Overview of Immune System

Question 1

What is Innate Immune response?

Answer 1

Fast - first responders, within minutes (neutrophils)

nonspecific - looks for broad signs of pathogens and tissue damage

Question 2

What is adaptive immune response

Answer 2

T and B cells
delayed response
very specific, can differentiate between good and bad E. coli

Question 3

Myeloid Lineage: What are the granulocytes?

Answer 3

For innate response- have granules in cytoplasm that are realized when near pathogens

1) Neutrophil
- most abundant, first responder (it uses phagocytosis)
2) basophil
- inflammatory and allergic responses
3) eosinophils
- parasitic infections and allergic responses

Question 4

Myeloid Lineage: What are the phagocytes?

Answer 4

for innate response - eat pathogens and clear debris

1) monocytes
- circulate in blood and enter into tissue and then will differentiate into the next two cell types depending on need
2) macrophage
- reside in all tissues, antigen presenting cells to help adaptive immune system
3) dendritic cells
- similar to macrophage, can activate naive t- cells , very good at antigen-presenting

Question 5

What are mast cells?

Answer 5

• not a phagocyte or granulocyte!

contains granules, involved in parasitic worms and allergic response (like eosinophils)

Question 6

Lymphoid Lineage: What are T lymphocyte?

Answer 6

adaptive immunity, antigen specific, lots of different types of t-cells like cytotoxic (CD8) and helper (CD4) and is a suppressor/regulatory - helps turn the immune response off

Question 7

Lymphoid Lineage: What are B-lymphocytes?

Answer 7

adaptive immunity, differentiate into plasma cells which secrete antibodies. one b-cell makes one antibody that is specific to one antigen.

Question 8

Lymphoid Lineage: What are NK cells?

Answer 8

are involve in innate immune response and kill virally infected and tumor cells - not antigen specific. Are still lymphoid.

Question 9

How to immune cells communicate?

Answer 9

1) secretion of signaling molecules
- cytokines: signaling molecules to other cells, involved in both types of immunity
- chemokine: sub group of cytokines; involved in chemotaxis or helping cells move towards the pathogen
2) Activation of receptors
- internal: starts cascade process within cell
- external: where other cells can bind to the outside membrane

Question 10

Distinguish the importance of primary and secondary lymphoid tissues

Answer 10

Primary: bone marrow (hematopoiesis) and thymus (maturation site of T cells), production of leukocytes
Secondary: everything else besides the two above. Areas exposed to external environment through breathing, eating, etc. Filters that help us catch pathogens and recognize them with our WBC.

Question 11

What are the migration paths of leukocytes and lymphocytes?

Answer 11

Most leukocytes don’t leave tissue once it has entered - they die there.
if they do move, they go through a process of transmigration (aka diapedesis)
- basically adhesion cells slow down the quickly moving leukocytes and allow it to transmigrate through the wall of the blood vessels into the tissue (slows down traffic) (chemokines do this)
Lymphocytes can recirculate - they go into a lymph node, hangout for 12-24 hours and if they don’t find anything, go back into the tissue to go to the next lymph node