Lecture 41+42+DLA

Question 1

naïve T cells

Answer 1

stimulated by the microbial antigen in lymph nodes and spleen

express L-selectin
express CCR7 a chemokine receptor

Question 2

effector T cell

Answer 2

migrate to the site of infection

express E and P selectin
integrin LFA-1 and VLA-4
chemokine receptor changes

Question 3

IFN gamma

Answer 3

stimulate phagocyte mediated ingestion

expression of lysosomal proteases
synthesis of ROS
Ab production for phagocytosis

Stimulate expression of Class II MHC and B7 on APCs (amplify T cell response)

activated macrophages produce IL-12

Question 4

intracellular bacteria

Answer 4

inhibit fusion of phagosomes with lysosomes

escape into the cytosol and do not get phagocytosed

ex: mycobacterium, listeria

Question 5

inhibition of class I MHC-associated antigen presentation

Answer 5

many viruses can do this

Block transport of antigenic peptide from cytosol to ER
Removing class I MHC from ER
Result in reduced class I MHC on surface

can also produce inhibitory cytokines
can directly affect the T-cells also

Question 6

cell-mediated diseases and DiGeorge syndrome

Answer 6

Born without thymus, lack T cell component

Can fight extracellular pathogens but have
issues with intracellular pathogens (viruses, intracellular bacteria)

Question 7

Th2 cells

Answer 7

humeral mediated immunity

Stimulate phagocyte-independent eosinophil-mediated immunity
will attack parasites

produce IL-4 (stimulation of IgE production)
produce IL-5 (activates eosinophils)

L4 and IL-13 leading to IL10 production by M2
suppresses Th1

Question 8

Th17

Answer 8

induce inflammation
stimulate antimicrobial production: defensins

destroy extracellular bacteria and fungi

Question 9

Th17 defect

Answer 9

bacterial abscesses and chronic mucocutaneous candidiasis

Question 10

IL 17

Answer 10

recruit leukocytes (neutrophils)

Question 11

IL-22

Answer 11

important in epithelial barrier integrity

Question 12

Memory T lymphocytes

Answer 12

lymphoid organs = central memory cells

peripheral tissues = effector memory cells

require IL-7 to stay a lot
responsible for secondary response

Question 13

during the immune response

Answer 13

survival and proliferation is maintained by antigen, CD28 co-stimulation signal, and cytokines (IL-2)

Question 14

T-cell anergy

Answer 14

Inability of cells to proliferate in response to
engagement with MHC-peptide complex

Due to absence of appropriate costimulatory
signal or by CTLA-4 or another inhibitory signal