Immune System - The immune system is a complex network of cells and proteins that defends the body against infection. The immune system keeps a record of every microbe it has ever defeated so it can recognize and destroy the microbe quickly if it enters the body again. Abnormalities of the immune system can lead to allergic disease, immunodeficiencies and autoimmune disorders. Antigen - Any factors or agents that can enter the body and create an immune response are called antigen. Formation of immune cells - Immune cells are produced by hematopoietic stem cell in bone marrow Hematopoietic stem cells are self-renewing and reside in the medulla of the bone ( bone marrow ). HSCs are divided into two main lineages, lymphoid progenitor cells or myeloid progenitor cells. Myeloid cells - Neutrophil, Eosinophil, Basophil, Mast cells, Monocyte, Macrophage, Dendritic Cell Lymphoid cells - B Lymphocytes, T Lymphocyte, NK Cells Antigen presenting cells - Professional antigen presenting cells : Macrophage, Dendritic cell, B Lymphocyte Non professional antigen presenting cell: Non-professional antigen presenting cells include all nucleated cell types in the body. Proteins of immune system - Set of serum proteins that co-operate with both Innate and adaptive immune system to eliminate blood and tissue pathogen. Organs of immune cells - Spleen, Lymph node, Tonsils , MALT, Bone marrow, Thymus Types of immunity - Innate Immunity: Innate immune response is in born and is the first line of defense against pathogen Adaptive immunity: Antigenic specificity. It have immunological memory Immune Receptors - It is a specialized structures found in the cell membrane. They are mainly composed of proteins, which bind to pathogens and causes a response in immune system

1. General description of
Immune System from
modern expect
Presented by
Dr Shahnaz Bano
Department of Mahiyatul Amraz
Govt Tibbi College, Patna
Under supervision of
Asst Prof. Dr Md. Shamim Akther
Department of Mahiyatul Amaraz
Govt Tibbi college, Patna

2. 1. Immune System
2. Antigen
3. Formation Immune cells
4. Myeloid cells
5. Lymphoid cells
6. Antigen presenting cells
7. Proteins of immune system
8. Organs of immune system
9. Types of immunity
10. Receptors
Table of Content

3. What is the Immune
System?
• The immune system is a complex network
of cells and proteins that defends the body
against infection.
• The immune system keeps a record of every
microbe it has ever defeated so it can
recognize and destroy the microbe quickly if
it enters the body again.
• Abnormalities of the immune system can lead
to allergic disease, immunodeficiencies
and autoimmune disorders.

4. Parts of Immune System
PROTEIN
ORGANS
CELLS

5. Properties of Immune
System
• Complex process
• Limits pathogens proliferation
• Provide protection
• Create Immune response
• Helps cells communicate with each
other
• Self and non self distinction

6. What is Antigen
 Any factors or agents that can enter
the body and create an immune
response are called antigen.

7. Types of Antigen
Exogenous
• Bacteria
• Virus
• Parasites
• Fungi
Endogenous
• Faulty proteins
• Nucleoprotein
• Infected cells
• Cancer cell
Properties of Antigen
• Foreignness
• Proteineous in nature
• Size- 14 kilodalton to 600 kilodalton
• Epitope
• Host pathogen co-evolution

9. Formation of Immune cells
• Immune cells are produced by
hematopoietic stem cell in bone marrow
• Hematopoietic stem cells are self-renewing
and reside in the medulla of the bone ( bone
marrow ).
• HSCs are divided into two main lineages,
lymphoid progenitor cells or myeloid
progenitor cells.
• Lymphoid progenitor cells differentiate into
B and T cells and NK cells.
• Myeloid progenitor cells differentiate into
myelocytes (granulocytes and monocytes)
or non-leukocytes such as erythrocytes and
megakaryocytes (which produce platelets).

10. HSC
Myeloid cell
Granulocytes
Neutrophils
Eosinophils
Basophils
Mast cell
Antigen
presenting
cells
Monocyte
Macrophage
Dendritic cells
Lymphoid cell
T
lymphocytes
Helper cell
Cytotoxic cell
B
Lymphocytes
Memory cells
Plasma cells
NK cell

11. Myeloid cells
• Most abundant type of
granulocytes
• First Line Of Defense in bacterial
infection
• Make up 40% to 70% of all WBC
• Multilobes nucleus
• Phagocytic cell
• Release inflammatory molecules
like cytokines
• Highly motile
• Antimicrobial function
• It helps to regulate adaptive
immune response
Neutrophil

12. • Bilobed nucleus.
• Phagocytic cells
• Make up 1% to 6% of all WBC
• Fight against multicellular parasitic
organism.
• Its granules release cytotoxic
chemicals that are harmful to
parasites.
• Aggravates symptoms of allergy and
asthma
Eosinophil

13. • Make up about 1% to 3% of all WBC
• Nonphagocytic granulocytes
• Large granules that release histamine
which is responsible for vessels
permeability.
• It also release cytokines and other
molecules that target antigen that
cannot be killed by phagocytosis like
worm, helminth, parasite
Basophil

14. Mast cell
• A type of non phagocytic white blood cell
• Found in connective tissue especially
under the skin, near blood vessels, nerve,
intestine,
• Contain histamine, cytokines, growth factor
• 10 to 15 ng/ml
• Target the antigens by degranulation
• Respond against parasite, worm, and
allergens

15. • 2 to 10%
• Circulate in the bloodstream as
undifferentiated form
• They migrate from the blood to
the tissue and turn into tissue
resident macrophage
• two types
• Inflammatory monocytes
• Patrolling monocyte
MONOCYTE
Antigen presenting cells

16. Macrophage
macrophage
• Macrophages are specialized cells
involved in the detection,
phagocytosis and destruction of
bacteria and other harmful
organisms.
• They can also present antigens to T
cells and initiate inflammation by
releasing molecules (known as
cytokines) that activate other cells.
Microglial-brain
Mesangial-
kidney
Alveolar-lungs
Kupffer cell-
liver

17. Dendritic Cell
• Dendritic cells can develop from both myeloid
and lymphoid lineage
• bridging innate and adaptive immunity
• Detect, capture, engulf, processed of
pathogens
• Activation of the adaptive immune response
by presenting antigenic peptides on major
histocompatibility complex (MHC) molecules
to induce T cell activation and differentiation

18. B Lymphocytes
• B Lymphocytes are essential
cells of the adaptive immune
system.
• Developed and mature in bone
marrow.
• B cells are fewer in number than
T cells.
• During encounter of antigen B
lymphocyte differentiate into
Plasma cells and Memory cells.
• CD 19 surface marker present
on B cell surface
• B cell receptor also present on
its surface

19. T Lymphocyte
• Formed in bone marrow and
mature in thymus gland
• Part of adaptive immune
response
• Expressed T cell receptor on its
surface
• Eliminate virus, infected cells,
Tumor cells
• T cell are differentiate into CD8+
and CD4+ cells
• CD8+ T cells, also known as
"killer T cells", are cytotoxic –
this means that they are able to
directly kill virus-infected cells,
as well as cancer cells.

20. T cell
T helper
CD4+
T H1 T H17 T H2 T HF T Regulatory
T Cytotoxic
CD8+
Encounter the
Intracellular
pathogens
Encounter the extra
cellular pathogens
T regs control the immune
response to self and foreign
particles and prevent autoimmune
disease.
Destroy the
infected cells,
cancer cells

21. • NK cells are differentiate and mature in the
bone marrow, lymph nodes, spleen, tonsils,
and thymus,
• It does not require prior activation
• NK cells secrete cytokines, Interferon,
TNF-α, chemokines, and other factors
• Natural killer cells can be found in the skin,
uterus, kidney, joints, gut, liver, and breast
under normal physiological conditions.
• NK cells do not express any receptors on
its surface
• NK cell play essential role in antibacterial,
antiviral, antitumor activities
NK CELLS

22. Antigen presenting cells
• Mediate the cellular immune response ,Acts as a bridge between innate
and adaptive immune system
• Secretes some proteins during encounter of antigens which attract the
other immune cells
• phagocytose the pathogens and break them into peptides fragment
• APCs present these peptide fragment to other immune cells by MHC
class II molecules
• Antigen-presenting cells fall into two categories: professional and non-
professional.
• Those that express MHC class II molecules along with co-stimulatory
molecules and pattern recognition receptors are often
called professional antigen-presenting cells.
• The non-professional APCs express MHC class I molecule

23. Professional antigen presenting cells
• Macrophage
• Dendritic cell
• B Lymphocyte
Non professional antigen presenting cell
• Non-professional antigen presenting
cells include all nucleated cell types
in the body.

24. MHC/ Major histocompatibility
complex
• Its is very important part of the immune system
• Also called HLA (Human leucocytes antigen complex)
• MHC are a set of Genes, means its part of our DNA that is
encoded by specific proteins
• MHC proteins are cell surface proteins required for
adaptive immune response to recognize foreign molecules

25. FUNCTION
Binds with Peptide antigen and display them to T cells
MHC class 1 + Antigen T cytotoxic cells (CD8+)
MHC class 2 + Antigen T helper cells (CD4+)

26. Antigen presentation stimulates immature T cells to
become either mature "cytotoxic" CD8+ cells or
mature "helper" CD4+ cells.

27. Proteins/ Complement proteins
• Set of serum proteins that co-operate with both Innate and
adaptive immune system to eliminate blood and tissue
pathogen.
• These are Glycoproteins in nature.
• Complete the action of antibody.
How to Work
• Bind to opsonized pathogen
• Make pathogen susceptible for phagocytosis
• Create inflammatory response
• Eliminate apoptotic cells
• Kill pathogen by creating pore in microbial membrane

28. Immune system organs and its location
s

29. Organs of immune system
These are two types: Primary and
secondary lymphoid organs
Primary lymphoid organs
• Bone marrow
• Thymus
Secondary lymphoid
organs
• Spleen
• Lymph node
• Tonsils
• MALT(mucosa
associated lymphoid
tissue)
Function
Development and maturation of
immune cells
Function
Provide action area
for encountering of
pathogens

30. Types of immunity
THERE ARE TWO TYPES OF IMMNUNITY:
• Innate Immunity
• Adaptive immunity
• Immunity is the ability of the body to
defend itself against disease causing
organism,
Immunity

31. INNATE IMMUNITY
• It is non-specific.
• It is rapid response appearing within minutes.
• Innate immune response is in born and is the first line
of defense against pathogen.
• It has no memory.
• Does not provide long lasting immunity to the host.

32. COMPONENTS OF INNATE IMMUNITY
Physical barrier:
• Skin
• Eye
• Ear
• Mouth
• Mucus membrane
Chemical barrier:
• Cytokines
• Defencins
• Interferons
• Enzymes
• Body
temperature
• PH (stomach PH,
vaginal PH)
Cellular barrier:
• Monocyte
• Macrophage
• Dendritic Cells
• Neutrophils
• NK Cells
• Eosinophils
• Basophils

33. Adaptive immunity
• Also called Acquired immunity response
• It takes long time for activation (5 to 6 hours)
• Antigenic specificity
• It have immunological memory
• Its gives quite strong response
• Mediated by T and B lymphocytes

34. Types of Adaptive/acquired immunity
Types of Adaptive immunity
Cellular immunity
mediated by mainly T and B lymphocyte
Humoral immunity
mediated by Antibodies

35. Component of adaptive immunity
• B Lymphocytes
• Plasma cells
• T Lymphocytes
• T helper cells
• T cytotoxic cells
• T regulatory cells

37. Plasma
cell
The antibodies
Antibody
There are 5 classes of antibodies or
immunoglobulin produced by plasma cells
• IgG
• IgA
• IgM
• IgD
• IgE
Function
Bind to corresponding antigen,
and eliminate them.
Activate compliment proteins
Mediate allergic reaction

38. Memory B cell
Memory cells
Memory helper T cell
Subset of B and T lymphocytes differentiates
into memory cells which give long lasting
immunity to the host against specific
antigens.

39. Immune Receptors
• It is a specialized structures found
in the cell membrane.
• They are mainly composed of
proteins, which bind to pathogens
and causes a response in immune
system

40. Types of immune cells surface receptor
 Five main type of surface receptor
• Antigen receptor
• Co- stimulatory receptor
• Inhibitory receptor
• Cytokines receptor
• Chemokines receptor

41. Antigen receptor
• Immune cells can detect infectious agents and damage cells using receptor
• Two main types of Antigen Receptors:-
a) Pattern Recognition Receptors
PRR are able to recognize pathogen associated molecular pattern. PAMP and DAMP
etc.
Types of PRR
• Toll-like receptor
• NOD like receptor
• C- type lectin receptor (CLR)
• R1G like receptor (RLR)
b) Antigen specific lymphocyte receptor:
• B- cell receptor
• T- cell receptor

42. CD80, CD86, CD40
 Co- stimulatory Receptor
 Inhibitory receptor;
• Inhibitory receptor are important for regulating natural
killer cell activity.
• This prevents the NK cells from killing healthy cell.
 Cytokines receptor
 Chemokines receptor