Imm 2 - Antigen Presentation

Question 1

Where are T cells made and matured?

Answer 1

They are made in bone marrow. They travel to the thymus where a few are selected.

Question 2

What surface marker do all T cells have?

Answer 2

CD3.

Question 3

What surface marker do helper T cells have?

Answer 3

CD4.

Question 4

What surface marker do Cytotoxic T cells have?

Answer 4

CD8.

Question 5

What type of cells are 80% of the lymphocytes in circulation?

Answer 5

T cells.

Question 6

Which type of cells bind to MHCII?

Answer 6

CD4+ helper T cells.

Question 7

What are Cytotoxic T cell supposed to do?

Answer 7

Virus-infected cells. Cancer cells.

Question 8

How can cytotoxic T cells differentiate b/w healthy cells and diseased cells?

Answer 8

Major Histocompatibility Complex I (MHC I), which is presented by every nucleated cell in the body (this excludes RBCs).

Question 9

Which type of cell binds to MHCI on virus infected cells or cancer cells?

Answer 9

CD8 cytotoxic T cells.

Question 10

What genes code for MHCs?

Answer 10

HLA genes: human leukocyte antigens.

Question 11

Which genes code for MHC I?

Answer 11

HLA-A. HLA-B. HLA-C.

Question 12

Which genes code for MHC II?

Answer 12

HLA-DR. HLA-DP. HLA-DQ.

Question 13

Which diseases are associated w/ HLA-B27?

Answer 13

[27 PAIRs] Psoriatic arthritis. Ankylosing spondylitis. Inflammatory bowel disease. Reactive arthritis (Reiter syndrome).

Question 14

Which diseases are associated w/ HLA-DR3/DR4?

Answer 14

Type 1 diabetes mellitus.

Question 15

What three cells express MCH II?

Answer 15

They are antigen presenting cells: macrophages, certain B cells but the vast majority are dendritic cells.

Question 16

What is the job of Dendritic cells? How do they do this?

Answer 16

To capture antigen at one location and present antigen at another location. This is accomplished by migration to lymph nodes for presentation to T cells. Antigens are captures by phagocytosis, receptor-mediated endocytosis or pinocytosis.

Question 17

What are Dendritic cells? What are its characteristics?

Answer 17

They are antigen presenting cells. They are covered w/ long membranous extensions that resemble the dendrites of nerve cells. All display both class I and II MHC, and a B7 protein (either CD80 and CD86). All have CD40 which can interact w/ T cells to further activate the antigen presenting cell.

Question 18

What are two different type of dendritic cells?

Answer 18

Langerhans cells found in epidermal layers of skin (cutaneous-associated lymphoid tissue, CALT). Interstitial dendritic cells, found in the interstitial spaces of virtually all organs (except brain).

Question 19

What is Langerhans Cells Histiocytosis?

Answer 19

Disease where there is an excessive proliferation of Langerhans cells and they are no good at presenting antigens. These cells express S-100 tumor marker and CD1a. They have Birbeck granules (tennis rackets within the cell).

Question 20

What molecules are expressed on the surface of antigen presenting dendritic cells?

Answer 20

MHC I. MHC II. B7 protein. CD40.

Question 21

What characteristic findings would you see on electron microscopy of a dendritic cell w/ Langerhands cell histiocytosis?

Answer 21

Birbeck granules.

Question 22

Which MHC class is recognized by helper T cells? Which MHC class is recognized by cytotoxic T cells?

Answer 22

Helper T cells recognize by MCH II. Cytotoxic T cells are recognized by MHC class I.