lecture 1 immunology (week 2)

Question 1

what process are macrophages involved in?

Answer 1

phagocytosis

Question 2

what processes are nuetrophils involved in?

Answer 2

phagocytosis and degranulation

Question 3

what do dendritic cells do?

Answer 3

present antigens

Question 4

what do natural killer cells do?

Answer 4

they are targeted cell killers

Question 5

describe neutrophils

Answer 5

contain granules and enzyme pathways that assist in the elimination of pathogenic microbes

40-70% of all white blood cells

multilobulated nucleus

life span between 5-135 hours

Question 6

what is phagocytosis?

Answer 6

the engulfment of microbes and then the killing through multiple bactericidal pathways

Question 7

describe macrophages?

Answer 7

they are sentinel cells that respond to tissue injury and pathogen invasion

in most tissue

highly plastic cells

different functions in response to changes in the environment

Question 8

what is neutropenia?

Answer 8

condition that causes a low number of white blood cells in your blood –> higher susceptibility infection

Question 9

where do phagocytes go?

Answer 9

tissue macrophage senses infection –> recruit immune cells via chemokines and cytokines –> neutrophils are rapidly released from the bone marrow into the circulation and migrate to the infection site –> monocytes infiltrate into tissues, differentiate to macrophages, remove deal cells for tissue repair

recognition –> reaction –> resolution

Question 10

how are neutrophils recruited?

Answer 10

sense and respond to soluble inflammatory signals

regulated through adhesion molecules (selectins, cadherins, and integrins) between leukocytes and the inflamed endothelium, and are followed by extravasation into local tissues via chemotaxis

The classical neutrophil recruitment cascade comprises -
capturing (tethering), rolling, slow rolling, arrest, transmigration

Question 11

describe the steps in phagocytosis

Answer 11

recognition –> ingestion and formation of phagosome –> formation of phagolysosome –> microbial killing and formation of residual body –> elimination or exocytosis

Question 12

describe the process of recognition

Answer 12

innate immune cells recognise pamps through prrs

tlrs play a central role in host cell recognition and responses to microbial pathogens - not phagocytic receptors, cooperate with phagocytic receptors to make phagocytosis more efficient

receptors that directly bind pamps induce phagocytosis include glucan receptors (dectin-1) and mannose receptor

Question 13

describe the process of recognition