hour 1 imunity

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CHAPTER 21

~IMMUNITY~


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CHAPTER 20 : COORDINATION

SUBTOPIC 20.4 : HORMONES IN PLANTS

State the roles of hormones in plants:-o auxino gibberellino cytokinino abscisic acido ethylene

Explain the role of phytochrome in

the regulation of flowering


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21.1 Immune Response

21.2 Development of Immunityprimary and secondary

response

21.3 Immune Disorder- AIDS


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21.1 IMMUNE RESPONSE

# Immunity# Classes of antibody

# Humoral and cellmediated immune

response


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INTRODUCTION

Immune system is our internal defend

system, protects the body against

disease-causing organism and certain

toxins.

Disease-causing organism or pathogensincludes certain viruses, bacteria, fungi

and protozoa.


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IMMUNITY

Defined by Sir Macfarlane Burnet:

The capacity to recognize the intrusion of

material foreign to the body & to mobilize

cells & cell products to help remove that

particular sort of foreign material with

greater speed & effectiveness

(Biological Science, pg. 485)


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Pathogens(such as bacteria,fungi, and viruses)

INNATE IMMUNITY(all animals)

Rapid response

Recognition of traits sharedby broad ranges ofpathogens, using a smallset of receptors

Recognition of traitsspecific to particularpathogens, using a vastarray of receptors

Slower response

Barrier defenses:

SkinMucous membranesSecretions

Internal defenses:

Phagocytic cellsNatural killer cellsAntimicrobial proteinsInflammatory response

Humoral response:

Antibodies defend againstinfection in body fluids.

Cell-mediated response:

Cytotoxic cells defendagainst infection in body cells.

ADAPTIVE IMMUNITY

(vertebrates only)


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ANTIBODY A protein secreted by plasma cells

(differentiated B cells) that binds to a

particular antigen.

Antibody also called immunoglobulin(Ig).


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o Y shaped

o 4 polypeptide chains:-

2 light chains

2 heavy chains

o Linked by disulfide bridge

o Variable and constantsegments

o V portion is the antigen

binding site


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1)1) IgMIgM Primary antibodyresponse.

CLASSES OF ANTIBODY

2)2) IgAIgA Secretory; saliva

& tears.


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5) IgG Temporary

protection to newborn.

3)3) IgEIgE Allergic response.

4)4) IgDIgD Cell surface receptorsin B lymphocytes.


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TERMS TO REMEMBER!

Helper T

Cells

(TH)

Cytotoxic T Cells

(TC)

Interleu

kin (IL)

MHC

Proteins


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HELPER T CELLS (TH)

Helper T cells (TH cells) are a subset of

T-cells that usually express the CD4co-receptor and have a major role in

controlling and regulating the immune

system by providing help to otherwhite blood cells.


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CYTOTOXIC T CELLS (TC)

Cytotoxic T

lymphocytes (CTLs)

are a subset of T-

cells that usuallyexpress the CD8 co-

receptor and have

the ability todirectly kill infected

cells.


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INTERLEUKIN (IL)

Any of a class of naturally occurring proteins

important in regulation of lymphocyte

function.

Antigens and microbes stimulate production

of interleukins.

Interleukin induce production of various types

of lymphocytes that ensure a plentiful supply

of T cells that fight specific infectious agents.


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MHC PROTEINS

Major Histocompatibility Complex

Our cells are dotted withprotein molecules

(self-antigens) that are not antigenic.

MHC proteins, a set of closely-linked genes.

Code for a set of cell-surface proteinscalled MHC molecules.


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When a macrophage ingest a pathogen,omost of bacterial antigen are destroyed

by its enzyme

osome fragments of the foreign antigen

will bind with MHC proteins on the

macrophages surface

othe macrophage becomes Antigen-

presenting cell (APC)


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TYPES OF IMMUNE

RESPONSE

1) Humoral Immune Response

2) Cell Mediated Response


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HUMORAL IMMUNE

RESPONSE

B lymphocytes.

Release antibodies into the bloodplasma, tissue fluid and lymph.

Defend against pathogens & toxins in

extracellular fluids.


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CELL MEDIATEDCELL MEDIATED

IMMUNE RESPONSEIMMUNE RESPONSE

T lymphocytes

T cells DO NOT release antibodies.

T cells attack the following:-

cells that have become infected by a

microorganism, especially virus

transplanted organs and tissues

cancer-causing cells

HUMORAL CELL MEDIATED


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HUMORAL

IMMUNE RESPONSE

CELL MEDIATED

IMMUNE RESPONSE

1) Pathogens bearing foreign antigen invades body

2) APC (macrophage) phagocytizes pathogen

3) Foreign antigen-MHC complex displayed on

APC surface

4) TH cell binds with foreign antigen-MHC Complex

5) APC releases IL-1 to activate TH cell

6) TH cell proliferate producing activated TH cells and

memory TH cells



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HUMORAL

IMMUNE RESPONSE

CELL MEDIATED

IMMUNE RESPONSE

7) B cell that has interacted

with foreign antigen will

display foreign Ag-MHC

complex

7) TC cell with a receptor

that fits the antigen

displayed by an APC binds

with the TH

cell receptor

8) An activated TH

cell

bearing receptors specific

for the displayed antigen

binds to the B cell

8) TH

cell will release IL-2

and the TC

cell is activated



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HUMORAL

IMMUNE RESPONSE

CELL MEDIATED

IMMUNE RESPONSE

9) TH

cell will release IL-2

and the B cell is

activated

9) IL-2 secreted by the TH

cell stimulate TC

cells to

divide mitotically

10)IL-2 secreted by thehelper T cell stimulate B

cells to divide

mitotically

10)Forming clones ofidentical T

Ccells

11)Forming clones of

identical B cells

11)Differentiate into active

TC cell and memory TC

cell



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HUMORAL

IMMUNE RESPONSE

CELL MEDIATED

IMMUNE RESPONSE

12)Differentiate into plasma

cells and memory B cells

-

13)Plasma cells secreteantigen

-

14)Antibody Antigen

interaction occurs

-

15)Triggers processes leading

to pathogen

destruction

-


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1. Immune system is our internal defend system,

protect the body against disease-causing

organism and certain toxins.2. There are five classes of antibodies : IgG, IgA,

IgM, IgE and IgD.

3. There are two types of immune response :humoral and cell mediated immune response.


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21.1 IMMUNE RESPONSE

# Roles of lymphoid organs

# Antigen-antibody

interactions

hour 1 imunity

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