hour 3 imunity

7/30/2019 Hour 3 Imunity

1/54

CHAPTER 21

~IMMUNITY~


2/54

Different antibody molecules may combine with single

antigen


3/54


4/54

21.2 DEVELOPMENT OF IMMUNITY :

PRIMARY AND SECONDARY

RESPONSE


5/54

At the end of this topic, students should be

able to:-

Explain the primary and secondary

immune response Explain the concept of self and non-self


6/54

IMMUNE RESPONSE

1) PRIMARY IMMUNE RESPONSE

2) SECONDARY IMMUNE RESPONSE


7/54

IMMUNE RESPONSE

Primary:

First time exposureto certain antigen

Secondary:

Second exposure to same antigen


8/54

PRIMARY IMMUNE RESPONSE

Results from 1st exposureof B cell to an antigen

Includes series ofcell

division, differentiation,antibody production.

IgM&IgD antibodies:

receptors on surface of B-cell


9/54


10/54


Before stimulation by an antigen, B cells are smalllymphocytes.

After activation, B cell undergo a series of divisions

to produce large lymphocytes. Some enlarge cells become plasma cells

Produce antibodies

Others revert back to small lymphocytes become

memory B cells.


11/54


12/54

Low [antibodies]

produced at early

stagepeak up weeks

after exposure



13/54

Has lag time: slowreaction

3-6 days after the

exposure B cells specific

for that antigen

multiply,develop

plasma cells


14/54

Plasma cells

secrete antibody

antibody

concentrationrise

reach the

peaks 10-12days


15/54


IgM is the first antibody produced Later other classes of antibodies are produced as well

Takes 3-14 days to produce enough antibodies

To be effective against antigen


16/54


Meantime, individual usually develops diseasesymptoms because the antigen has had time to

cause tissue damage


17/54


Primary response

lasts several days

or weeks

[antibodies] plasma cell die

memory B cell

left in the body


18/54

SECONDARY IMMUNE

RESPONSE

The response of

immune system to

the second

infection for sameantigen.

Memory cell

recognize the sameantigen faster.


19/54

Within hours after second exposure:

B memory cell proliferate & differentiate

rapidly into

plasma cell

produce antibody

IgGmainly antibody produced


20/54

Within 2-3 days, antibody rises steeply

Higher than in primary response

Remain high for weeks to month Plasma cells functioning for much longer than

in primary cell


21/54

Memory B cell able to recognize antigen forlonger period

May persist for many years and probably for

life

SECONDARY IMMUNE

RESPONSE


22/54


23/54


24/54


25/54

VACCINATION

Process: vaccination

Antigen : vaccine

Some parts of the microorganism or

A dead microorganism or

A live, altered microorganism.


26/54

VACCINATION

DEF:

Injecting small amounts of antigen, vaccine

into the body To stimulates the immune system

to manufacture antibodies

Without disease symptoms do not cause illness


27/54

VACCINATION

Active artificial immunity acquiring adaptive

immunity

Common vaccinations :-

- BCG

- Rubella

- Hepatitis

- Triple antigen


28/54

Widely used vaccination in the world.

Made of a live, weakened strain of

Mycobacterium tuberculosis.

Disease: Tuberculosis (TB)

Weight loss, cough

Sputum may contain blood

BCG (Bacille Calmatte Guerin)


29/54

In older children & adults

Made of living attenuated virus

Disease: German measles (Rubella)

Affects respiratory passage, lymph nodes in neck,

eyes, skin

Causes complication in pregnancy

miscarriages, stillbirth or

birth defect in unborn babies

eg: blindness, deafness

Rubella


30/54

A serious liver disease caused by viruses

Eg: hepatitis B

Flu-like symptoms

Jaundice, nausea

Severe loss of appetite

Vaccination: genetically engineered (new vaccine)

Hepatitis


31/54

New vaccines :

Modern techniques of molecular biology +

genetic engineering

Antigen made of protein coded by gene

Gene of antigen transferred into bacterium bacterium as a factory producing large

quantities of antigen for use in vaccine


32/54

Will be learn later in the last chapter

RECOMBINANT DNA TECHNOLOGY


33/54

Triple Antigen

(Diphtheria, Pertussis and Tetanus Vaccine

DPT)

Disease : Diphtheria

very contagious and life-threatening bacterial disease

usually attack the throat and nose vaccination: toxoid


34/54

Toxoid:

toxins produced by tetanus and diphtheria

bacteria are detoxified with formaldehyde,

yet their antigen properties remain.


35/54

Disease: Pertussiscommonly known as whooping cough

cause by Bordetella pertussis rod shape, Gram -ve

mainly in young children

vaccination: killed bacteria

extremely contagious disease

may affect the brain severe coughing bouts with 'whoop' sound


36/54

Disease: Tetanus

caused by a Clostridium tetani

rod shape, Gram +ve

enter the body through a cut, wound or anybreak in the skin

causes serious, painful spasms of all

muscles and can lead to locking of the jawVaccination: toxoid


37/54

SELF & NON-SELF

CONCEPT


38/54

ANTIGEN: any foreign substances that elicits an

immune response

All cells posses ANTIGEN in their cell surface

membrane

- acts as markers

- enables cells to recognize each other

own antigens : self

foreign antigens : non-self

ANTIGEN RECALL!!ANTI GE N R E CALL !!


39/54

SELF & NON-SELF CONCEPT

MHC:

In human, referred to as HLA

Human leukocyte antigen

Immune system can distinguish between self-

cells and foreign cells because of they are both

marked with HLAs.


40/54


MHC

(group of

glycoprotein)

= HLA = Self-markers


41/54

IMMUNE SYSTEM DOES NOT RESPOND TO

'SELF' ANTIGENS

Lymphocytes do not attack tissues that carry a

self-marker.

Non-self : pathogens & cells from other

individuals of the same species.

Stimulates immune response.

41



42/54

42


eg. organ transplant


43/54

Very rare for 2 individuals to have same set

HLA genes

except identical twins

The closer the relationship between 2

individuals, the greater the like hood ofsharing the same HLA genes

43

ORGAN TRANSPLANT


44/54

Immune Rejection:

cells transferred from one person to another

can be attacked by immune defenses

Host's immune system recognizes the foreign

tissue as non-self

T-cells attack the transplanted tissue and destroy it

**Humoral or cell-mediated response? Answer??

complicates transplant of tissues or organs

44

ORGAN TRANSPLANT


45/54

1. Tissue compability test

Before transplant

Tissue from donors must match the host's tissue

Increase the chances of successful

transplantation

Tissue matching:

> close relatives

< non-relatives

45

Prevention of Graft rejection


46/54

2. Exposure of bone marrow and lymph tissue to

radiation by X-rays

Inhibit production of lymphocytes

Slows down rejection

But may cause:

Unpleasant side-effects Increased risk of infection during treatment

46



47/54

3. Immunosuppression

Certain drugs used to suppress the immune

system

graft rejection delayed

But patients becomes:

Suseptible to all kind of infections

More prone to develop cancer

47



48/54

4. Suppress the killer T-cells

Cell responsible for rejection

Can overcome the problem of radiation and

immunosuppression

Patient treat with monoclonal antibodies that

recognize and destroy the killer T cells

48



49/54



50/54

First exposure to an antigenstimulates a primary

response

First exposure to an antigenstimulates a primary

response

Infection causes specific

antibodies to appear in the

blood plasma in 3 to 14 days

Infection causes specific

antibodies to appear in the

blood plasma in 3 to 14 days

Time is taken for B-cell and T-

cell to proliferate

Time is taken for B-cell and T-

cell to proliferate



51/54

Second exposure to the

same antigen stimulates a

second response.

Second exposure to the

same antigen stimulates a

second response.

More memory B-cellproduce more plasma cell

More memory B-cellproduce more plasma cell

More antibodies are

produced

More antibodies are

produced

The response is

more rapid

The response is

more rapid

SECONDARY IMMUNE RESPONSE


52/54

BCGBCG

RubellaRubellaRubellaRubella

HepatitisHepatitis

TripleTripleantigenantigenTripleTripleantigenantigen

VACCINATION FOR HEALTH


53/54


54/54

21.3 Immune disorder: AIDS

hour 3 imunity

Documents