T Cells and the Destruction of Cell-Associated Invaders

Question 1

Cytotoxicity

Answer 1

the ways in which T lymphocytes, mononuclear phagocytes, and granulocytes can kill target cells

Question 2

What kind of cells are killed through cytotoxicity?

Answer 2

cells that have become infected with viruses or intracellular microorganisms, abnormal/cancer cells

Question 3

What is another name for cytotoxicity?

Answer 3

type 1 immunity

Question 4

What do macrophages mainly kill?

Answer 4

intracellular bacteria

Question 5

What do cytotoxic T cells mainly kill

Answer 5

virus-infected cells

Question 6

Cytotoxic T cells

Answer 6

recognize endogenous antigens associated with MHC I

Question 7

First Pathway of destruction of target cell by CTL

Answer 7

1. the attacking cell releases the contents, including perforin and granzymes at the junction between the cells (made by LFA-1)
2. Induce apoptosis in viral infected target cells
3. Can also produce antibacterial proteins
4. Will kill some tumor cells

Question 8

Perforin

Answer 8

pore-forming molecule which polymerizes on the target cell membrane to form channels.

Question 9

Granzymes

Answer 9

found on the granules of cytotoxic T cells, which may enter the target cell via perforin pores and induce apoptosis

Question 10

Second Pathway of destruction of target cell by CTL

Answer 10

1. FAS is a receptor belonging to the TNFR family expressed on many cell types
2. Ligation of FAS-L induces target cell death

Question 11

FAS

Answer 11

kill me receptor

Question 12

Classical Macrophage Cytotoxicity

Answer 12

mediated by PAMPs plus IFN gamma and IL-2 from Th1 cells and NK cells. Cells enlarge, increase their bactericidal activity, and acquire to the kill otherwise resistant organisms

Question 13

NK Cell Mediated Cytotoxicity

Answer 13

directed at target cells that fail to express MHC Class I or have changes in cell surface proteins associated with tissue damage. Provide a line of defense against viruses or tumors that attempt to evade immune recognition by downregulating MHC expression

Question 14

ADCC

Answer 14

antibody dependent cell-mediated cytotoxicity. Involves the recognition of target cells coated with antibody. NK cells use their Fc receptors. NK cell kills

Question 15

ADCC Process

Answer 15

1. antibodies bind antigens on the surface of target cells
2. NK cell CD16 Fc receptors recognize cell-bound antibodies.
3. Cross-linking
4. Tumor cells die by apoptosis

Question 16

NK Cells

Answer 16

1. first line of defense, buy time for TH and TC cells
2. Contain granules with perforin and granzymes
3. Do not require activation to become cytotoxic
4. No memory
5. No antigen-specific receptor; have Fc receptor
6. Can see decreased MHC I expression

Question 17

NK cells can detect the downregulation of expression of what important cell surface molecule?

Answer 17

MHC I