Introduction to Immunology

Question 1

Define an Antigen (Ag)

Answer 1

Any substance that is recognised as foreign by the immune system so provokes an immune response.

Question 2

What are the two important characteristics of antigens?

Answer 2

Immunogenicity - ability to provoke an immune response

Reactivity - ability to react with antibodies or T cells

Question 3

Where are the primary organs where immune cells are formed or matured?

Answer 3

Bone marrow and Thymus

Question 4

Where are the secondary organs where immune cells work?

Answer 4

Lymphatic system and Spleen

Question 5

What are the cells of the immune system?

Answer 5

Natural Immunity
1. Granulocytes (neutrophils, eosinophils, basophils)
2. Monocytes - that enter tissues and referred to as
macrophage
3. Natural killer cells

Specific Immunity
- T lymphocytes
- B lymphocytes

Question 6

What are the two arms of adaptive immunity?

Answer 6

Humoral and Cell-mediated

Question 7

Humoral Immunity

Answer 7

involved in production of antibiotics by activated B cells

Question 8

Cell mediated immunity

Answer 8

involves activated T cells

1. Cytotoxic T cells - help to kill infected host cells
2. Helper T cells - via production of cytokines
   help promote:
   - antibody production of B cells
   - activating macrophages to kill intracellular pathogens

Question 9

What are the two types of Immunity

Answer 9

innate and adaptive

Question 10

Innate Immunity

Answer 10

consists of the components already at the location of the infection and respond immediately with a generalised response.

e.g, epithelial barriers, anti-microbial peptides, phagocytes, complement
system, acute phase reactants, and natural killer (NK) cells

Question 11

Adaptive (specific) Immunity

Answer 11

involves specialised T and B cells that are waiting in sites away from the infection - when activated launch a specialised system that fights the specific invading pathogen.

Takes longer to recognise pathogen

B cells produce antibodies, while T cells can be either killer (cytotoxic), helper or suppressor

Question 12

What are cytokines?

Answer 12

Immunological hormones

Question 13

What is the role of cytokines?

Answer 13

stimulate the immune system
activate inflammatory cells
stimulate production of different blood types in the bone marrow
antiviral activity
Inhibit certain cell types, e.g. tumours

Question 14

Define Active Immunity

Answer 14

Immunity as a consequence of contact with an
antigen via a disease or vaccine

Question 15

Define Passive Immunity

Answer 15

Immunity donated from another individual e.g. mother to fetus

Question 16

What are the properties of specific immunity?

Answer 16

Recognition - of the foreign antigen
Response - for its elimination provoked by antigens
Remembers - immunological memory
Regulation - once infection load reduced the immune
response diminishes

Question 17

What is haematopoiesis?

Answer 17

Formation of the cellular components of blood

Question 18

What are the properties that govern the outcome of the hostpathogen interactions?

Answer 18

Host:
- Genes regulating immune responses
- Health of the host

Pathogen:
- Mechanisms of pathogenicity
- Immune escape mechanisms
- Number of pathogens