Immunity and their types

1. Shri Shankaracharya Mahavidyalaya,Junwani,Bhilai
Immunity
Dr. Sonia Bajaj
(Head of Department)

2. Introduction
Immunology is the branch of Biology. It is concerned with immunity. It is
resistance of living organism to infection of microorganisms.
It deals with the study of process by which the body defends itself from the
invasion and attack of foreign organisms.
In ancient times, the term immunity was used only to mean “exemption from
Military Service or taxes” (Latin word immunities- freedom from) and later it was
introduced into medicine to refer to the human beings who do not get further
attack of disease like smallpox or plague, once they contact those diseases.
Immunity is defined as the resistance to infection. This is carried out by the
process of recognition and disposal of non- self or foreign material that enters
the body. The non- self is the life threatening infectious microorganisms or it
may be tissue graft.

3. Types of Immunity

5. Types of immunity- Immunity is broadly classified into two types-
•Innate immunity
•Acquired immunity
1. Native immunity/ innate immunity/ natural immunity- All living organisms are
naturally gifted with the resistance to certain infection from birth and this natural
defence mechanism is known innate immunity.
As the innate immunity include the general protective reaction of organisms
against any invention and not against any particular microorganism. It is also
known as non -specific immunity.
Innate immunity is provided by various components such as skin, mucus
membrane, phagocytic cell etc.
2. Acquired immunity/ adaptive immunity - The residence developed by man
during his life is known as acquired immunity.
This is distinct from innate immunity in that it is due to specific antibodies or
sensitized Lymphocytes produced in response of specific antigens. Hence, this
community is also known as specific immunity.
• This acquired specific immunity is of two types namely active and passive. Both
active and passive immunity may be natural or artificial. Acquired immunity is
provided by Antibodies and certain T-lymphocytes ex. chicken pox virus

6. Types of acquired immunity
Active immunity
Passive immunity
1. Active immunity:
If host itself produces antibodies, it is called active immunity.
It is of two types; artificial active immunity and natural active immunity.
Artificial active immunity: Immunity provided by vaccination.
Natural active immunity: immunity provided by natural infection.
Active immunity involves the synthesis of specific antibodies (humoral
immunity)
or
Production of immunologically active cell (cell mediated immunity).

7. Humoral immunity
• Humoral immunity mediated by antibodies produced in the humors or body
fluids such as plasma or lymph is known as humoral immunity.
• In this, specific antibodies are produced in response to a specific antigen
stimulus. Ultimately the antigen (microorganisms) may be clumped, their
toxicity may be naturalized and their phagocytosis may be facilitated.
Cell mediated immunity
• Cell mediated immunity produced by the synthesized lymphocyte is called cell
mediated immunity.
• Here antibody or not produced. The sensitized lymphocyte reacts with the
specific antigen and brings about the cytotoxic effects resulting in the lysis of
the microbial antigens.
• If an individual is exposed to a particular antigen for the second time, immune
response occur more quickly and more abundantly than during the first
exposure. This is known as secondary response.
• Both humoral and cell mediated immunity are associated with immunologic
memory which the immune system is able to retain the memory of the first
antigenic exposure and thereby during the second similar exposure it produces
a quick response.

8. 2. Passive immunity:
If host does not produce antibodies itself but antibodies produced in other host
provides immunity, than it is known as Passive immunity.
It is of two types; natural passive immunity and Artificial passive immunity
Natural passive immunity: IgG antibody produced in mother cross placenta and
protects fetus up to 6 month old age.
Artificial passive immunity: if preformed antibody are injected into host for
immunity. Ex. Anti-venom, Rabies vaccine
(* it is not a vaccine, it is preformed anti rabies antibody)

10. • Interferon's (IFN)
• These are a group of soluble, non-toxic, glycoprotein produce in small amounts
by all the cell of body.
• This is an antiviral agent which inhibits intracellular viral replication in cell
infected with viruses.
• Interferon appears in the cells before any detectable antibody for the virus
could appear. It offers residence by blocking viral mRNA transcription thereby
disrupting the viral life cycle.
• Interferon also enhances N K cell activity thus offering immunity to cancer. They
also inhibit cell proliferation in tumours and thereby assuring its use in Cancer
chemotherapy. Because of their antiviral and anticancer properties, large
quantities of interferon are commercially prepared to help in the treatment of
viral infection and in Cancer therapy.
• The manufacture of interference is a major breakthrough in Science, as genes
for human interference have been introduced in E. coli genome to produce
interference by E. coli.( DNA Recombinant technology)
• On the basis of their electrophoretic mobility, the interferons are grouped into
Alpha interferon, beta and gamma interferon. Interferon is specifically produce
only by activated T- lymphocytes.

11. References-
Immunology –D.Fatima
Immunology – Kuby
Jantu Vigyan- S.M. sexsena
Jantu Vigyan- Dr.H.N. Baijal