immuno lec 3 lymphocytes Flashcards

1
Q

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

A

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

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2
Q

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

A

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

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3
Q

What happens to WBC number during infections?

A

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

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4
Q

Having extremely low neutrophils in the blood is called:

A

Neutropenia (can be congenital or acquired)

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5
Q

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

A

lymphocytes, it induces proliferation and differentiation.

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6
Q

How can naive T cells be activated?

A

Only by dendritic APCs

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7
Q

What are dendritic cells and where are they found?

A

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

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8
Q

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

A

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

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9
Q

What are follicular dendritic cells and their functions?

A

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.

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10
Q

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

A

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

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11
Q

Where do B cells present their antigens?

A

lymph nodes and spleen to T cells .

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12
Q

How does the MHC 1 work?

A

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

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13
Q

How and where does MHC 2 function?

A

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

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14
Q

What are the types of lymphocytes in the body?

A

Natural killer cells
T cells
B cells

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15
Q

How do natural killer cells function?

A

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.

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16
Q

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

A

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

17
Q

What are CDs

A

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

18
Q

What do T cells do?

A

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.

19
Q

What is humoral immunity and cell-mediated immunity?

A

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

20
Q

What are perforin granzymes?

A

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

21
Q

What is the distribution of lymphocytes in the body?

A

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

22
Q

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

A

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

23
Q

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

A

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