Types-of-Immunity.ppt

Types of immunity

1. TYPES OF IMMUNITY
RAKESH SHARDA

2. Overview of the Immune System
Immune System
Innate
(Nonspecific)
Adaptive
(Specific)
Cellular Components Humoral Components Cellular Components Humoral Components

3. Innateimmunityreferstoanimmediateorearly
antigen-nonspecificdefensemechanismsthatare
presentinahostsincebirthwithoutbeinginduced
andaredesignedtoreactand/oreliminateany
antigen.Thisistheimmunityoneisbornwith
Adaptive(acquired)immunityreferstoantigen-
specificinduceddefensemechanismsthattake
severaldaystodevelopandaredesignedtoreact
and/oreliminateaspecificantigen.Thisisthe
immunityoneacquiresduringlife.
(Adaptive immunity is found exclusively in vertebrates)
Components of the Immune SysteINNATE versus ADAPTIVE IMMUNITY

4. The innate immuneresponses involve:
physical barriers
chemicals -lysozyme, bile salts, sebum, HClacid,
etc
cells that release inflammatory mediators
phagocyticcells
natural killer cells
humoralfactors -complement proteins, acute
phase proteins, and cytokines.
Innate Immunity

5. The Adaptive immune responsesinvolves:
antigen-presenting cells (APCs)such as macrophages and
dendriticcells;
the activation and proliferation ofantigen-specific B-
lymphocytes;
the activation and proliferation ofantigen-specific T-
lymphocytes;
the production ofantibody molecules, cytotoxicT-
lymphocytes (CTLs), and cytokines.
Adaptive Immunity

6. Innate Immunity Adaptive Immunity
Componentsof Innate and Adaptive Immunity
skin, gut Villi, lung cilia,etc
many protein and
non-protein secretions
phagocytes, NK cell
eosinophils, K cells
physical barriers
soluble factors
cells
none
Immunoglobulins
(antibody)
T and B lymphocytes
APCs

7. Skin
GIT
Innate Immunity
Physical barrier
---------------------------------------------------------------------
Chemicalbarrier
---------------------------------------------------------------------
Sweat, Sebum, Tears
(body toxic fluids)
Antigen/ foreign material
+
Cellular barrier
Phagocytosing cells
II Line of defense
Acquired Immunity
I Line of defense
III Line of defense
B T
Antibody
Antibody-mediated ImmunityCell Mediated Immunity
Y
Y
Y
Y Y
Antigen elimination

8. CARDINAL FEATURES OF ADAPTIVE IMMUNE SYSTEM
1.Tolerancetoselfantigens-undernormalconditions,an
immuneresponseto"self"antigens(calledanautoimmune
response)doesnotoccur.
2.Specificity–componentsofadaptiveimmunityreact
specificallywiththeantigenthatinducedtheirformation.
3.Memory-theadaptiveimmunologicalresponse
rememberstheantigenforinvariableperiodoftimeand
uponsubsequentexposuretohomologousantigenthereis
ananamnesticimmuneresponse,i.e.strengthensupon
repeatedexposure

9. Innate Immunity Adaptive Immunity
Characteristics/Differences of
Innate and Adaptive Immunity
No Immunologic
memory
Antigen independent
No time lag
Not antigen specific
Antigen dependent
A lag period
Antigen specific
Development
of memory

11. Classification of Adaptive Immunity
Adaptive
Immune System
Basis of
Effecter molecules
Basis of mode
of development
Humoral
immunity
Cell mediated
Immunity
Active Immunity Passive Immunity

12. Types of Acquired Immunity
(On the basis of effectormolecules)
Humoralimmunity:Humoralorantibodymediated
immunity(AMI)ischaracterizedbytheproductionofantigen-
specificimmunoglobulinmolecules,calledas‘antibodies’,
inducedinresponsetoanantigenandismediatedbyB-
lymphocytes.Antibodiesprimarilydefendagainst
extracellularpathogensandtoxins.Humoralimmunityisso
namedbecauseitinvolvessubstancesfoundinthehumors,
orbodyfluids.
Cell-mediatedimmunity:Cell-mediatedimmunity(CMI)
involvestheactivationofantigen-specificcells,suchas
CTLsandmacrophages,whichdestroysthecellsharboring
antigen.Cellularimmunityprimarilydefendagainst
intracellularpathogens,multicellularparasites,transplanted
tissue,andcancercells.

13. HumoralImmunity Cell mediated Immunity
Characteristics/Differences of
Humoraland Cell mediated Immunity
Effective against
extracellular parasites
B-cell dependent
Effecter molecule -antibodies
T-cell dependent
Effecter –CTL, NK,
macrophages
Effective against
intracellular parasites,
tumor cells, tissue
grafts
MHC restriction: +/-
MHC restriction:+

15. The Interrelation of AMI and CMI
1.ThcellsactivateBcellstoproduceantibodiesagainst
T-dependentantigens(usuallyproteinincomposition).
2.Inantibody-dependentcell-mediatedcytotoxicity
(ADCC),NKcells,macrophages,andotherleukocytes
lyseantibody-coatedcellsthataretoolargetobe
phagocytosed.

16. Types of Acquired Immunity
(On the basis of mode of development)
Activeimmunity,inwhichthehostdevelopsan
adaptiveimmunologicalresponseandproducesthecells
andfactorsresponsiblefortheimmunity.Activeimmunity
canpersistforalongtimeinthehost.
Passiveimmunityisacquisitionbyahostofimmune
factorswhichwereproducedinanotheranimal,i.e.,the
hostreceivespre-formedantibodiesand/orimmuno-
reactivelymphocytes.Passiveimmunityistypically
short-livedandusuallypersistsonlyafewweeksor
months.

17. INFECTION OF “ X”
MILK
(COLOSTRUM)
“ACTIVE IMMUNITY ”
“ PASSIVE
IMMUNITY “
MOTHER
NEWBORN
ANTIBODIES TO “X”
ARE PRODUCED
Resistance

18. Active Immunity Passive Immunity
Characteristics/Differences
of Active and Passive Immunity
Lag period
Titer is time
dependent
Participation of hosts’
immune system
Long lived
Memory
No participation
Short lived
No memory
No lag period
Immediately
high titer

19. Types of
Active & Passive
Immunity
Active immunity Passive immunity
Natural
(e.g. infection)
Artificial
(e.g. vaccination)
Natural
(e.g. maternal Ab)
Artificial
(e.g. Hyper immune
Serum)

21. Advantages Disadvantages
serum sickness
immediate
protection
no long term
protection
graft vs. host
disease (cell
graft only)
risk of hepatitis
and Aids
Advantages and Disadvantages of
Passive Immunization