Lec 3: Cells of the Immune System

Question 1

HSCs

Answer 1

Hematopoietic stem cells (CD34+)

Have the ability to differentiate into many types of cells, that is, they are pluripotent.

They form two main branches of cells (CMPs= common myeloid progenitor cells and CLPs=common lymphoid progenitor cells)

Question 2

Where are HCSs derived from A

where are they from B

Answer 2

A the mesoderm

B red bone merrow

Question 3

erythrocytes

Answer 3

red blood cells
anuclear
CD235a+

Question 4

leukocytes

Answer 4

white blood cells

Question 5

Fixed leukocytes

Answer 5

tissue resident cells

Question 6

Why would the proportaion of types of white blood cells change from person to person

Answer 6

Proportion of cells will change with age, usually from pre-existing conditions, immunological history and if a given person is currently infected

Question 7

CMP

Answer 7

conmmon myeoid progenitor cells

Question 8

CLP

Answer 8

Common lymphoid progenitor cells

Question 9

Hematopoeisis

Answer 9

generation of immume cells from self renewing cells in the bone marrow

Question 10

What causes new cell types to be formed hematopoeisis

Answer 10

Transcription factors and or micro silencing RNA

Question 11

Is the process of Hematopoeisis required throughout the life of an indivudual?

Answer 11

Yes, because as we age we encounter new types of infections and or immunological problems. We required hematopoeisis in order to maintain a repitoir of cells that are able to deal with and maintain our health// homeostatis during periods of new infection and diesease.

Question 12

What markers are found on HSCs?

Answer 12

They have the surface proteins CD34, Sca-1 and c-Kit

Question 13

Which cells do the CLPs give rise to

Answer 13

B lymphocytes
T lymphocytes
NK cells

dentridic cells

Question 14

Cells of the innate immune system

Answer 14

Myeloid and NK cells

These are the “First responders”

Question 15

Cells of the adaptive immuen system

Answer 15

Lymphocytes

Question 16

Where are Lymphocytes found

Answer 16

Lymphocytes are found in circulating blood as well as in tissue-resident populatons and is secondary lympoid organins ie: the spleen or lymph nodes

Question 17

Where are Lymphocytes found

Answer 17

Lymphocytes are found in circulating blood as well as in tissue-resident populatons and is secondary lympoid organins ie: the spleen or lymph nodes

Question 18

Platelet

Answer 18

Used to be removed from assays because they were thought to be junk!

We know know that they are important for a variety of functions including:

Immune activation
bacterial entrappment and destruciton
Neutrophil activation
natural function of dentridic and other immune cells

Question 19

Megakaryocytes

Answer 19

From platletes- cell fragments placed into circulation for clotting
CD41+
CD61+
CD62+

Question 20

Monocytes

Answer 20

From Myeloid progentors

Migrate into tissues and differentiate into macrophages (CD14+)

Can also differentiate into myeloid dendritic cells (CD11c+, CD123+)

Question 21

Macrophages

Answer 21

CD14+
repair/ remodel, destroy pathogens as well as present antigens
these are highly
phagocytotic

Question 22

Myeloid dentridic cells

Answer 22

CD11c+
CD123+
profressional antigen presenting cells

This means that they are the only cells capable of activating a naive T cell for the first time

Question 23

Whatr is a common CD marker of Granulocytes

Answer 23

CD66b+

Question 24

Neutrophils

Answer 24

Short lived with a life span of only a few days

First responder phagocytes

Question 25

Eosinophils

Answer 25

role in protection against multicellular parasites

play a role in allergic diseases

Question 26

Basophils

Answer 26

non-phagocytotic cells which release histamine

Question 27

Mast cells

Answer 27

found in tissues, release histamine and also play an important role in allergic disease

Question 28

FcR receptors

Answer 28

Bind antibodies onto the surface of immune cells

this gives specificity to
T-cells

Question 29

B cells

Answer 29

express B cell receptor (BcR), this aids to recognize intact antigens

have a large role in the synthesis of antibodies

naive B cells will differentiate into:
Memory B cells
Effector cells (secrete antibodies)

CD19+
CD20+

Question 30

T cells

Answer 30

Express the T cell receptor (TcR), this recognizes processed antigens held in major histocompatibility complex (MHC)

naive T cells differentiates into:
Memory T cells
effector cells
NK cells

CD3+

Question 31

Effector cells (cell types)

Answer 31

T helper cells CD4+

Cytotoxic T cells CD8+

other T cell subtypes

Question 32

MHC 1 presents to

Answer 32

CD8+ T cells

Question 33

MHC 2 presents to

Answer 33

CD4+ T cells

Question 34

NK cells

Answer 34

No BcR or TcR but rather has activating ligands

Recognize the absence of MHC 1

Important for killing tumour cells and virus infected cells

CD56+

Question 35

NKT cells

Answer 35

recognize non-protein antigens (like lipids and glycolipids) which are presented in CD1 (MHC-like molecule)

Question 36

What would cause the absence of MHC on a cell

Answer 36

viral infections or cancer

Question 37

Plasmacytoid dendridic cells

Answer 37

consituts a very small proportaion of peripherial blood mononuclear cells (PBMC’s)

specialized for detection of viruses and produce a large amount of interferon to recruit T-cells

CD11c-
CD123+
CD303+
CD304+

CD markers will vary btween species here

Question 38

Why are new immune cells constantly generated in the body

Answer 38

Because we kill so many of them during the maturation process

Question 39

What is the difference between myloid and lymphoid dentritic cells

Answer 39

myeloid dendritic cells capture antigens in the periphery and then migrate to the lymphoid organs to initiate immunity, whereas lymphoid dendritic cells are found in the thymic medulla and lymph node T cell areas and are responsible for tolerance