immuno lec 3 lymphocytes

Question 1

What is the # of WBCs in 1 microliter of blood in a healthy individual?

Answer 1

4,500-11,000
(7,500 mean)

Question 2

What are the types of white blood cells and their cell count per microliter?

Answer 2

Neutrophils (4400)
Eosinophils (200)
Basophils (40)
Lymphocytes (2500)
Monocytes (300)
total (7400)

Question 3

What happens to WBC number during infections?

Answer 3

No change in blood WBC count and the response is usually localized to the tissues.

Question 4

Having extremely low neutrophils in the blood is called:

Answer 4

Neutropenia (can be congenital or acquired)

Question 5

To what cells do APCs signal to and what are the general effects?

Answer 5

lymphocytes, it induces proliferation and differentiation.

Question 6

How can naive T cells be activated?

Answer 6

Only by dendritic APCs

Question 7

What are dendritic cells and where are they found?

Answer 7

Phagocytic cells with antigen-presentation capability. They are found in organ parenchyma, mucosal epithelium, and lymphoid tissue.

Question 8

What are the 2 true types of dendritic cells and their functions?

Answer 8

conventional dendritic cells, mainly for antigen presentation to T cells.
Plasmacytoid dendritic cells, used for interferon type 1 synthesis upon viral stimulation

Question 9

What are follicular dendritic cells and their functions?

Answer 9

Cells with membranous projections, found in germinal centers surrounded by activated B cells in lymph nodes and spleen. They capture Ag-Ab and present them to B cells without modifications.

Question 10

What cells bind to macrophage APC and what are the effects?

Answer 10

Helper T cells, results in activation of these T cells and production of molecules that increase phagocytic function

Question 11

Where do B cells present their antigens?

Answer 11

lymph nodes and spleen to T cells .

Question 12

How does the MHC 1 work?

Answer 12

proteins in most cells are degraded by a proteosome and are then displayed on MHC 1, which works as an inhibitory signal for natural killer cells.
Cytotoxic T cells will lyse the cell if it presents antigens on MHC 1

Question 13

How and where does MHC 2 function?

Answer 13

Found on dendritic and B cells in addition to macrophages and some endothelial cells. MHC 2 displays antigens for different lymphocytes like helper T cells

Question 14

What are the types of lymphocytes in the body?

Answer 14

Natural killer cells
T cells
B cells

Question 15

How do natural killer cells function?

Answer 15

works in innate immunity against intracellular infections. They are able to lyse cells without stimulation. To be stopped, inhibitory signals like MHC 1 must be present on the surface of the cell.

Question 16

Where do B and T cells originate and where do they mature?

Answer 16

Both from bone marrow.
B cells early maturation in bone marrow
T cells mature in the thymus

Question 17

What are CDs

Answer 17

Cluster of differentiation. surface molecules that are used to identify cells and serve as ligands or receptors.

Question 18

What do T cells do?

Answer 18

When detecting an antigen on MHC 1, cytotoxic T cells lyse the infected cell. When detecting MHC 2, helper T cells release cytokines and induce phagocytosis and inflammation.

Question 19

What is humoral immunity and cell-mediated immunity?

Answer 19

Humoral: mediated by antibodies
Cell-mediated: mediated by T lymphocytes

Question 20

What are perforin granzymes?

Answer 20

Molecules released by killer T cells and have a serine protease function that triggers apoptosis of the cell via caspase cascade.

Question 21

What is the distribution of lymphocytes in the body?

Answer 21

2% blood
10% bone marrow
15% mucosal lymphoid tissue
65% lymphoid organs like the spleen

Question 22

How are T cells able to bind to each possible antigen?

Answer 22

Each clone of the T cells has a unique antigen receptor, there are countless T cells so new antigens can be detected.

Question 23

How are T cells able to form different antigen receptors with the same genes?

Answer 23

Genes encoding for antigen receptors are recombined during the maturation of T cells.