Lecture 1

Question 1

Define immunology

Answer 1

study of host defense against ; infectious agents, neoplasia, injury

Question 2

name some infectious agents

Answer 2

viruses, bacteria, fungi, parasites

Question 3

what is the key distinction of infectious agents?

Answer 3

self from non-self

Question 4

key distinction of neoplasia?

Answer 4

self from altered self

Question 5

key distinction of injury?

Answer 5

damaged self

Question 6

what 2 things greatly advanced our understanding of immune system and its fn?

Answer 6

molecular biology and genomics

Question 7

True or False: Immunology is static

Answer 7

False; non-static, always there, responds immediately

Question 8

What factors affect the immune system?

Answer 8

age, nutritional status, host genetics, drugs, confounders/co-infectors, smoking, stress

Question 9

What are the 2 divisions of IS?

Answer 9

innate and adaptive

Question 10

What are the 2 components that make up each division?

Answer 10

humoral (cell-free) and cellular

Question 11

Describe components of innate immunity

Answer 11

always there, identifies with non-self
humoral: complement, cytokines/chemokines, antimicrobial peptides
Cellular: monocytes (macrophages and dendritic cells), NK cells, granulocytes (mast cells, eosinophils, basophils, neutrophils)

Question 12

Describe components of adaptive immunity

Answer 12

slower response, identifies with specific antigens
Humoral: antibodies
Cellular: B cells, T cells (helper T cells, cytotoxic T cells, regulatory T cells)

Question 13

Milestones

Question 14

What is immunity mediated by?

Answer 14

organs, cells and molecules

Question 15

Where are immunocytes derived from?

Answer 15

bone marrow during hematopoiesis

Question 16

What are the two types of responses?

Answer 16

natural or acquired; innate/existing/non-clonal vs adaptive/induced/clonal

Question 17

Name the components of the immune system?

Answer 17

soluble, cellular and tissues

Question 18

What produces soluble components?

Answer 18

immune cells, fibroblasts, epithelial cells, hepatocytes

Question 19

What do soluble comp affect?

Answer 19

differentiation and activities of immune cells; can have direct action on invading pathogen or tumors

Question 20

What do cellular comp involve?

Answer 20

innate and adaptive responses

Question 21

What do tissues involve?

Answer 21

primary and secondary organs

Question 22

Where do cells of immune system originate?

Answer 22

in the bone marrow (from hematopoietic stem cells), migrate through the blood and lymphatic systems, then function in peripheral tissues

Question 23

Simply describe differentiation pathway

Answer 23

hematopoietic stem cell –> common lymphoid progenitor (B/T cell, NK cell) OR common myeloid progenitor (granulocyte macrophage progenitor -> neutrophil, eosinophil, basophil, monocyte; megakaryocyte erythrocyte progenitor -> megakaryocyte (platelets), erythroblast (erythrocyte))

Question 24

What drives differentiation of immune cells down each pathway?

Answer 24

cytokines

Question 25

What do innate and adaptive immunity rely on?

Answer 25

WBC called leukocytes

Question 26

In the fetus, where are stem cells first produced?

Answer 26

liver and yolk sac

Question 27

What are the two pathways stem cells can differentiate into?

Answer 27

myeloid or lymphoid

Question 28

Describe features of neutrophils

Answer 28

• also called PMNs - polymorphonuclear neutrophil granulocyte
• most numerous cell of innate immunity
• responsible for phagocytosis and digestion of bacteria and particles
• contain multi-lobed nuclei and cytoplasmic granules
• short life spans - 2 days
• species differentiation in % of blood leukocytes (low in rum, high in carnivores)

Question 29

Describe features of granulocytes (esoinophil, basophil, mast cell)

Answer 29

• kills antibody-coated parasites

- release of granules containing histamine - agents

Question 30

Describe features of macrophages

Answer 30

• most important phagocytic cell (regulating homeostatic processes and wound healing)
• mononuclear cells found in blood and all tissues
• rel long-lived (months) in certain tissues
• secrete pro-inflammatory cytokines
• present processed antigen to T cells
• phagocytosis
• help initiate adaptive immunity
• antigen presentation

Question 31

Describe dendritic cells

Answer 31

• NOT dendrites
• found in low numbers in tissues (skin epithelia, intestinal, respiratory, repro mucosae)
• migrate to draining lymph node after pathogen uptake
• most important APC
• provides link btw innate and adaptive
• most either lymphocytic or myeloid origin

Question 32

Describe lymphocytes

Answer 32

• lymphoid progenitor from bone marrow or bursa
• leave bone marrow only partially mature
• B cells mature in lymph nodes, T cells differentiate in thymus
• small, round cells -> surface markers distinguish classes
• mediate adaptive immunity (receptors specific for epitopes)
• found in blood and lymphoid organs
• once “selected’ –> clonal replication
• get rid of ones that respond to “self”

Question 33

Describe features of NK cells

Answer 33

• lymphocyte lineage but NOT really lymphocyte
• possess different antigen receptors than B/T cell
• doesn’t require thymus for maturation
• 15% of blood lymphocytes
• most in secondary lymphoid organs
• kill tumor cells and virally-infected cells
• possess an Fc receptor -> bind many types of antibodies
• secrete interferons, IFN

Question 34

Describe the innate immune response

Answer 34

immediate, pre-formed molecules, specificity inherited in genome, response identical each exposure, mediated by monocyte, neutrophil and NK cells, no antigenic memory

Question 35

Describe adaptive immune response

Answer 35

delayed response, receptors rearrange, clonal expansion of cell subsets, response improves over time, mediated by T and B cells, antigenic memory