Oral Biology, 10/13/11

Front 1

Name 3 functions of the immune system

Back 1

 To constantly distinguish and identify between “self” and “non-self”
 To protect host integrity through defense system
 To maintain homeostasis of the body by surveillance system

Front 2

2 interactive arms of the immune system

Back 2

1) The innate (natural or nonspecific) immunity
2) The adaptive (acquired or specific) immunity

Front 3

What are the components of innate immunity?

Back 3

 Natural Barriers: skin, compartmental isolation etc.
 Cellular: (Macrophages, Mast cells, Granulocytes, Natural killer
cells, dendritic cells,  T cells).
 Complement system
 Chemicals: HCL, lysozyme

Front 4

What are the characteristics of innate immunity?

Back 4

esponse/effect is immediate, fast launch
 Response is non-specific
 Response is of same intensity, not enhanced on repeated exposure
to antigen/pathogen

Front 5

Two folds of the innate immune system - describe characteristics of each one

Back 5

Non-inflammatory defense (static):
 skin - stratified epithelial cells as barrier to bacteria and viruses
 gastric fluid – low pH
 tears, saliva, mucous - antibacterial lysozyme
 hair follicles and sebaceous glands – fatty acids and enzymes
 normal gut flora - compete with potential pathogens
Local inflammatory defense (active):
 Phagocytes – recognize surface structures of common microorganisms
(peptidogcan, mannose) and destroy them by phagocytosis.
 Natural killer cells - eliminate infection by releasing toxic compounds
 Serum components - acute phase proteins (e.g. C-reactive protein)

Front 6

Characteristics of the adaptive immune system

Back 6

• Action requires hours, days or months to develop
• Response is specific and intense
• Response is enhanced on repeated exposure to antigen/pathogen

Front 7

Mechanism of humoral immunity - what is this mediated through?

Back 7

B-lymphocytes produce antibodies to recognize and bind
specifically to antigens

Front 8

What is action 1 of the B lymphocytes?

Back 8

Action 1: Antitoxin neutralize bacterial toxins as a result of
 Previous infection
 Artificial immunization
 Transferred passively as antiserum

Front 9

What is action 2 of the B lymphocytes?

Back 9

Action 2: Antibodies binding to bacterial antigen
 Act as opsonins and enhance phagocytosisd
 Prevent the adherence of microorganisms to their target cells
 Activate the complement leading to bacterial lysis
 Bacteria agglutination leading to phagocytosis

Front 10

Describe the mechanism of cell mediated immunity

Back 10

 It is mediated by certain types of T-lymphocytes
 T-lymphocytes recognize foreign material by means of surface receptors
(TCR)
 T-lymphocytes attack and destroy foreign material directly (NK cells) or
through release of soluble mediators (cytokines, chemokines) and
activation of other cellular components (B cells, Macrophages) for
expanded immune responses

Front 11

Adaptive immune system..
1. Specificity
2. Accuracy
3. Diversity
4. Synergy

Back 11

 Specificity - Highly specialized than innate immune response
 Accuracy - Response only to “non self ” molecules
 Diversity - Respond to millions of different antigens
 Synergy - Interact with one another to destroy foreign body
 Involves a combination of two mechanisms :
1) Humoral immune response
2) Cell-mediated immune response

Front 12

Describe hematopoietic leukocytes

Back 12

Antigen specific cells carrying CD3 complex, CD4, CD8
- Dominant blood lymphocytes (70%)
- Produce cytokines
- Activation of other cells (Th CD4)
- Suppressors for others (Ts CD8)

Front 13

B lymphocytes and natural killer cells (NK)

Back 13

* B lymphocytes:
- Antigen specific cells with surface receptor
- Less common lymphocytes (20%)
- Responsible for antibody production
* Natural Killer (NK) cells:
- Not antigen specific
- Carry Fc receptors , NK-target cell receptor

Front 14

Monocytic myeloid cellular component

Back 14

* Monocyte-tissue macrophages:
- Non specific
- Carry Fc receptors
- Phagocytic
- Antigen processing and presenting cells
- Produce cytokines
* Neutrophils:
- Non specific
- Carrying Fc, complement molecules

Front 15

Describe eosinophils and basophiles and mast cells

Back 15

* Eosinophils:
- Non specific
- Carrying Fc receptor
- Produce allergic mediators
* Basophils and Mast cells:
- Non specific
- Carrying Fc receptors
- Produce allergic mediators

Front 16

In the cellular components, what are some non hematopoietic cells

Back 16

Dentritic cells
* Astrocytes
* Epithelial cells and Endothelial cells
* Fibroblasts
Function : Antigen Presentation and Cytokine Production;
Coordinated network system

Front 17

Describe the following terms..
1. Antibody
2. Immunoglobulin
3. Antigen
4. Immunogen
5. Hapten

Back 17

Antibody (Ab) - Glycoprotein in serum and tissue fluid secreted by
plasma B cells in response to specific antigen exposure. Five sub-classes:
IgG; IgM; IgA; IgD; IgE
Immunoglobulin (Ig) - often used interchangeably with Ab but should be
a broader concept (eg, L and H chains, mIg)
Antigen (Ag) - a substance or molecule that, when introduced into the
body, triggers the production of an antibody by the immune system.
Immunogen - a substance or molecule that, when introduced into the
body, is able to induce a humoral and/or cell-mediated immune response
Hapten - low MW substances not immunogenic by itself but become
immunogenic when coupled to a larger carrier molecule

Front 18

What are the four components of immunoglobulins?

Back 18

a- Two light (L) polypeptide chains
b- Two heavy (H) polypeptide chains

Front 19

1. How are the four chains of Immunoglobulins linked?
2. What is the terminal portion of the L chain?
3. H chain?
4. Carboxyle terminal portions?

Back 19

The four chains are linked by disulfide bonds
Terminal portion of L-chain contains part of antigen binding site
H-chains are distinct for each of the five immunoglobulins
Terminal portion of H-chain participate in antigen binding site
The other (Carboxyl) terminal portion forms Fc fragment

Front 20

Describe the following:
1. Isotype
2. Idiotype
3. Allotype
4. Subclass
5. Epitope
6. Paratope

Back 20

a) Isotypes: Antigenic difference in C-region; five Ig classes are different
isotypes.
b) Idiotypes: Agtigenic difference in V-region of Ig.
c) Allotypes: Antigenic feature of Ig that vary among individual under
genetic control. Its difference in C-region of H or L chain.
d) Subclass: Subcategory of each Isotype; Similar between their Fc
regions, but the hinge regions are relatively different (eg, 4 IgG
subclasses in human).
e) Epitope: Tntigenic determinant, is the part of an antigen that is
recognized by antibodies.
f) Paratope: The part of an antibody that recognizes the epitope.

Front 21

Antibody fragments
1. Fab fragment includes what?
2. Fc (crystallizable fragement)
a, b, c, d, e

Back 21

 Fab fragment: include antigen binding site
 Fc fragment (crystallizable fragment):
a- Complement fixation (IgM and IgG)
b- Opsonization (IgG)
c- Placental attachment (IgG)
d- Mucosal attachment (IgA)
e- Binding to mast cells (IgE)

Front 22

What 2 antibodies are similiar in structure?

Back 22

IgG and IgD. Mostly in circular response.

Front 23

IgE - how many fragments are there?

Back 23

3 Fc fragments which is makes it different from the others. IgE is longer and is related to the function, which is against parasitic infections

Least common serum Ig Binds to
basophils and mast cells (Does not
require Ag binding)
Allergic and hypersensitivity reactions
Against parasitic infections (Helminths)
Binds to Fc receptor on eosinophils
Does not fix complement

Front 24

IgA

Back 24

Mostly abundant in oral cavity and secreted in saliva. Very crucial in oral immunity.
-much larger than IgG, IgD, IgE.
-Unique sturcture - 2 single units that is linked by adjoining domain. In addition of a disulfide bond you have a joint to connect 2 single units together.
Found in serum and body secretion:
Tears, saliva, gastric and pulmonary secretions.
Major secretory Ig on mucous surfaces:
coating bacteria or viruses preventing their
adherence.
Does not fix complement (unless
aggregated)
Also present in colostrum and mother
milk: protect new born.

Front 25

IgM

Back 25

Hepamer of 5 IgE linked by disulfide bonds. Initial secretion of humoral response and happens in early stages.
First Ig made by fetus and B
cells
Present in colostrum and
mother milk protect new
born.
Fixes complement

Front 26

IgG

Back 26

Major serum Ig
Major Ig in extravascular spaces
The only Placental transfer Ig
Fixes complement
Phagocytes - opsonization

Front 27

IgD

Back 27

Present in very small amount
in serum
B cell surface Ig
Does not bind complement

Front 28

Primary antibody response

Back 28

-first response to antigen
-Lag period: days or weeks (slow onset)
-Small amount of IgG (low Ab level with gradual increase)
-Ab persist for short duration (weeks then decline rapidly)
-Antibody is IgM

Front 29

Secondary antibody resonse

Back 29

-Subsequent exposure
-Lag period: hours (rapid onset)
-Large amt of Ig (high Ab with rapid increase)
-Persist for long periods (months or years)
-Antibody is IgG