L2: Cells and Tissues

Question 1

What are non-self entities?

Answer 1

Things that express molecules (antigens) that can be recognized by cells of the immune system

Question 2

What are the major groups of human pathogens?

Answer 2

Viruses, bacteria, fungi, parasites

Question 3

How was smallpox vaccine discovered?

Answer 3

Smallpox is caused by the variola virus. Discovered that milkmaids, who were exposed to cow pox (variolae vaccinae) did not get smallpox. Then took scrapings from pustules of milkmaid and inoculated someone, then did the same w/ small pox and pt did not get smallpox. Smallpox was officially eradicated in 1979

Question 4

What is the most primitive form of the immune system?

Answer 4

Innate immunity

Question 5

How long after infection does innate immunity kick in?

Answer 5

Minutes to hours

Question 6

What does the innate immune system consist of? What does the adaptive immune system consist of?

Answer 6

Innate: epithelial barriers, complement, phagocytes, NK cells

Adaptive: B lymphocytes, T lymphocytes

Question 7

What microbe does humoral immunity respond to? What are the responding lymphocytes? What is the effector mechanism?

Answer 7

Microbe: extracellular bacteria

Responding lymphocytes: B lymphocyte

Effector mechanism: secreted antibody, causing elimination of bacteria

Question 8

What microbe does cell-mediated immunity respond to? What are the responding lymphocytes? What is the effector mechanism?

Answer 8

Microbe: phagocytosed microbes in macrophage and virus-infected cell

Responding lymphocytes: T lymphocytes

Effector mechanism: For phagocytosed microbes in macrophage, causes activation of macrophage leading to microbial killing

For virus-infected cell, causes lysis of infected cell

Question 9

How are humoral and cell-mediated immunity transferred?

Answer 9

Humoral immunity is passively transferred by serum (antibodies)

Cell-mediated immunity transfer requires transfer of cells

Question 10

What is the effector function of B lymphocytes?

Answer 10

Produces antibodies

Causes neutralization of microbe, phagocytosis, complement activation

Question 11

What is the effector function of helper T lymphocytes?

Answer 11

Produces cytokines

Causes activation of macrophages, inflammation, and activation (proliferation and differentiation) of T and B lymphocytes

Question 12

What is the effector function of cytolytic T lymphocytes?

Answer 12

Killing of infected cell

Question 13

What is the effector function of natural killer (NK) cells?

Answer 13

Killing of infected cell

Question 14

What are the phases of the adaptive immune response?

Answer 14

Recognition phase
Activation phase
Effector phase: elimination of antigens
Decline (homeostasis): apoptosis
Memory: surviving memory cells

Question 15

When antigen comes in, why is there a lag time before immune response occurs?

Answer 15

There is activation, clonal expansion, and differentiation of B cells to produce antibody

Question 16

How is secondary immune response different from primary immune response?

Answer 16

Lag time is shorter
Level of antibody produced is higher
Quality of antibody is more specific
Lasts longer in circulation

Question 17

In hematopoiesis, what determines what the stem cell becomes?

Answer 17

Microenvironment of bone marrow and also cytokines that are present

Question 18

Where does B lymphocyte and T lymphocytes maturation occur?

Answer 18

B lymphocytes in bone marrow

T lymphocytes in thymus

Question 19

Once they are released to the blood, where do B and T lymphocytes take up residence?

Answer 19

In the peripheral lymphoid organs

Lymph nodes
Spleen
Mucosal and cutaneous lymphoid tissues

Question 20

What criteria are used to distinguish various lymphocyte subsets?

Answer 20

Cell surface markers
Patterns of cytokine production
Functional characteristics

Question 21

What are significant surface markers of human B cells?

Answer 21

Antibody molecule that is stuck in the membrane w/ the 2 antigen combining sites exposed

MHC I
MHCII

Question 22

What are the significant surface markers of human T cells?

Answer 22

MHC I

T helper cell: CD4

T cytotoxic cell: CD8

Question 23

What are the T cell subsets? What do they do?

Answer 23

Helper T lymphocytes: make cytokines that amplify the immune response; cause activation of macrophages, inflammation, activation (proliferation and differentiation) of T and B lymphocytes

Cytolytic T lymphocytes (CTLs): killing of infected cell

Question 24

How are natural killer cells different from cytotoxic T cells?

Answer 24

They are part of innate immune response that don’t require antigen recognition to kill infected cell

Question 25

What is an alternate name for NK cells?

Answer 25

Large granular lymphocytes bc of the unique granules in their cytoplasm

Question 26

What are the significant cell surface markers of human monocytes/macrophages?

Answer 26

MHC II

Question 27

What are the antigen presenting cells?

Answer 27

Dendritic cells and macrophages

Question 28

Describe how antigen presenting cells present antigen peptides

Answer 28

1. Bacterium infects macrophage and enters vesicle, producing peptide fragments 2. Bacterial fragments are bound by MHC class II in vesicles 3. Bound peptides transported by MHC class II to the cell surface

Question 29

What does T helper cell recognize?

Answer 29

Recognizes complex of bacterial peptide w/ MHC class II and activates macrophage

Question 30

What lymph vessels go into and out of lymphoid tissues?

Answer 30

Afferent vessels coming in and efferent going out

Question 31

Where do all lymphatic vessels coalesce?

Answer 31

In the major lymphatic vessel of the body, the thoracic duct, which empties into the peripheral circulation around the great vessels near the heart

Question 32

Where do B cells reside in lymph nodes?

Answer 32

In germinal centers (follicles) which are in the periphery of the lymph node

Question 33

Where do T cells reside in the lymph node?

Answer 33

In the T cell zone, which is just beneath the B cell zone