Introduction: Basic concepts

Question 1

Inappropriate response:

Answer 1

Sepsis - overreaction
Allergy and asthma – oversensitive
Chronic inflammatory disorders – no resolution

Question 2

Autoimmune diseases:

Answer 2

diabetes type I, multiple sclerosis,
rheumatoid arthritis, systemic lupus erythematousus

Question 3

Immunodeficiencies:

Answer 3

Primary (genetic) (Severe Combined Immunodeficiency)
Secondary/acquired (AIDS, resulting from HIV infection)

Question 4

Innate immune system:

Question 5

Adaptive immune system:

Question 6

Primary lymphoid organs:

Answer 6

generation of leukocytes (bone- marrow), and maturation of lymphocytes – B-cells in the marrow, T-cells in the thymus.
When mature, they leave the primary organs and circulate in the blood and the lymphatic system.

Question 7

Secondary lymphoid organs:

Answer 7

where mature (but naïve) lymphocytes meet antigens and the adaptive immune response develops

Question 8

Primary organs:

Answer 8

• Bone marrow
• Thymus gland

Question 9

Secondary organs:

Answer 9

• Spleen (filter blood)
• Lymph nodes (filter lymph)
• MALT = mucosa associated tissue: Peyer`s patches, tonsils, appendix

Question 10

hematopoietic stem cells

Answer 10

Within the bone marrow, HSCs are constantly renewed and directed to differentiate into two major types of progenitor cells

Question 11

Important first line defence:

Answer 11

Express granules containing proteases, antimicrobial proteins++

Question 12

Neutrophils

Answer 12

phagocytic and bactericidal, first at the site of infection but short-lived

Question 13

Basophils/mast cells

Answer 13

inflammation/allergies

Question 14

Eosinophils

Answer 14

kill antibody coated parasites

Question 15

Myeloid cells I:

Answer 15

Granulocytes

Question 16

Myeloid cells II:

Answer 16

Monocytes and Macrophages

Question 17

Blood Monocytes

Answer 17

migrate into the tissues (cytokine exposure) and differentiate into Macrophages
Arrive later at site of infection than neutrophils and live longer

Question 18

Dendritic cells

Answer 18

Heterogenous: arise both from myeloid and lymphoid (monocytes can differentiate to DCs)
Phagocytic, professional antigen-presenting cells
In tissues, the DCs monitor the environment for signs of invasion by pathogens the skin (Langerhans cells) and the mucosal lining (nose, lungs, stomach, intestines)
Upon infection: Capture and process antigens, migrate to lymph nodes to present antigens to T-cells.
Links innate and adaptive immunity

Question 19

T cells (adaptive)

Answer 19

• Developing in the thymus: clonal selection
• Express rearranged T-cell receptor (TCR)

Question 20

T-cell Effector cells:

Answer 20

T helper cells (CD4+, different sub-
types), T cytotoxic cells (CD8+), memory cells

Question 21

B cells (adaptive)

Answer 21

• Express rearranged B cell receptors (BCR)
• Antigen-presenting cells

Question 22

B cells effector cells:

Answer 22

plasma cells that release antibodies,
memory cells

Question 23

Secondary lymphoid organs: effector responses

Answer 23

Areas where lymphocytes encounter antigens, become activated, undergo clonal expansion, and differentiate into effector cells and memory cells

Question 24

Innate immune cells: pattern recognition

Answer 24

Innate immune cells have germ-line encoded pattern-recognition receptors that recognise conserved microbial patterns and damaged/erroneous self

Question 25

PRRs signal to activate the cell and initiate
effector functions:

Answer 25

phagocytosis (some cells)
* secretion of cytokines (activate nearby cells and
tissues) and chemokines (attracts other cells) and
antimicrobials
* inflammatory response

Question 26

Adaptive immune cells: Clonal expansion

Answer 26

daptive immune cells (T, B) have highly specific receptors that recognise antigens
Receptors are generated through gene- rearrangements to create diversity
The B-cell receptor is an antibody that can recognise antigens directly
The T-cell receptor recognises processed antigens presented on MHC by other cells
Activated B- and T-cells clonally expand and mature to become effector cells