Immunology - Neutrophils And Their Products - Ch 3

Front 1

What two type of cells are leukocytes derived from?

Back 1

Myeloid (bone marrow) and lymphoid stem cells

Front 2

What are the different types of leukocytes?

Back 2

Granulocytes, monocytes and dendritic cells.

Lymphocytes (B cells, T cells, and NK cells)

Front 3

What percent of leukocytes are neutrophils in carnivores? horses? ruminants?

Back 3

60-75% of leukocytes in Carnivores. 50% in horses, and 20-30% in ruminants.

Front 4

What do the primary granules of neutrophils contain? What about the secondary granules?

Back 4

Primary granules: myeloperoxidase, cathepsin B, and elastase

Secondary granules: lysozyme, collagenase, and lactoferase

Front 5

What two kinds of enzymes are involved in slowing down neutrophils for absorption from the bloodstream? Which one slows neutrophils and which one stops them?

Back 5

Selectins and integrins
Selectins slow the neutrophils. The integrins stop them and help them migrate through.

Front 6

What are the enzyme receptor halves on the neutrophil allowing them to bind to endothelial cells?

Back 6

L-selectin and CD11b/CD18

Front 7

What are the enzyme receptor halves on the endolthelium allowing binding with the neutrophils?

Back 7

P-selectin and ICAM-1

Front 8

What chemoattractant attracts neutrophils?

Back 8

IL-8

Front 9

What interleukin triggers transcription of the enzyme responsible for slowing and drawing in the neutrophils from the endothelium?

Back 9

IL-1. In this way, the response can be localized to where the leukocytes are needed.

Front 10

What are the five steps of neutrophil migration?

Back 10

rolling
adherence
emigration
chemotaxis
inflammatory stimulus

Front 11

What is this a picture of?

Back 11

A neutrophil emigrating through an endothelium.

Front 12

During phagocytosis, what are the chemotaxis agents attracting phagocytes?

Back 12

C5a-complement and chemokines (IL-8)

Front 13

During phagocytosis, what are the agents of adherence? What are their purpose?

Back 13

Opsonins (antibodies and complement C3b)

opsonization - make tastier to eat

The opsonins entice the neutrophils to phagocytose the bacteria by binding to the bacteria and then binding on the other end to the leukocytes.

Front 14

During phagocytosis, what occurs during the ingestion phase?

Back 14

lysosomes (the organelles containing lysozymes) interact with phagosomes (the organelles that contain the phagocytized bacteria) to digest the critter.

Front 15

During phagocytosis, what occurs during the digestion phase?

Back 15

the respiratory burst (where potent oxidants are produced) and then lytic enzymes (with antimicrobial peptides).

The respiratory burst will kill the bacteria, then they will be digested by lytic enzymes.

Front 16

What are the three types of surface receptors of neutrophils?

Back 16

cell adhesion molecules
complement receptors
antibody receptors

you can see the three receptor types – to bring the leukocytes into the cell (p-selectin, integrin), then the ones that seek out the bacteria.

Front 17

What is the mechanism of the respiratory burst pathway?

Back 17

Neutrophils need lots of oxygen to generate oxygen radicals. The consumption of O2 increase 100-fold when stimulated.
So the bacterium binding stimulates NOX, which releases the electrons to make the superoxides which is converted immediately to hydrogen peroxide which is converted quickly to hypochloric acid.

Front 18

which species has less superoxide in the respiratory burst pathway than others?

Back 18

sheep

Front 19

How doe superoxide dismutase and oxygen radicals cause tissue damage?

How do the neutrophils protect themselves?

Back 19

The oxygen radicals and superoxide dismutase are outside of the cells and can cause tissue damage (what happens in arthritis).

The hydrogen peroxide and hypochloric acids can work against the neutrophil as well, but the neutrophil produces lots of glutathione (an antioxidant) to protect it.

Front 20

What are the four antimicrobial molecules?

Back 20

Lytic enzymes (phagolysosomes)
Peptides (defensins)
Lysozymes
Lectins (selectins, collectins, pentraxins)

Front 21

What is the function of lytic enzymes and lysozymes?

Back 21

To destroy bacterial cell walls.

Front 22

What are the main antimicrobial molecules? What is their function?

Back 22

Defensins

The kill bacteria, fungi, and viruses

Front 23

What are examples of lectins (antimicrobial molecules)? How do they function?

Back 23

Selectins, collectins (conglutinin and mannose-binding lectin - MBL), and pentraxins (CRPs - c-reactive proteins and SAPs - serum amyloid P)

They act as opsonins and activate complement.

Front 24

What are babies born without MBL susceptible to?

Back 24

The collectins are very important for newborns without an acquired immune system – the MBLs will act as an opsonin. Babies without MBL will be highly susceptible to infection. The lectins are so important because there is no acquired immunity, so the nascent innate immunity of the newborn is extra important

Front 25

What are examples of pentraxins?

Back 25

Pentraxins are in a ring – CRP (c-reactive protein) and SAP (serum amyloid p) are acute phase proteins.

Front 26

What are the functions of the primary granules of neutrophils?

Back 26

Defensins - respiratory burst
myeloperoxidase - respiratory burst
neutral and acid hydrolases - degrade bacteria
lysozymes - destroy bacterial cell walls

Front 27

What are the functions of the secondary granules of neutrophils?

Back 27

Lysozymes - destroys bacterial cell walls

Lactoferrin - binds the iron that bacteria require, incapacitating them.

Collagenase - degrades connective tissue