Cells and Tissues of Adaptive Immune

Question 1

Where do ALL blood cells develop from?

Answer 1

CD34+ pluripotent stem cells

Question 2

What progenitor cell gives rise to adaptive immune cells?

Answer 2

Lymphoid progenitor cells give rise to B cell progenitors and T cell progenitors

Question 3

How long do naive B and T cells live if they dont mature?

Answer 3

1-3 months

Question 4

When is the thymus the largest and most active?

Answer 4

Neonatal and pre adolescent periods

Question 5

What are the two types of T cells?

Answer 5

• T helper cells, which express CD4 and help B cells grow and differentiate
  
  • T regulatory cells are a subtype of helper
• Cytotoxic T lymphocytes which express CD8 and recognize and kill infected cells

Question 6

What is a thymoma?

Answer 6

slow growing tumor that starts in the epithelial cells of the thymus and does not spread beyond the thymus

Question 7

What is a thymic carcinoma?

Answer 7

aggressive cancer of thymus epithelial cells, and difficult to treat because of rapid spreading.

Question 8

How would removing the Thymus as an adult with a thymoma or thymic carcinaoma impact the immune system?

Answer 8

It wouldn’t because the thymus is no longer active, it is typically just adipose by adulthood.

Question 9

What type of bone marrow is present at birth?

Answer 9

All red bone marrow and turns to yellow and red by puberty

Question 10

Before birth where does differentiation into B cells occur?

Answer 10

Fetal liver

Question 11

How do stromal cells and cytokines impact development of B cells?

Answer 11

They are needed for cell to cell contact because they secrete Growth factors and cytokines send signals for growth as well.

Question 12

Leukemia?

Answer 12

Malignant disease of the bone marrow leading to a shortage of normal white and red blood cells and platelets. Patients often get infections, anemia and bruising occur easily.

Question 13

Myeloproliferative disorders?

Answer 13

Related to Leukemia as they are the overproduciton of one type of blood cecll and can develop into leukemia. The most common causes of death are infection, cardiovascular disease, cerebrovascular disease, hemmorrhage or thrombosis.

Cells lose specificity and function and are just overly abundant and take all of the growth factors.

Question 14

Multiple Myeloma?

Answer 14

Malignancy of plasma cells which produce proteins that impair development of normal blood cells causing anemia and leukopenia. Infection is major complication and cause of death for these patients.

Question 15

Lymphoma?

Answer 15

Cancer in circulating blood lymphocytes after production in bone marrow. Lymphomas can spread to bone marrow at the late stage. These patients have an increased risk for infectious diseases.

Question 16

Where do lymphocytes not circulate?

Answer 16

• Eyes
• Brain
• Testes

Question 17

Steps to B cell activation?

Answer 17

1. Naive B cells migrate to lymph node (or other 2 lymp tissues) where they look for soluble foregin Ags.
2. Ag activated B cells proliferate and mature into plasma cells or memory cells
3. Plasma cells produce and secrete large amounts of Abs
4. In spleen Ag activated B cells produce Abs against microbes in the blood

Question 18

Where is the T cell zone and B cell zone located in the spleen?

Answer 18

• T cell zone is centrally located aka: periarteriolar lymphoid sheath (PALS)
• B ccell zone is located around the T zone in packed follicles

Question 19

Steps to activate T cells?

Answer 19

1. Naive T cells migrate to LN searching for foregin Ags
2. T cells that are activated by DC’s differentiate into effector or memory T cells
3. Some effector and memory t cells migrate back to site of infection
4. some activated and differentiated t cellsstay in LN and help Ag activated B cells become plasma cell

Question 20

What is the only cell that can activate Naive T cells?

Answer 20

Dendritic Cell

Question 21

What is the relationship between B cells and primary and secondary follicles in lymph nodes?

Answer 21

The B cells are initally in primary follicles tightly packed around the periphery of the LN, these are naive cells. Once the B cell is exposed to Ag it is no longer naive and the follicle becomes secondary follicle aka Germinal center.

• Germinal centers of LN swell during infection

Question 22

What are the three professional APC’s?

Answer 22

1. Dendritic cells (DC)
2. Tissue Macrophages
3. B cells

Question 24

Describe the relationship between the professional APC’s and T Cells?

Answer 24

Naive T cells can only be activated by DC’s in the lymph node.

Macrophages and B cells can present Ag’s to only Mature T cells.

(DC and macrophages are innate cells- they link innate immunity and adaptive immunity)

Question 25

Where do classical DC’s reside?

Answer 25

Skin mucosa and organ parenchyma

when they are activated they migrate to LN

Question 26

What are pDC’s?

Answer 26

• Plasmacytoid DC- which is found in secondary lymphoid organs and are early cellular responders to viral infections
• They recognize nucleic acids of viruses and produce solube interferons (IFN-a/B)