Immunology: Microbial Pathogen Recognition And Elimination

Front 1

Describe the basis of 'innate immunity'

Back 1

Defences which are present before a pathognenic infection.

These are non specific.

Front 2

What are the components of innate immunity?

Back 2

1. Anatomical barriers

2. Physiological barriers

3. Phagocytic / endocytic barriers

4. Complement

5. Interferons

6. Inflammatory barriers

7. Fever

Front 3

What are the anatomical barriers?

Back 3

1. Skin

2. Mucous membranes

Front 4

What are the physiological barriers?

Back 4

1. Temperature

2. pH (skin pH = 4)

3. Chemical mediators - sweat = salt and lysozyme

Front 5

What are the phagocytic /endocytic barriers?

Back 5

1. Monocytes

2. Neutrophils

Front 6

Describe the stages of neutrophilic attack.

Back 6

1. Chemotaxis towards pathogen

2. Adherence to

3. Ingestion

4. Digestion

5. Elimination

Front 7

What are the complement barriers?

Back 7

1. Opsonins

2. Chemotactic factors

3. trigger of inflammation & fever

4. Membrane attack complex -> lysis

Front 8

What is the role of interferons?

Back 8

Inhibit viral infection.

Front 9

What are the inflammatory barriers?

Back 9

1. Dilation and increased permeability of blood vessels through release of histamine, prostaglandin and leukotricenes

2. Migration of phagocytes

3. Tissue repair

Front 10

How is fever mediated?

What does it enhance the effects of?

Back 10

1. Mediated by Interleukin 1

2. Enhances the effects of interferons and phagocytic activity

Front 11

What are the methods of pathogen recognition?

Back 11

1. Direct recognition

2. Opsonization

Front 12

How does the immune system directly recognise a pathogen?

What receptors are involved in this recognition?

Back 12

Through receptors on the machrophage directly interacting with bacterium cell surface receptors.

1. Scavenger receptors

2. Leptin receptors

Front 13

What is the process of opsonization?

Back 13

Bacterial cells marked for destruction by the immune system

Front 14

What are the key principles of the adaptive immune system?

Back 14

1. Highly specific

2. Acquired

3. Diverse

4. Has a memory

5. Self / non self recognition

Front 15

What are the cells of the immune system?

Back 15

1. B Cells

2. T cells

Front 16

Where do B cells originate?

Describe their structure.

Back 16

Originate in the bone marrow

Antigen binding receptor bound by a membrane.

Front 17

How is a B cell activated?

What processes occur upon its activation?

Back 17

1. Binding of complementary antigen

2. Rapid diffusion and differentiation into:

i) Memory B cells

ii) Plasma cells

Front 18

What is the role of plasma cells?

Back 18

Secrete antibodies.

Front 19

Where do T cells mature?

Back 19

In the thymus

Front 20

What is the unique T cell receptor?

What does it recognise?

Back 20

1. Unique antigen binding molecule - T cell receptor

- Recognises antigens bound to major histocompatibility complexes

Front 21

What is the role of major histocompatibility complexes?

Back 21

Bind peptide fragments from pathogens for displaying to T cells

Front 22

What are the types of T-Cell?

Back 22

1. T Helper cells

2. T cytotoxic (killer)

Front 23

What is the process of T cell activation and differentiation?

Back 23

1. mobilised by binding to MHC - antigen complex

2. MHC - antigen complex activates T cell to release cytokines

3. Cytokines mature T cells

4. Cytokines cause 3 divergin paths of differentiation

i) some become T cells which secrete more cytokines

ii) some become T helper cells which attract macrophages & neutrophils and direct them to pathogens

iii) some become T cytotoxic cells which track down cells infected with viruses.

Front 24

What are the primary organs of the immune system?

What is the general role of each?

Back 24

1. Thymus - Area of T cell maturation.

2. Bone marrow - Area of B cell maturation

3. Lymphatic system - links the primary and secondary lymphoid organs

Front 25

What are the secondary organs of the immune system?

What is the general role of each?

Back 25

1. Lymph nodes - Sites where immune responses are mounted to antigens in lymph

Front 26

What are the different types of antibodies?

Back 26

1. M

2. G

3. A

4. D

5. E

Front 27

Back 27

1. Antigen binding site

2. Heavy chain

3. Light chain

4. Hinge region

5. Disulfide bond

6. Variable region

7. Constant region

Front 28

What are the main categories of defence which an antibody mediates?

Back 28

1. Opsonization

2. Antibody dependent cell mediated cytotoxicity (ADCC)

3. Activation of complement

4. Precipitation (agglutination)

5. Neutralisation

Front 29

What is opsonization?

Back 29

Foreign particles targeted for destruction by phagocytes.

Front 30

What is Antibody dependent cell mediated cytotoxicity (ADCC) ?

Back 30

Antibody binds to virus infected target cells via Fc receptors of Natural killer cells which directs cytotoxic activity to apoptose the infected cell.

Front 31

What is an Fc receptor?

Back 31

An Fc receptor is a type of receptor found on the effector cells of the immune system such as T killer cells or natural killer cells. The Fc receptor will only bind to antibodies which are bound to a pathogen.

Front 32

What is the process of complement activation?

Back 32

IgM and IgG activate a series of glycoproteins - lysis of bacterial cell by perforation of membranes.

Front 33

What is the process of precipitation / agglutination?

Back 33

1. Hinders activity of pathogens

2. Increases chance of phagocytosis

Front 34

What is the process of neutralisation?

Back 34

1. Blocks toxin binding to cells via antigen bindin

2. Blocks bacterial attachment to cells via antigen binding

Front 35

Ultimately what does the extent pathogenicity of microbes depend on?

Back 35

Their ability to evade the immune response.