Introduction of immunology
Prof. Dr. Ruqaya M. Al Barzinji
Hawler Medical University
College of Medicine
Department: Microbiology
Lecture 1:
Contents
● Objective
● Definition of immunity
● Branches of immunology
● Application of immunology
● Terms in immunology
● Cells of immune system
Objective
● The student must be learn definition ,
branches and application of immunology. Also
there are many immunological terms should be
learned by students.
Definitions of immunology:-
Branch of medical science that deals with the
study of development and function of both
cellular and humeral components of the
immune system by which the body reacts to
expel, destroy or neutralize foreign substances
including pathogenic microorganisms.
Immunity:-
● Refers to all the physiological mechanisms that
allow the body with the capacity to recognize
materials as foreign to it and to neutralize,
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eliminate or metabolize them. karegare-hawkeshkr
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● Although the usual outcome of immune response
is beneficial, it may cause harmful effects such
as autoimmunity and hypersensitivity.
● Immunis is a Latin word meaning free from
burden or taxes.
Branches of immunology:-
● 1-Immunochemistry: Deals with the chemical
nature of antigen, antibody and their
interactions.
● 2-Immunobiology: Related to biologic functions
of the cells and tissue component of the
immune system.
● 3-Immunogenetics: Study of immunoglobulin
genes and the genetic basis of immune
response.
Branches of immunology:-
● 4-Clinical immunology: Deals with pathogenesis,
diagnosis and treatment of immune mediated
diseases.
● 5-Immunotherapy: Deals with prevention and
treatment of diseases by immunological meanse
as vaccination, immunoglobulin therapy and
desensitization.
process or act of making less sensitive
Branches of immunology:-
● 6-Immunohematology: Deals with immunological
basis involved in different hematological
disorders
● 7-Immunopharmacology: Deals with the
pharmacological action of different secreted
molecules in immune responses.
● 8-Serology: Study of immune reactions mediated
by antibodies or immunoglobulins present in the
serum.
Application of immunology
● 1-Diagnosis of diseases: By detecting antibody
or antigen it help in diagnosis of many diseases.
● 2-Understanding disease process: Immunology
can explain the pathogenesis of infectious,
autoimmune, neoplastic and many other diseases.
is an abnormal growth of cells also known as
tumor
Application of immunology
● 3-Prevention and treatment of diseases:
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Immunization against many diseases by vaccine
and immunoglobulins also in management of
cancer in future.
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● 4-Blood transfusion serology: Grouping, typing and
cross matching in Blood transfusion.
● 5-Tissue typing and histocompatibility testing
necessary for successful organ transplantation.
● 6-Forensic medicine: such as paternity testing.
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compatibility between the tissue of different
individual so that the one accepts a graft
from the other without giving an immuno
reaction
Immune components: are divided
into:-
● 1- Humeral factor: (Immunoglobulins,
Complement system, Cytokines).
● 2- Cellular factor: (Lymphocytes, phagocytes)
Common terms in immunology
● Antigen:-
● It is a foreign substance when inter to the body may
cause stimulation of immune system.
● Immunoglobulins(Antibodies):-
any of a class of proteins which have carbohydrate groups attached to the
● Are glycoprotein that bind specifically to the
polypeptide chain.
antigen that induced their formation, they produced
from plasma cells as a result of activation of B –
cells through acquired immune response. The
types of immunoglobulins(Igs) are IgM, IgG, IgA,
IgD and IgE. The five primary classes of immunoglobulins are IgG, IgM, IgA, IgD and
IgE. These are distinguished by the type of heavy chain found in the
molecule. IgG molecules have heavy chains known as gamma-chains;
IgMs have mu-chains; IgAs have alpha-chains; IgEs have epsilon-chains;
and IgDs have delta-chains.
The complement system:-
● Is a group of serum proteins consist of 9
component C1-C9, present in low and in an
active form, but can be activated to form an
enzyme cascade leading to destruction the
target substance.
● Activation of complement component occurs
by classical pathway alternative pathway
and lectin pathway.
Cascade: A sequence of successive activation reactions involving enzymes (enzyme
cascade) or hormones (hormone cascade) characterized by a series of amplifications
of an initial stimulus. In blood coagulation, for example, each enzyme activates the
next until the final product, the fibrin clot, is reached
The complement system is so named because it is complementary to the antibody
response of the adaptive immune system. ... After the first few complement proteins
bind, a cascade of sequential binding events follows in which the pathogen rapidly
becomes coated in complement proteins.
Cytokines:-
● Are low molecular weight soluble
glycoproteins.
● They are immunomediators produced after
stimulation of immune system play important
role in regulation and orchestrate the
immune system and immune respone.
● Examples on cytokines are lymphokines,
monokines, adipokine, chemokine and
interleukins.
Major histocompatibility complex
(MHC):-
● Cell surface proteins or antigens that coded by a
cluster of genes present on chromosome number
6, they are polymorphic within a species and
responsible for graft rejection between members
of the same species which differ at these loci.
● In human the MHC called HLA and classified into
3 classes they are class 1, class II and class III.
To prevent an attack on our own cells and tissues (autoimmunity), the immune
system must be able to differentiate between our own healthy tissues and foreign
invaders. ... Graft rejection occurs when the recipient's immune system attacks
the donated graft and begins destroying the transplanted tissue or organ.
Cluster of differentiation (CD)
● The cluster of differentiation (cluster of
designation or classification determinant is
cell surface glycoprotein used for the
identification and investigation of cell
surface molecules
● Acting as receptors or ligands, cell signaling,
cell adhesion.
● CD for humans is numbered up to 371 till
2016
Cells of immune system can be
classified into:-
● 1-Myloied linage
● 2- Lymphoid linage:-
● The myeloid linage include:-
● A-Mononuclear phagocytes: They are found in the
blood and in tissues. In the blood they are known as
monocytes while in the tissues they differentiate into
different histologic forms for example
● 1-In connective tissue they are known as histocytes
2-In the kidney as measangial cells
● 3- In bone as osteoclasts
● 4-In brain as microglia
● 5- In the spleen, lymph node and thymus as the
sinus lining macrophage
● 6- In the liver as Kupffer cells
● 7- In the lungs as alveolar macrophage
● 8-Peritonial macrophage, free floating in
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peritoneal fluid
B-Multinuclear phagocyte:
● Polymorphonuclear cells(PMN) are include
Neutrophil, eosinophil and basophile they kill
the target by increase phagocidal activity
mechanisms.
The lymphoid linage include:-
A-Small a granular lymphocyte
● 1-B-lymphocyte (B-cell)
● 2- T-lymphocyte (T-cell), sub classified into
● A: T-helper (Th-cell)
● B: T-cytotoxic (Tc-cell)
● C: T-suppressor (Ts-cell)
● B-Large granular lymphocyte
● Natural killer cells (NK cells):-NK cells are large
granular lymphocytes, they play a role in the early
stages of viral infection and tumorogenesis.
Organs of the immune system:-
– Primary lymphoid organs.
– Secondary lymphoid organs.
Summary
● Immunity refers to all those physiological mechanisms
that used by the body to resist agents that are foreign
to it.
● There are many branches of immunology .
● There are many application for immunology.
● Definition to many terms in immunology.
References
● Text book of immunology, edited by SK Mohanty and K
Sai Leela; 2006.India.
● Medical microbiology and immunology, edited by
Levinson W. 2006, Lange.
● Cellular and molecular immunology , edited by Abbas
A.K.; Lichtman A.H. and Pillai S.6th edition
2007,USA.
● Clinical immunology, edited by Chapel H. 5th edition
2010, UK.
● Internet access.
Thanks a lot
