This document summarizes the different types of immunity. There are two main types: innate (non-specific) immunity, which is the body's first line of defense and does not depend on previous exposure; and acquired (adaptive/specific) immunity, which develops over time after exposure and retains memory to mount a stronger response next time. Innate immunity includes physical barriers and cellular barriers like phagocytes and cytokines. Acquired immunity consists of antibody-mediated (humoral) immunity and cell-mediated immunity, and can be actively or passively acquired through natural infection or vaccination.

1. Types of immunity
 Dr. sunita

2. Immunity
 Immunity can be defined as the way in
which the body can protect itself from
invasion by pathogenic microorganism and
provide a defense against their harmful
effect.

3.  The physiologic function of the immune
system is to conform protection against
infectious microbes and non-infectious
macromolecules.

4. TYPES OF IMMUNITY
 There are two types of immunity.
 Innate or Non-specific or Natural or
Native immunity and
 Adaptive or acquired or specific
immunity.
 This can be further divided based on
cellular and humoral responses. Both
could be either natural or artificial.

6. INNATE IMMUNITY
 This is also known as Non-specific or Non-
adaptive immunity. Innate immunity is the first
line of defense against infectious organisms and
do not depend on previous exposure i.e. the
immunity existed before encountering the
microbes.

7.  Non specific host responses provide an effective
barrier that prevent the microorganisms from
penetrating, inhibit or destroy the invader if it
gains access to the tissues, and eliminate or
neutralize any toxic substance elaborated by
infectious agent.

8.  Several mechanisms are available in the
immunocompetent host. These include
physical or mechanical barrier, biochemical
factors, cellular mechanism, role of normal
flora & inflammatory reactions.

9. Components
 Innate immunity operates through various
components. It includes mainly physiological and
chemical barriers, and cellular barriers.

10. Components of innate immunity
are:
 Physical and chemical barriers or external
barriers - e.g. skin , epithelial cells, tears etc.
 Biological Barriers - Phagocytic cells
(neutrophils, macrophages) and NK (natural
killer) cells.

11.  Blood proteins - complement and other
mediators of inflammation (Humoral factors).
 Cellular factors - cytokines
 Genetic factors

12. ACQUIRED IMMUNITY :
 Also known as specific immune response. The
more effective will be its different agents the
micro organisms.

13.  The acquired immune response also retain the
memory of previous exposer to the antigen so
that next time it encounter the same antigen
more stronger will be response.
 The acquired immune response takes several
days to the develop that is it develops rather
slowly but once develops the immune response
is incredibly effective.

14.  The adaptive immunity is a defense system that
protects the body against pathogenic
microorganisms and other type of disease such
as cancer. It allows the body to recognize,
remember, and respond to a specific stimulus, an
antigen. Specific immunity can result in the
elimination of microorganisms and in the
recovery from disease, and it frequently leaves
the host with specific immunologic memory.

15.  This condition of memory or recall, acquired
resistance, allows the host to respond more
effectively if reinfection with the same
microorganism occurs. As a consequence of
such acquired immunity, we usually suffer from
many diseases only once, for example measles.
Specific immunity can be active or passive, and
each of these types can in turn be naturally or
artificially acquired.

16. The acquired immune response
consist of two main types-
 1). Antibody mediated immune response
 2). Cell mediated immune response

17. 1). Antibody mediated immune
response
 The branch of the acquire immunity system is
derived agents extracellular /exogenous antigen.
Protein known as antibody promoter the
distraction of these invader.
 This type of immunity systems more time called
as HUMORAL IMMUNITY response. Since the
antibody are found in body fluid.

18.  If an exogenous antigen gain access in our body,
antigen will be produced that can bind to that
antigen and ensure its distraction.
 During first or primary response the amount of
antibody forms is relatively small as compare to
secondary immune response.

19. 2). Cell mediated immune
response:
 The many micro organism live inside the host
cell where is possible for humoral antibody rich
them obligate intracellular parasites such as
viruses, have to replicate inside.

20.  The cell medial immune response also retains
the memory of previous exposer so that next
time when the same antigen enter in the body a
more effective and equally the immune response
is mounted.

21. Passive immunity
It is an immunity in which antibodies produced
elsewhere are given to the individual. They are
divided into two:
I. Naturally acquired passive immunity:
refers to antibodies
transferred from mother to fetus across the
placenta and to the newborn in colostrums and
breast milk during the first few months of life.

22. ii. Artificially acquired passive immunity:
is introduction
of antibodies that are formed by an animal or a
human to an individual to prevent or treat
infection.

23. Active immunity
It is a product of the individual’s own immune
system in response to a foreign antigen.
I. Naturally acquired active immunity:
is immunity that comes from infections
encountered in daily life.

24. ii. Artificially acquired active immunity:
It is
stimulated by initial exposure to specific foreign
macromolecules through the use of vaccines to
artificially establish a state of immunity.

25. Major components of acquired
immune system-
 Cells that trap and process of antigen and them
present it recognition to the cells of immune system.
 Cells that have receptors for the processor antigen.
These cells can bind and response to antigen.
 Cells that once activated by antigen will produced
specific antibody or will participate in cell mediated
immune response.
 Cells that will retain the memory of the event and
react rapidly to the specific antigen. If it encounter at
later time (memory cells).

26.  Cells that regulate this response at an appropriate
level. All of these cell population can be recognized
with in the body.
 Antigen is trapped, processes and presented by
several cell type, that is- a) Dendritic cells, b)
Macrophage.
 The B and T lymphocytes have specific receptor for
foreign antigen and are thus able to bind the
processed antigen and respond apporopritily.

27.  Lymphocyte also function as memory cells and
initiate secondary immune response.
 The cell mediate immune response in mutated
by T cells and humoral antibody mediated B cells
 Those that permote immune response are called
as helper T cell and those that inhibit immune
response called as regulatory cells.