestionQuestion
Why are “childhood” diseases referred toWhy are “childhood” diseases referred to
as such?as such?
First exposure occurs during childhood, whichFirst exposure occurs during childhood, which
then confers immunity during remaining yearsthen confers immunity during remaining years
of the individual’s lifeof the individual’s life
25. How do antibodies block invaders?How do antibodies block invaders?
Antibodies bond to antigen molecules,Antibodies bond to antigen molecules,
which marks them and results in either:which marks them and results in either:
An increase in the possibility of phagocytosisAn increase in the possibility of phagocytosis
Activation of complement proteins that canActivation of complement proteins that can
cause the invader’s cell to rupture***cause the invader’s cell to rupture***
D:ImageLibrary16-2624-TheImmuneSystem24-11-AntibodiesAnim.movD:ImageLibrary16-2624-TheImmuneSystem24-11-AntibodiesAnim.mov
26. Role of T cells in ImmunityRole of T cells in Immunity
T cells battle pathogens that haveT cells battle pathogens that have alreadyalready
entered body cellsentered body cells
Respond to antigens that have bonded toRespond to antigens that have bonded to
body cell surfacesbody cell surfaces
Mount cell-mediated defense and aid humoralMount cell-mediated defense and aid humoral
immunityimmunity
27. T cellsT cells
Cytotoxic T cellsCytotoxic T cells
Only T cells that kill other cellsOnly T cells that kill other cells
Synthesize a protein that ruptures infected cellSynthesize a protein that ruptures infected cell
Helper T cellsHelper T cells
Secrete stimulatory proteins that helpSecrete stimulatory proteins that help
Promote production of more helper T cells andPromote production of more helper T cells and
memory cellsmemory cells
Activate cytotoxic T cellsActivate cytotoxic T cells
Stimulate B cells to produce antibodiesStimulate B cells to produce antibodies