Overview of immune cells,

1. BY
A.MANOJ KUMAR

2.  Ag -Antigen
 Ab -Antibody
 MHC -Major Histocompatibility Complex
 NK -Natural Killer Cell
 Ig -Immunoglobulin
 APC -Antigen Presenting Cell
 PMNs -Polymorphonuclear leucocyte
 CD -Cluster of Differentiation
 Fc -Crystalizable fragment
 WBC -White Blood Cell

3.  The immune system operates by producing
immune cells.
 The immune cells arise from Haematopoietic
Stem cells from where they differentiate into
many types of cells.

5.  Lymphocytes are the central cells of the
immune system responsible for adaptive
immunity.
 The Lymphocytes are active based on 4
immunological atritute such as
1) Antigenic Specificity
2) Antibody Diversity
3) Immunological memory
4) Self / Non-self Recognition

6.  Lymphocytes constitute 20-40 % of the bodies
WBC
 There are approximately 10 cells of Lymphocytes
present in human body.
B CELLS
 B cells origin and mature within the bone
marrow, When they leave it ,each cells are
expressed a unique Ag binding receptor on the
surface of the B cells.
 This binding or B cell receptor is membrane bound
antibody molecules.

8.  When a native B cells (The one that has not
previously encound Antigen)
 The binding of Ag-Ab complex causes the cell to
divide rapidly and differentiate into plasma B cell
and memory cell.
PLASMA CELLS
 Plasma B cells produces Ab is secreted form and
produce enormous amount of more than 2000
molecule per second / cells
 B cells forms the basics of Humoral mediated or Ab
mediated Immune response

10.  The plasma cells can stay only for a few days or
weeks
 Plasma B cells are the cells that generated during
primary immune Response
 The markers present in the B cells are B220,B7-
1,B7-2,CD40.
MEMORY CELLS
 Memory B cells are generated during Primary
immune Response and reproduce the same
membrane bound Ab molecule during the
Secondary immune Response

11. T CELLS
 T Lymphocytes origin from bone marrow and
migrate to thymus gland for maturation
 During maturation T cell express its Unique
antigen binding molecule called T-cell receptor ,
on its surface membrane
 Unlike B cells which can directly can recognize
the Ag alone, But T cells receptor can recognize
the Ag bound with cell membrane protein called
MHC molecule expressed by APC or all Nucleated
cells.

12.  When the naive T cells encound the antigen in the
secondary organ , that is complexed with class 1 &
2 MHC molecule, the T cell divides / proliferate
and differentiate into plasma T cells and Memory
cells
 The plasma T cell further differentiate into a helper
T cell and Cytotoxic T cell.
 The helper T cell and Cytotoxic T cell can be
distinguish based on the marker present on the
surface of the cells
 T-Helper cell display CD4 marker
 T-cytotoxic cell display CD8 marker

13.  Natural killer cells is a large granular
Lymphocytes that have cytotoxic actitivity against
the tumour cells
 It constitute 5-10% of the human blood
 Enhance do not express membrane molecule or
receptor like B & T cell receptor
 Against the tumour Ag specific Ab mediated
immune response develops, such complex
(Tumour Ag-Ab) binds to Fc receptor of NK cells.

15.  Eg-NK Cell Expresses CD16 receptor,a
membrane receptor on the surface of NK cell for
the carboxyl terminal end of Ig G molecule such a
process of cytotoxicity is called ADCC ( Antibody
Dependent Cell-Mediated Cytotoxicity
MYELOID CELLS
 Mononuclear phagocytes-
1.Monocytes 2.Macrophage
 Polymorphonuclear Leukocytes
1.Eosinophil,2.Basophil,3.Neutrophil,4.Mast
cell,5.Dendritic Cell

16. MACROPHAGE
Stem cell bone marrow
Monocyte Progenitor cells
Promonocytes
Which leave the bone marrow and circulate in
blood for 8hrs,where they mature into monocytes
Then,they enlarge migrate into tissue and
differentiate into tissue specific macrophage

18.  Macrophage serve different function in different
tissue and are named according to their location
 Lung - Dust cells
 Connective tissue -Histocytes
 Liver -Kupffer cells
 Kidney -Mesangial cells
 Brain -Microglial cells
 Bone -Osteoclasts

19.  Macrophages act as the APC and help activation of
T cells( Both T H& C cells)
 It involved phagocytosis

20. Opsonization
 The rate of phagocytosis of Ag was fold 4000-
fold higher in the presence of specific Ab. Here
the antibody function as opsonin the entire
process called Opsonization
 The complex of Ag-Ab binds the Antibody
receptor on the membrane of the macrophage
and phagocytosis is enhance

21. PMNs or Granulocytic cells are classified into
 1.Eosinophil,
 2.Basophil,
 3.Neutrophil,
 4.Mast cell,
 5.Dendritic Cell .
 based on the cellular morphology of the cell,
cytoplasmic staining characteristic

22. NEUTROPHILS
 Neutrophils has a multilobed nucleus and
granulated cytoplasm
 It constitute 50-70% of the circulating WBC
 Neutrophils origin from bone marrow and circulate
in the blood for 7-10 hrs before migrating to the
tissue
 These cells are the first arrive at the site of
inflammation, resulting in the increase the no of
circulating Neutrophils, called leukocytosis

23.  It is used medically as a indication of infection
 Granules contain
 1.primary granules-Peroxidase, lysozyme,
Hydrolytic enzyme
 2.Secondary Granule- Collagenase,
Lactoferrin,lysozyme

24. EOSINOPHILS
 Eosinophil like neutrophil are motile phagocytic
cell
 Its originate from bone marrow and circulate in the
blood and migrate into tissue
 It constitute 1-3% of circulating WBC
 It has bilobed nucleus and granulated cytoplasm
that stains with eosin dye that is called Eosinophils
 It place the major role in the defence against
parasitic infection

26. BASOPHILS
 Basophils are non-phagocytic granulocytes.
 It consitute less than1 % of the total circulating
WBC.
 Thy play a major role in certain allergic response.
 The granules present in the basophils contain
pharamacologically active substance

28. MAST CELL
 It originates from the bone marrow and released
into the blood as undiffrentiated cell and
differentiated into mast cell in tissue
 The mast cell can be found in skin, connective
tissue of various organ, mucosal epithelial tissue
of respiratory and digestive track
 It plays a major role in Allergic reaction
 It contains large cytoplasmic granule, which
contain histamine and pharamacologically active
substance

29. DENDRITIC CELLS
 It is an APC that process the antigen into antigenic
peptide and form a complex with MHC class 1 &2
molecule and present it into the T cell for the T- H
& C cell activation
 It is origin from Haematopoietic stem cell
 There are 4 types of Dendritic cells
1.Laugerham cell
2.Interstitial Dendritic cells
3.Myeloid cells
4.Lymphoid Dendritic cells