Download Chapter I Overview of Immunology

Chapter 2
Concept, Functions and Types
of Immunity
Chapter 2
Concept, Functions and Types of Immunity
Introduction
Concept and functions of Immunity
Types of Immunity
Part I Concept and functions
of Immunity
I Concept of Immunity
1)Tranditional concept----Immunity refers to
protection against infectious diseases.
2)Modern concept---- Immunity is a function of
which an individual recognizes and excludes
antigenic foreign substances. It is normally
beneficial,but sometimes,it is injurious.
II Concept of Immunology
1) Tranditional concept----anti-infection immunity
to
different
types
of
pathogenic
microorganisms.
2)
Modern
concept----Immunology
is
an
independent
subject
about
composition,functions of immune system;
mechanism of immune response and the disease
associated with immunity.
III Functions of Immunity
Immune defense
Immune homeostasis
Immune surveillance
Functions and Manifestation of Immunity
Functions
Normal Manifestation
Abnormal Manifestation
Immune
Hypersensitivity
Defense
Immunodeficiency
Immune
Homeostasis
Immune
Surveillance
infection
Eliminate injured and senile cells
Tolerate to self components
Anti-infection
immune dismodulation
Autoimmune disease
destroy transformed cells
(anti-tumor )
Prevent from persistent infection
Tumor or
Persistent virus
Part II Types of Immunity
I. Innate Immunity
(or native immunity/ non-specific immunity
/congenital immunity)
II. Adaptive Immunity
(or acquired immunity/specific immunity)
I. Innate immunity
( natural immunity/ non-specific immunity )
Innate immunity:
Protection against infection that relies on
mechanisms that exist before infection,are
capable of a rapid response to microbes,and
react in essentially the same way to repeated
infections.
 Exists at birth
 Be the first line of defense against infection
Innate immunity
1. Characteristics
 Exists naturally
 Non–specific
 No immune memory (innate immunity can’t
be enhanced by the second stimulation of
the same antigen)
Immune memory: Exposure of the immune
system to a foreign antigen enhances its
ability to respond again to that antigen.
 Hereditable
 No racial difference
2. Composition
(1) Barriers
 Physical barrier : skin and mucosa
 Chemical barrier: antimicrobial substances in
secretion of skin and mucosa
 Biotic barrier: normal flora existing on the surface
of skin and mucosa
 Anatomic barrier
. blood- brain barrier
. blood- placental barrier
. blood- tymus barrier
(2) Humoral factors
 Complement
 Lysozyme
 Interferons(IFN)
 C-reactive protein
(3)Cells participating in innate immunity
 Phagocyte: endocytosis and phagocytosis
mononuclear phagocytes
----Monocytes,Macrophages (M Φ)----PRR
Neutrophils
 Nature killer cells (NK)—KAR/KIR,IgG
receptor
 Dentritic cells(DC)
 γδ T cells
 B1 cells
 Other cells participating in innate immunity
Fc
Macrophages
NK cells
Neutrophils
Macrophages
Macrophages excluding the
pathogen
II.Adaptive immunity
( acquired immunity/specific immunity)
Adaptive immunity:
The form of immunity that is mediated by
T or B lymphocytes and stimulated by
exposure to infectious agents.
 Take effects after innate immune response
 Be the second line of defense against
infection
1.Characteristics
 Specificity
 Acquired (set up after birth )
 Immune memory
(Adaptive immunity can be enhanced by the
second stimulation of the same antigen)
 Transferable
 Self-limitation
2.Composition
T cell : Cell-mediated immunity (CMI)
B cell : Humoral immunity(HI) or
antibody-mediated immunity
3.The process of immune
response
in adaptive immunity
Recognition of antigens
Activation,proliferation and
differenciation of T or B lymphocytes
Effector phase of immune response
----Elimination of antigens
Comparison of Adaptive and Innate
Immunity
Innate immunity
Adaptive immunity
Characteristics Exists naturally
Acquired by antigen stimulation after birth
Responds rapidly in the early
develops slowly
stage of infection
No antigen specificity
Has antigen specificity
No immune memory
Has immune memory
Participates in natural defence
Participates in specific immune response
Cells
Neutrophil,Phagocytes,NK cell et al.
T cell, B cell, APC
Molecules Complement.lysozyme,cytokines et al
Antibody,cytokines