T Cell Activation

Question 1

Maturation of T cells

Answer 1

T cells mature in thymus and produce T cell receptor proteins
Some cells become killer T cells or helper T cells

Question 2

T cells

Answer 2

Play a central role in adaptive immune response
T cell receptor on surface

Question 3

What are the 2 kinds of T cells?

Answer 3

T helper (CD4 receptor)
T cytotoxic/killer cells (CD8 receptor)

Question 4

What is the function of T cells?

Answer 4

Destroy intracellular pathogens

Question 5

T cell antigen receptor

Answer 5

Two chain structure
Single binding site for antigenic peptides processed and presented by antigen presenting cells or virus infected cells

Question 6

TCR function

Answer 6

TCR recognizes small peptide fragment of antigen presented by MHC molecule

Question 7

TCR chains

Answer 7

85-95% have a and b polypeptide chains (a/b T cells)
Minor population has gamma/delta chains (g/d T cells)

Question 8

Cell-mediated immunity

Answer 8

No antibodies
Activation of phagocytes, antigen specific cytotoxic T cells, helper T cells
Release of various cytokines

Question 9

What do macrophages produce?

Answer 9

Nitric oxide that phagocytoses bacteria that activate other cells

Question 10

What does the macrophage do for the T cell?

Answer 10

Present antigens to T cells and initiate inflammation by releasing cytokines

Question 11

Alveolar macrophage

Answer 11

Location: lung alveoli
Phagocytosis of small particles, cells or bacteria
Initiation and control of immunity to respiratory pathogens

Question 12

Kupffer cells (macrophage)

Answer 12

Liver
Initiate immune responses and hepatic tissue remodeling

Question 13

Microglia (macrophage)

Answer 13

CNS
Elimination of old or dead neurons an control of immunity in the brain

Question 14

Splenic macrophages

Answer 14

Spleen marginal zone, red and white pulp
Elimination of dysfunctional or old RBCs

Question 15

How do macrophages detect products of bacteria?

Answer 15

Using a system of recognition receptors (toll-like receptors)
They bind specifically to different pathogen components like sugars, RNA, DNA, or extracellular proteins

Question 16

T cells don’t recognize _______ but recognize in association with ____________ molecules

Answer 16

1. Antigens
2. Histocompatibility complex (MHC)

Question 17

T helper cells

Answer 17

Recognize processed antigen on cells such as macrophages, B cells, dendritic cells
In association with MHC class 2 molecules

Question 18

Cytotoxic T cells

Answer 18

Recognize antigens synthesized within the target cells
Presented in association MHC class 1

Question 19

How does the cytotoxic T cell carry out its function?

Answer 19

1. Cytotoxic T cell binds to infected cell
2. Protein makes holes in infected cells membrane and enzyme enters
3. Infected cell destroyed