T-cell Activation

Question 1

What are Effector T-cells?

Answer 1

T-cells that have been activated and actively carrying out their function

Question 2

How does Dendritic Cell Activation occur?

Answer 2

When the dendritic cell binds to a pathogen PAMP, or there are inflammatory cytokines present

Question 3

What do dendritic cells do following activation?

Answer 3

Synthesize B7, increase antigen processing, and upregulate the chemokine receptor CCR7

Question 4

T-cell activation requires 3 signals, what are they?

Answer 4

Signal 1: T-cell receptor complex binds to a peptide: MHC complex that is presented by a dendritic cell.
Signal 2: CD28 on t-cells binds to the costimulatory molecule B7 on mature dendritic cells.
Signal 3: Cytokines signal to the t-cell (IL-2)

Question 5

What does Interleukin-2 (IL-2) do to affect T-cells?

Answer 5

When IL-2 binds to the T-cell receptor for it, there are numerous copies of that T-cell made, proliferation

Question 6

How do effector CD8 T-cells kill infected cells?

Answer 6

T-cells will form a conjugate pair with the infected cells, and release cytokines and cytotoxins through a synapse, focusing delivery at the point of contact- perforin will create a pore in the cell membrane

Question 7

What activates apoptosis within target cells of T-cells?

Answer 7

Granzymes, a form of proteases, activate apoptosis.

Question 8

What are the CD4 T-cell variants?

Answer 8

Helper T-cell 1, Helper T-cell 2, Helper T-cell 17, Follicular helper T-cell, Regulatory T-cell

Question 9

What is the role of Th1 T-cells?

Answer 9

To activate macrophages, important in the response to viruses and intracellular bacteria

Question 10

What is the role of Th17 cells?

Answer 10

To enhance the neutrophil response, important in the response to extracellular bacteria

Question 11

What is the role of Th2 cells?

Answer 11

To activate the cellular and antibody response to parasites

Question 12

What is the role of T-fh cells?

Answer 12

To activate B-cells and mature the antibody response

Question 13

What is the role of regulatory T-cells?

Answer 13

To suppress other effector T-cells, can be induced (85%) or natural (15%)

Question 14

What purpose do granulomas serve?

Answer 14

To isolate antigens that can not be eliminated from the body

Question 15

What purpose do gamma: delta T-cells have?

Answer 15

They maintain tissue integrity by killing infected or damaged cells and promoting tissue regeneration, thought of as a more innate based cell.

Question 16

What are the symptoms and pathology of severe combined immunodeficiency (SCID)?

Answer 16

There are NO functional T-cells, causes include IL-2 gene mutation (proliferation), a RAG protein mutation, or abnormal thymic development

Question 17

What are the symptoms and pathology of acquired immunodeficiency syndrome (AIDS)?

Answer 17

HIV will gradually deplete the body’s T-cells, and will become AIDS when the T-cell number declines to a dangerously low level.