Immune System Overview

Question 1

What are the different categories of leukocytes and list examples for each

Answer 1

granulocytes: neutrophils, eosinophils, basophils
agranulocytes: lymphocytes, monocytes

Question 2

Where are leukocytes derived from and what are the cells involved called?

Answer 2

derived in bone cells from hematopoietic stem cells

Question 3

what is process called where immune cells move from blood through tissues?

Answer 3

chemotaxis

Question 4

what direction do immune cells travel in chemotaxis and why?

Answer 4

travel towards highest concentration of chemoattractants to fix injury/fight off pathogen

Question 5

What is the process called when the resident macrophage sends a chemical signal to attract leukocytes?

Answer 5

leukocytosis

Question 6

describe key characteristics of each of the granulocytes

Answer 6

neutrophil: most abundant, bacterial infection sites to kill
eosinophil: attack parasitic worms, asthma/allergy
basophil: histamine, vasodilation, attract other immune cells

Question 7

describe key characteristics of agranulocytes

Answer 7

lymphocytes: assoc lymphoid tissue
monocytes: largest, leave bloodstream and become macrophages or dendritic cells

Question 8

What receptors recognise own cells against foreign cells?

Answer 8

pattern recognition receptors (PRR)

Question 9

what is the name of the specialised PRR that recognises different signs of pathogens and triggers the immune system to respond

Answer 9

toll like receptor (TLR)

Question 10

what occurs once TLRs activated?

Answer 10

release of antiviral/proinflam cytokines/chemokines via inflam cascade

Question 11

what immune cells conduct phagocytosis?

Answer 11

neutrophils and monocytes

Question 12

describe the second process needed if phagocytosis does not effectively kill the pathogen

Answer 12

respiratory burst occurs where the neutrophil/monocyte consumes O2 to make destructive free radicals, killing the bacteria and itself simultaneously

Question 13

what cell stimulates respiratory burst?

Answer 13

t helper cell

Question 14

what is the main response to pyrogens and what cells can send them to the brain to initiate this outcome?

Answer 14

leukocytes and macrophages can send pyrogens to the brain to initiate fever

Question 15

describe function of MHC proteins

Answer 15

let immune cells know if cells are foreign (to be targeted and killed) or self

Question 16

how do MHC proteins hold identification peptides

Answer 16

deep groove

Question 17

describe the diff MHC classes

Answer 17

class 1: appears on all self cells
class 2: on specific immune cells (foreign)

Question 18

natural killer cells are a specialised type of what immune cell?

Answer 18

lymphocyte

Question 19

describe functions of natural killer cells

Answer 19

kill cancer and viral infections by detecting non-specific cellular anomalies eg lack of self MHC

Question 20

how do natural killer cells kill cells?

Answer 20

by inducing cytotoxic effects -> apoptosis, secrete potent inflammatory chemicals

Question 21

differentiate between T cells and B cells

Answer 21

T cells born in bone marrow, go to thymus to mature and train then rejoin circulation and reside in secondary lymphoid tissue
B cells: made in bone marrow and mature there, join circ and go to secondary lymphoid tissue

Question 22

what process in initiated once T/B cells activated?

Answer 22

clonal expansion

Question 23

differentiate between humeral and cellular immunity

Answer 23

humeral: antibodies kill things (B cells)
cellular: cell kills things (T cells)

Question 24

describe the training of T cells

Answer 24

1) immunocompetence- gain ability to recognise specific antigen by binding to it
2) self-tolerance- unresponsive to self-antigens

Question 25

where are naive B/T cells exported to?

Answer 25

secondary lymphoid organs

Question 26

what are most common places for first encounter bw immunocomp naive cell and antigen and what occurs?

Answer 26

lymph node or spleen, cell binds to receptor -> clonal expansion

Question 27

what occurs once clonal expansion initiated?

Answer 27

proliferation and differentiation, most clones are effector T/B cells, some are memory

Question 28

what type of cells are effector B cells and how many ABs can they secrete /second?

Answer 28

plasma cells, secrete 2000 AB molecules/s

Question 29

what is achieved by memory B cells

Answer 29

immunological memory

Question 30

list two key classes of T cells

Answer 30

CD4: T helper cells CD8: cytotoxic T cells (respond to infection by binding)