(26) Leukocyte Trafficking

Question 1

1. Lymphocytes contiously migrate (traffic, home) from the blood into tissue sites to do what two things?
2. Examples of primary lymphoid organ? What happens here?
3. Examples of secondary? What happens here?

Answer 1

1. find antigen presenting cells and perform their specific effector functions (eg, help macrophage, kill target cells, secrete antibodies)
2. bone marrow, thymus, Peyer’s patch (in some animals); differentiation
3. peripheral lymph nodes, peyer’s patch; activation of lymphocytes (mostly naive)

Question 2

1. What are at portals of antigen entry?
2. What does spleen do?
3. What is GALT? examples? What does it do?
4. What is BALT? What does it do?
5. What is SALT? what is it? what does it do?

Answer 2

1. lymphoid compartments
2. filters blood
3. gut associated lymphoid tissue; Peyer’s patch, mesenteric lymph nodes; collects antigens crossing mucosal epithelium
4. Bronchial-associated lymphoid tissue; Collects antigens crossing mucosal epithelium of lungs
5. Skin associate lymphoid tissue; peripheral lymph nodes; collects antigens crossing skin epithelium

Question 3

(Lymphocyte trafficking)

1. What two routes do lymphocytes use to enter the lymph nodes?
2. How do they leave?

Answer 3

1. blood vessels and lymphatics
2. efferent lymphatics

look at slide

Question 4

(Lymphocyte Trafficking)

1. Lymphatic fluid drains from the tissue into what?
2. Eventually returns to blood via what?

Answer 4

1. secondary lymphoid organs
2. the thoracic duct

(look at slide)

Question 5

1. Are lymphocytes in constant motion?
2. What are T and B cells that have never encountered or responded to their specific antigen? These cells continuousloy migrate through what?
3. What are T and B cells that have differentiated from naive lymphocytes upon stimulation by specific antigen?

Answer 5

1. yes
2. Naive lymphocytes; through all of the secondary lymphoid organs
3. effector lymphocytes

Question 6

Answer 6

C

Question 7

(Effecotor Lymphocyte Trafficking)

1. What sites are effector lymphocytes capable of entering?
2. Do they recirculate in a more selecitve manner? With a preference for what? Why do they do this?

Answer 7

1. sites of inflammation
2. yes; preference towards the lymphoid compartment they first encountered antigen in; more likely to encounter again in this compartment (antigens usually come to the same hangouts)

Question 8

Answer 8

A

Question 9

(Lymphocyte Trafficking)

1. What is it regulated by?
2. Specific combinations of these allow for what?
3. Upon antigen recognition and clonal expansion, what can lymphocytes do?

Answer 9

1. adhesion molecules and chemokines
2. very tissue selective lymphocyte migration (homing)
3. change the adhesion molecules and chemokine receptors they express