Transcript Immune cells

Characteristics of
Immune Cells
B Y: J E N N I F E R B U I , K AT H Y L U U , D A N I E L M I R A N D A , T I N A Y I P
PHM142 Fall 2014
Instructor: Dr. Jeffrey Henderson
Immune System
Innate Immune System
Adaptive Immune System
First line of defense against
pathogens
Protects from reinfection
Innate Immune System

Physical Barriers

Inflammation

Complement System

Immune Cells

Neutrophils, eosinophils, basophils, macrophages, dendritic cells
Leukocytes
Basophils
Eosinophils
Neutrophils
Cells Involved in Innate Immunity
 Characteristics of Eosinophils

Stains Red

Receptors for IgE antibody

Responds to mainly parasitic infections

Granulocyte and Polymorphonuclear Leukocyte (PMN)
Cells Involved in Innate Immunity
 Characteristics of Basophils

Stains Purple/Blue

Cytoplasm filled with granules

Least Common

Contains Heparin

Contains Histamine

Granulocyte and PMN
Cells Involved in Innate Immunity
 Characteristics of Neutrophils

Most common leukocyte and has high motility

Attracted to site of infection by chemotaxins
Cells Involved in Innate Immunity
 Characteristics of Neutrophils

Performs phagocytosis

Destroys internalized microorganism with proteins from granules
Macrophages
 Phagocytic cell – Ingest and destroy microorganisms
Pattern Recognition Receptors (PRRs)
 Used to differentiate self from non-self
 Detect PAMPs
Macrophages
Dendritic Cells
 Long-finger like projections
 When immature – act as phagocytic cell
Dendritic Cells
B-cells

Many surface proteins

Very diverse -> nearly 1 billion different B-cells
CD268
(BAFF-R)
CD40
CD20
CD22
CD24
CD57
CD45R/B220
CD86
CD5
CD79a
Antibody
 Y-shaped protein

Recognize antigens
Variable
Region
 Variable region

Assembled via VDJ
recombination
Fixed
Region
B-cell receptor (BCR)
 Distinguishes B-cells from other immune cells
 Allows B-cells to: recognize antigens & general signal
Ligand binding
Signal transduction
Adaptive response
1. B-cell binds antigen
2. Antigen taken up and digested
3. Peptides presented on MHC II
4. Attracts T-cells
B-cell differentiation
Memory cell
 Retain bound receptor for
future
Plasma cell
 Produce antibodies
T Cell Receptors (TCR)
 The antigen must be:
1. degraded to short peptide
sequences
2. presented by APCs on MHC
molecules
CD4 (Helper) T Cells
 Activate macrophages
 Enhance inflammation
 Stimulate B cells to
produce antibodies
CD8 (Killer) T Cells
 Secrete cytotoxins and
cytokines to kill infected
cells
Cross-presentation
 Extracellular material from infected cell is
phagocytosed by APC to be presented on MHC class I
References

Mauri, C, Bosma, A (2012). "Immune Regulatory Function of B Cells". Annual Review of
Immunology 30, 221–41.

Murphy, K., & Travers, P. (2012). Janeway's immunobiology (8th ed., p. 5-7, 11, 77, 78, 347,
348). New York: Garland Science.

Owen, J., Punt, J., & Stranford, S. (2013). Kuby immunology (7.th ed., pp. 147-149). New York:
W.H. Freeman.

Parham, P. (2009). The Immune System (3rd ed., pp. 73, 79-81, 126, 133-134, 144-145, 227228). New York: Garland Science.

Silverthorn, D. U. (2012). Human Physiology: An Integrated Approach. (6th ed., pp. 131-134).
New York: Pearson.

Young, B., Lowe, J. S., Stevens, A., & Heath, J. W. (2006). Wheater's Functional Histology. (5th
ed., pp. 20-23) Newcastle: Elsevier Limited.
Summary slide
Cell Type
Physical Characteristics
Functional Characterisitics
Eosinophils
Visible granules, multi-lobed nucleus,
granules stain red with eosin
Primarily contain receptors for the IgE antibody, mainly fight
against parasitic pathogens
Basophils
Visible granules, multi-lobed nucleus,
granules dominate cytoplasm
Contains histamine for increased capillary permeability to
WBC’s, and heparin for anticoagulant properties.
Neutrophils
Visible granules, multi-lobed nucleus
Phagocytic functions, internalizes and destroys invading
microorganisms
Macrophages
Contain pattern recognition receptors
on its surface to identify pathogens,
example is mannose receptor
Primary role is phagocytosis, it engulfs the cell and breaks it
down using lysosomal hydrolase
Dendritic Cells
Long finger like projections, TLR, ICAM1 and ICAM-2
Immature dendritic cells are phagocytic, when they undergo
maturation, they become antigen presenting cells (APCs) and
now have the ability to present antigens to naïve T-cells
B cells
Spherical, many
surface proteins
Differentiate into memory cells (retain membrane bound
receptors) and plasma cells (produce antibodies)
Helper T Cells
TCR, CD4 coreceptors,
Secretes cytokines to enhance action of other immune cells: 1)
Activate macrophages 2) Enhance inflammation 3) Activate B
cell to produce antibodies