Intro

Immunology

• stems from latin word _ meaning “exempt” - english = protection from disease

• body's mechanism to discriminate between self and non-self antigens, eliminates non-self components (infectious agents)

immunis

Natural Immunity

• other terms:

• immunologic response:

• immunologic memory:

• lines of defense:

• other terms: innate/ non-specific

• immunologic response: immediate

• immunologic memory: absent

• lines of defense: first and secons

Adaptive Immunity

• other terms:

• immunologic response:

• immunologic memory:

• lines of defense:

• other terms: acquired/specific

• immunologic response: slow

• immunologic memory: present

• lines of defense: third

3 Lines of Body Defenses

• consists of the anatomical barriers that prevent infectious agents from infecting the body

• Ex: intact skin, mucuous membranes, cilia in respiratory tract, body secretions

First Line of Defense

Second Line of Defense

• Cellular component

Phagocytic cells (major component)

• PMNs, monocytes, macrophages

Antigen-Presenting Cells

• Dendritic cell (most effective)

• Monocyte, macrophage

Natural Killer Cells

Second Line of Defense

• Humoral Component

• Complement System

• Interferons

Third Line of Defense

Cellular Components

• Lymphocytes - B cells and T cells

Humoral Components

• Antibodies - IgG, IgA, IgM, IgD, IgE

• Cytokines

Stages of Phagocytosis

• Physical contact between the phagocytic cell and the microorganism/adherence

→diapedesis - migration of WBCs from capillaries to surrounding tissues

→chemotaxis - cells are attracted to site of inflammation by chemical substances

• Engulfment - outflowing of cytoplasm to surround the microorganism

• Phagosome - microorganism is completely enclosed

• Granule contact - lysosomal granules fused with phagosome

• Phagolysosome - contents of lysosome are emptied

• Digestion of microorganism by hydrolytic enzymes

• Excretion - contents of phagolysosoe are expelled outside by exocytosis

Nomenclature of Tissue Macrophages

• Liver

• Lungs

• Brain/Nervous Tissue

• Connective Tissue

• Skin/Mucosa

• Spleen

• Lymph Nodes

• Placenta

• Bones

• Kidneys

• Liver - kupffer cells

• Lungs - alveolar macrophages / dust cells

• Brain/Nervous Tissue - microglial cells

• Connective Tissue - histiocytes

• Skin/Mucosa - langerhan cells

• Spleen - splenic macrophages / Littoral cells

• Lymph Nodes - sinus histiocytes

• Placenta - Hofbauer cells

• Bones - osteoclast

• Kidneys - mesangial cells

Factors that enhance phagocytosis

• Toll-like receptors

• Opsonins

• Acute Phase Reactants

Toll-like Receptors (TLR) - found on human leukocytes and recognizes different microbial products

• TLR 1 -

• TLR 2 -

• TLR 3 -

• TLR 4 -

• TLR 5 -

• TLR 6 -

• TLR 7 -

• TLR 8 -

• TLR 9 -

• TLR 10 -

• TLR 1 - human cells → lipopeptides (Mycobacteria)

• TLR 2 - brain, heart, muscle, lungs → peptidoglycan (Gram-positive bacteria)

• TLR 3 - placenta and pancreas → double-stranded RNA (RNA viruses)

• TLR 4 - placenta, cardiomyocytes, endothelial cells, smooth muscle cells → lipopolysaccharide (Gram-negative bacteria)

• TLR 5 - placenta, cardiomyocytes, endothelial cells, smooth muscle cells, ovaries → flagellin

• TLR 6 - thymus, spleen, ovary, lungs → lipopeptides ( Mycobacteria)

• TLR 7 - plasmacytoid dendritic cells → single-stranded RNA (RNA viruses)

• TLR 8 - monocyte-derived dendritic cells → single-stranded RNA (RNA viruses)

• TLR 9 - cytosine-phosphate-guanine in double-stranded DNA viruses

• TLR 10 - dendritic cells and activated B cells → HIV gp41 and LPS

• subtances that coat foreign cells and pathogens to make them more susceptible to phagocytosis

• derived from the greek word meaning, “to prepare for eating”

Opsonins

Opsonins

• Ex:

• CRP

• C3b

• Antibodies

Acute Phase Reactants

• normal serum constituents that increase by at least _ due to infection, injury, or trauma to tissues

• produced primarily by hepatocytes within _ hours

• Ex:

• normal serum constituents that increase by at least 25% due to infection, injury, or trauma to tissues

• produced primarily by hepatocytes within 12 to 24 hours

• Ex:

→CRP

→C3

→Fibrinogen

→Haptoglobin

→Serum Amyloid A

→Alpha-1 Antitrypsin

→Ceruloplasmin

Types of Acquired Immunity

• Active

Type:

Antibody produced by host:

Duration of response:

• Passive

Type:

Antibody produced by host:

Duration of response:

• Active

Type: Natural Active (Infection), Artificial Active (Vaccination)

Antibody produced by host: Yes

Duration of response: Long

• Passive

Type: Natural Passive (Placental transfer of IgG, Colostrum), Artificial Passive (Convalescent plasma)

Antibody produced by host: No

Duration of response: Short

T Cells

%:

Immunity:

Products:

Defense against:

Surface markers:

→ _ - E-rosette receptor

→ _ - part of T cell antigen receptor

→ _ - Helper T cell/Treg cell

→_ - early stages of T cells

→ _ - cytotoxic T cell

%: 60 - 70%

Immunity: cell-mediated

Products: cytokines and cytotoxins (perforins and granzymes)

Defense against: viral and fungal infections, tumor and graft rejections

Surface markers:

→ CD2 - E-rosette receptor

→ CD3 - part of T cell antigen receptor

→ CD4 - Helper T cell/Treg cell

→CD5, CD7 - early stages of T cells

→ CD8 - cytotoxic T cell

B Cells

%:

Immunity:

Products:

Defense against:

Surface markers:

→ _ - part of B cell co-receptor

→ _ - binding activates signalling pathway

→_ - receptor of C3d and EBV

→ _ - mature B cells

→ _ - early stages of B cells

%: 10 - 20%

Immunity: Humoral-mediated

Products: Antibodies

Defense against: Bacterial infections

Surface markers:

→ CD19 - part of B cell co-receptor

→ CD20 - binding activates signalling pathway

→CD21 - receptor of C3d and EBV

→ CD22 - mature B cells

→ CD10 - early stages of B cells

%:

Immunity:

Products:

Defense against:

Surface markers:

→ _ - receptor for IgG

→ _ - no known function

%: 10 - 15%

Immunity: recognition of missing self and ADCC

Products: cytotoxins (perforins, granzymes)

Defense against: virally infected cells, tumor cells

Surface markers:

→ CD16 - receptor for IgG

→ CD56 - no known function

• rapid and convenient technique for generating immunophenotypic data of cells

• useful for evaluation and prognosis of leukemia, lymphoma and immunodeficiency

• based on light scaterring derived from suspension of particles of a flowing stream of fluid

Flow Cytometry

Flow Cytometry - Major Components

• _ - cells are suspended in a stream of isotonic saline

• Laser light source - _ are typocall used a slight sources

→ _ - indicator of cell size

→ _ - indicator of granularity / intracellular complexity

• _ - added to quantify cell subpopulation or cell components, identifies surface and cytoplasmic antigen expression

• Optics and Photodetectors - the various signals (light scatter and fluorescence) generated are detected by _ for FSC and ) tubes for fluorescence

• FLUIDICS - cells are suspended in a stream of isotonic saline

• Laser light source - SOLID-STATE DIODE LASERS are typically used as light sources

→ FORWARD-ANGLE LIGHT SCATTER - indicator of cell size

→ RIGHT ANGLE / SIDE LIGHT SCATTER - indicator of granularity / intracellular complexity

• FLUORESCENT LABELED ANTIBODIES- added to quantify cell subpopulation or cell components, identifies surface and cytoplasmic antigen expression

• Optics and Photodetectors - the various signals (light scatter and fluorescence) generated are detected by PHOTODIODES for FSC and PHOTOMULTIPLIER tubes for fluorescence

Subsets of T helper T cells

• _ - protect cells against intracellular pathogens by activating cytotoxic lymphocytes and macropahges

• _ - help B cells produce antibodies against extracellular pathogens and regulate B cell activity

• _ - has an important role in supressing immune response to self antigens

• _ - promotes inflammation; defense against fungi and bacteria, stimulates growth of mast cells

• _ - promotes inflammation; associated with RA (joint destruction), multiple sclerosis, IBD

• Th1 - protect cells against intracellular pathogens by activating cytotoxic lymphocytes and macropahges

• Th2 - help B cells produce antibodies against extracellular pathogens and regulate B cell activity

• Treg - has an important role in supressing immune response to self antigens

• Th9 - promotes inflammation; defense against fungi and bacteria, stimulates growth of mast cells

• Th17 - promotes inflammation; associated with RA (joint destruction), multiple sclerosis, IBD

• capable of trigerring an adaptive immune response by inducing formation of antibodies/sensitized T cells

• HIGH MW, molecular complexity, protein

• at least 10,000 daltons

Immunogen

• can combine with antibody but may or may not invoke an immune response

• LOW MW, molecular complexity, non-protein

antigens

• All immunogens are antigens, but not all antigens can be immunogens (haptens)

• _ - is the portion of antigen /immuniogen that is recognized by T cells, B cells, antibodies

• power of immunogens to generate an immune response can be increased by _

• All immunogens are antigens, but not all antigens can be immunogens (haptens)

• EPITOPE - is the portion of antigen /immuniogen that is recognized by T cells, B cells, antibodies

• power of immunogens to generate an immune response can be increased by ADJUVANTS

Major Histocompatibility Complex

• also known as _

• genes coding for MHC molecules are found in short arm of _

• functions:

→mounting immune responses

→determines histocompatibility

→disease association

• also known as HUMAN LEUKOCYTE ANTIGENS

• genes coding for MHC molecules are found in short arm of CHROMOSOME 6

• functions:

→mounting immune responses

→determines histocompatibility

→disease association

Major Histocompatibility Complex

• Ankylosing Spondylitis →

• Goodpasture Syndrome →

• Systematic Lupus Erythematosus →

• Rheumatoid arthritis →

• Celic disease →

• Behcet's Disease →

• Myasthenia gravis →

• Type I DM, Multiple Sclerosis →

• Ankylosing Spondylitis → HLA-B27

• Goodpasture Syndrome → HLA-DR2

• Systematic Lupus Erythematosus → HLA-DR3

• Rheumatoid arthritis → HLA-DR4

• Celic disease → HLA-DQ2, HLA-DQ8

• Behcet's Disease → HLA-B51

• Myasthenia gravis → HLA-B8

• Type I DM, Multiple Sclerosis → HLA-DQ, HLA-DR

Classes of Antibodies

IgG Subclasses - differ in number and linkages of _

• IgG1 - _%

• IgG2 - _%

• IgG3 - _%

• IgG4 - _%

IgG Subclasses - differ in number and linkages of DISULFIDE BONDS

• IgG1 - 66%

• IgG2 - 23%

• IgG3 - 7%

• IgG4 - 4%

IgM

• found mostly in _ pool

• phylogenetically the most _ among Igs

• most efficient in _

• found mostly in INTRAVASCULAR pool

• phylogenetically the most PRIMITIVE among Igs

• most efficient in AGGLUTINATION REACTIONS and COMPLEMENT FIXATION

IgA1 - monomer, found in _

IgA2 - dimer, found in _, contains _

IgA1 - monomer, found in SERUM

IgA2 - dimer, found in SECRETIONS, contains J CHAIN and SECRETORY COMPONENT

Actions of Anaphylatoxin (C4a, C3a, C5a) - from complement system

• increases vascular permeability

• contraction of smooth muscle

• release of histamine from basophils and mast cells

Complement System

• central convergence point: _

• highest cons. in plasma: _

• highest moecular weight: _

• opsonin: _

• chemotaxin: _

• most potent anaphylatoxin: _

• central convergence point: C3

• highest cons. in plasma: C3

• highest moecular weight: C1q

• opsonin: C3b

• chemotaxin: C5a

• most potent anaphylatoxin: C5a

Inherited deficiences in Complement and Complement-Related Proteins

• Glomerulonephritis, SLE -

• Severe Recurrent Infections -

• Disseminated Neisseria infections -

• No known -

• Neisseria mengitidis infection -

• Recurrent pyogenic infcetions -

• Hereditary angioedema -

• PNH -

• Glomerulonephritis, SLE - C1, C2, C4

• Severe Recurrent Infections - C3

• Disseminated Neisseria infections - C5, C6, C7, C8

• No known - C9

• Neisseria mengitidis infection - Factor B

• Recurrent pyogenic infcetions - Factor D, properdin, mannose-binding lectin

• Hereditary angioedema - C1 INH

• PNH - Decay accelerating factor, membrane inhibitor of reactive lysis

DILUTION

• represents the ratio of concentrated stock material to the total final volume of a solution

• an indication of _ and maybe expressed as fraction or ratio

• Types: _

• Formula:

• represents the ratio of concentrated stock material to the total final volume of a solution

• an indication of RELATIVE CONCENTRATION and maybe expressed as fraction or ratio

• Types: SIMPLE, SERIAL, COMPOUND

• Formula:

1/ Dilution -1 = vol. solute/ vol. of solvent

1/Dilution = vol of solute/total volume

Percentage of persons with the disease who have positive test results

Clinical Sensitivity

Formula:

TP/TP + FN x 100

Percentage of persons without the disease who has a negative test result

Clinical Specificity

Formula:

TN / TN+ FP x 100

Probability of an individual having the disease if the result is abnormal or ouside the reference range

Positive Predictive Value

Formula:

TP / TP + FP x 100

Probability that an individual does not have a disease if the result is normal or within reference range

Negative Predictive Value

Formula:

TN / TN + FN x 100