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CHAPTER 1 Introduction to immunology

Learning outcome

Definition and concept of immunology

Basic terminologies in immunology

The study of our protection from foreignmacromolecules or invading organisms (immunity) and

how do we response to them (defense mechanisms).

Two types of immune response:

i. non-specific (innate) immune systems

a. First line defense

b. Non-specific

ii. specific (adaptive) immune systems

a. Second line defense

b. Specific

Review Question

1. Brief history in immunology

i) China (960 1280 A.D.) variolation (deliberate

inoculation with smallpox).

ii) Edward Jenner, 1798 immunization against

smallpox using cowpox material.

iii) Louis Pasteur (1870s) origin of the term

vaccination any type of protective inoculation.

vacca = cow

2. Differences between innate & adaptive immunity

Innate Adaptive

Characteristics

Rapid response (mins)

Not antigen specific

No memory Some cellular

components may help

specific immunity

Short term memory &

not effective

Slow response (days)

Antigen specific

Memory Some of its products

may help non-

specific immunity

Long term memory

& more effective

Immunecomponents

Skin,

Complements,

NK cells,

macrophages,

neutrophils

B and T cells,

secreted molecules

(antibody)

3. Examples of innate immunity components cells of innate,

barriers, processes etc.

i. Cell of innate immune response

a) Leukocytes (WBC)i) Natural kil ler (NK) cells

Attack host cells infected by microbes , but do

not directly attack invading microbes.

(1) Attack & destroy tumor cells & virallyinfected cells.

(2) NK cells are armed with granules filled withpotent chemicals.

(3) But while killer T cells look for antigen

fragments bound to self -MHC molecules, NK

cells recognize cells lacking self-MHC

molecules.

ii) Mast cells

iii) Eosinophils

(1) Secrete highly toxic proteins & free radicals

effective in killing bacteria & parasites.

(2) Responsible for tissue damage occurringduring allergic reactions.

iv) Basophils

(1) Release histamine when activated.

(2) Important in defense against parasites & in

allergic reactions (asthma).

b) Phagocytic cellsi) Macrophages

ii) Neutrophils

iii) Dendritic cells

c) Complement Systemi) Consists of > 20 serum glycoproteins.

ii) Components circulate in the serum as proenzymes

(The inactive or nearly inactive precursor of an

enzyme, converted into an active enzyme by

proteolysis).

iii) Important in inflammation & opsonization.

iv) 3 pathways: classical, lectin & alternative.

ii. Barriers

a. Physical & mechanicali. Tears, saliva & urine - Flushing action protects

surfaces from colonization.

ii. Mucous membranes - Entraps foreign

microorganisms; Cilia propel microorganism

mechanically.

b. Chemicali. Skin - Prevent entry of microbes; Acidic (pH 3-5)

retards growth of microbes

ii. Low pH - Acidity of stomach content

iii. Chemical mediators

Lysozyme cleaves bacterial cell wall

Interferon inhibit viral replication

Transferrin & lactoferrin deprive m/orgm


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c. Phagocytic/Endocytici. Various cells internalize (endocytose) & break

down foreign macromolecules.

ii. Cells (monocytes, neutrophils, macrophages)

internalize (phagocytose), kill & digest whole

microorganism.

d. Inflammatoryi. Tissue damage & infection induce leakage of

vascular fluid & influx of phagocytic cells into the

affected area.

ii. Phagocytes (neutrophils) release factors that

summon other leukocytes & lymphocytes.

iii. 5 Signs of Inflammation: Redness, Swelling, Heat,Pain, Loss of function.

iii. Processes

i. Phagocytosisa. The engulfment & digestion of foreign

particles by phagocytes.

b. The cell membrane invaginates to capturethe particle then forming a sac or vacuole.

(ada gambar dlm notes)

4. Recognition of self & non-self how?

By using antibody!

Soluble proteins produced by lymphoid tissues in response

to an antigen. Ab contains a receptor that specifically binds

to one Ag.

Recognition distinguish self from non-self

Response

Effector

Memory

5. Inflammation association with vasodilation; signs

Tissue damage & infection induce leakage of vascular fluid

& influx of phagocytic cells into the affected area.

Phagocytes (neutrophils) release factors that summon other

leukocytes & lymphocytes.

5 Signs of Inflammation: Redness, Swelling, Heat, Pain, Loss

of function.

6. Components of adaptive immune response

Humoral immunity

- Production of Ab by B lymphocytes (B cells).

- Defense against extracellular microbes.

Cell-mediated immunity

- Mediated by T lymphocytes (T cells).

- Defense against intracellular microbes.

Principal cells:

- Lymphocytes- B & T cells- Antigen-presenting cells (APC) dendritic cells.

- Effector cells activated T lymphocytes,

mononuclear phagocytes

7. Characteristics of adaptive immunity

Specific & diverse - Enables immune system to respond

specifically to large variety of Ag.

Memory - Enhanced responses to repeated exposures to the

same Ag.

Specialization - Optimal defense against different types of

microbes (humoral & cell-mediated immunity different

classes of microbes).

Nonreactivity to self - Prevents injury to the host during

responses to foreign Ag.

8. Overview of the basic arms of immunology

Immune response:

i. non-specific (innate) immune systems

a. First line defense

b. Non-specific

ii. specific (adaptive) immune systems

a. Second line defense

b. Specific

(same as above just trangkan laaa yeeeerrr)

9. Cells involved in immune surveillance.

- Natural killer (NK) cells

- Lymphocytes- B & T cells- Antigen-presenting cells (APC) dendritic cells.

- Effector cells activated T lymphocytes, mononuclear

phagocytes


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CHAPTER 3 Antigens

Learning Outcome

Define & distinguish the characteristics of immunogen,

antigen & haptens

Antigen - molecule that sometimes stimulates an

immune response. Specifically bound by Ab @ T cell

receptor (TCR).

Immunogen - an Ag that induces immune response.Not all Ags are immunogens; e.g. small molecular

weight molecules may not stimulate immune response

unless linked to macromolecules.

Hapten - A small molecule which could never induce

an immune response on their own but can become

immunogenic if joined to a carrier molecule (usually

protein).

Describe the factors influencing immunogenicity

Describe types of antigens

Review Questions

1. What differentiate antigens from own cells?

2. Epitopes = antigenic determinants; what are they

actually?

Antibody which binds to b-cell

3. Extracellular vs. intracellular antigens: which immune

components can recognize those antigens?

4. Why do some antigens need to be processed &

presented?

5. What presents antigens?

6. Difference between antigen, immunogen, allergen.

7. Terminologies: hapten, carrier etc.

8. Features/characteristics of antigens e.g. size, dose etc

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